University of Groningen The course of whiplash Buitenhuis, Jan · 2016. 3. 9. · Albeit suffering...

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The course of whiplashBuitenhuis, Jan

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The Course of Whiplash

Its Psychological Determinants and Consequences for Work Disability

Copyright © 2009 J. Buitenhuis

Niets uit deze uitgave mag worden verveelvoudigd, opgeslagen in een geautomatiseerd gegevensbestand of openbaar gemaakt in enige vorm of op enige wijze zonder vooraf-gaande schriftelijke toestemming van de auteur.

All rights reserved. Nothing from this publication may be duplicated, stored in an auto-mated database, or made public, in any form or any manner, whether electronic, me-chanical, through photocopying, recording, or any other manner, without prior written permission from the author.

Ontwerp - DesignOmslagconcept en –ontwerp – Cover design: Miazo - Communication & Design, www.miazo.comLayout: P. van der Sijde, GroningenDruk - press: Van Denderen, Groningen

ISBN: 97877113851

RIJKSUNIVERSITEIT GRONINGEN

The Course of Whiplash

Its Psychological Determinants and Consequences for Work Disability

Proefschrift

ter verkrijging van het doctoraat in de Medische Wetenschappen

aan de Rijksuniversiteit Groningen op gezag van de

Rector Magnificus, dr. F. Zwarts,in het openbaar te verdedigen op

woensdag 3 juni 2009om 14.45 uur

door

Jan Buitenhuis

geboren op 18 juli 1964 te Meppel

Promotores: Prof. dr. J.W. Groothoff Prof. dr. P.J. de Jong

Copromotor: Dr. J.P.C. Jaspers

Beoordelingscommissie: Prof. dr. R.J. van den Bosch Prof. dr. H.J. ten Duis Prof. dr. J.W.S. Vlaeyen

Aan Marjolein, Anne, Bart en Irene

Paranimfen: P. Pliva J. Spanjer

Contents

Chapter 1 Introduction 9

Chapter 2 Work disability after whiplash: a prospective cohort study 29 Spine 2009;34(3):262-7

Chapter 3 Recovery from acute whiplash: The role of coping styles 43 Spine 2003;28(9):896–901

Chapter 4 Can kinesiophobia predict the duration of neck symptoms in 57 acute whiplash?

The Clinical Journal of Pain 2006;22(3):272-77

Chapter 5 Relationship between posttraumatic stress disorder symptoms 73 and the course of whiplash complaints Journal of Psychosomatic Research 2006; 61:681– 89

Chapter 6 Catastrophizing and causal beliefs in whiplash 93 Spine 2008;33(22):2427–33

Chapter 7 General discussion and conclusions 109

Summary 129

Samenvatting 137

Dankwoord 145

About the author 149

9

Introduction

1

10

Chapter 1

11

1

Introduction

Introduction

Coinage of the term whiplash is claimed by H.E. Crowe in relation to his presentation of eight cases of neck injury to a medical meeting in San Francisco in 1928.1 The term refers to a specific movement of the head due to a rear-end motor vehicle collision. Later the term whiplash was used to refer to the complex of symptoms itself. In 1995, the Quebec Task Force introduced the term Whiplash Associated Disorder (WAD) to capture the wide variety of symptoms attributed to whiplash by that time.2 Other terms used in the literature are late or post-whiplash syndrome, to indicate symptoms after a whiplash accident or movement.

Although the majority of patients show spontaneous recovery within the first few months after a traffic accident, in as many as 40 percent of cases acute complaints lead to a chronic syndrome with neck pain and often accompanying cognitive complaints.3 To date no somatic injury has been identified that can explain the chronic symptoms, which are thereby generally identified as medically unexplained, and this has given rise to various views, studies and controversies regarding their possible somatic, psychological or psychosomatic nature.

In 1964, Crowe himself stated that he regretted the coinage.1 He wrote that the expression was intended to be a description of motion, but that it had become accepted by physicians, patients and attorneys as the name of a disorder, and that this misunderstanding had led to its misapplication by many physicians and others over the years. Indeed, when Crowe introduced the term ‘whiplash injury’ in 1928 he could hardly have imagined to what medical and social controversy it would lead.

Over the last decades chronic neck pain has become a common complaint following motor vehicle accidents in various countries. Often the neck pain is accompanied by cognitive and other complaints. Over the years the symptoms reported have become increasingly varied. The accident is still the prerequisite to the complaints and has become defined in ever broader terms until today any accident can be considered a possible ‘whiplash accident’. 2

The main feature of whiplash is neck pain. There may be a wide variety of other symptoms accompanying the neck pain, but the presence of neck pain is usually considered to be a requirement for the diagnosis of whiplash. Because the term ‘whiplash’ itself is actually a description of a movement, it is poorly defined with regard to accompanying symptoms, and due to its possible dysfunctional connotation many even choose not to use the word at all. An alternative name might be post-traumatic neck pain (PTNP). This name clearly indicates that neck pain is the central symptom and that it has a post-traumatic origin, although some may find this to be too narrow a definition.

Throughout the studies reported in this thesis, the term whiplash and post-whiplash

12

Chapter 1

syndrome are used because of their familiarity to physicians and other potential readers, although the appropriateness of these labels may be subject to discussion.

Whiplash in the Netherlands

Dutch research and scientific publicationsDutch-language scientific articles on whiplash are relatively scarce. One of the first articles published was by Jongkees in 1974.4 In his ‘clinical lesson’ he asked that attention be given to post-traumatic symptoms of the neck, especially dizziness. He stated that in many cases psychosomatosis was unjustly suspected, and that the symptoms could be resolved by the treatment of the neck muscles. In 1976, Braakman presented a literature review.5 He described possible injuries due to the ‘whiplash-mechanism’ and stated that after the signs of soft-tissue injuries had disappeared, physical treatment was contra-indicated and would only keep memories of the accident alive. He added that treatment in the chronic phase should emphasize on reassurance and if necessary confront the patient with his or her fear.

In a second ‘clinical lesson’, in 1981, Jongkees again presented his view on whiplash symptoms.6 Ten years later Van Wijngaarden described symptoms in 200 patients who were referred for an expert neurology assessment.7 In the same journal Kortbeek presented a review.8 In 1997, Ronnen et al. republished in Dutch their previously internationally published paper on the indications of MRI in cases of acute whiplash trauma.9,10 In a ‘clinical lesson’ in 2002, Reinders urged medical doctors to take psychological factors into account, and to use a bio-psychosocial model as an explanation for the complaints.11 In 2004, Vendrig et al. presented an overview of the current knowledge regarding prevention and treatment, based on published evidence.12

Of course there have also been many articles on neck pain published by Dutch authors in English, many of which are found in dissertations. Without striving for completeness a short overview is presented below.

The main focus of the thesis by Hoving (‘Neck pain in primary care’, 2001) was on the effectiveness of commonly applied interventions for patients with neck pain in primary care.13 A randomized clinical trial using the short and long-term outcomes of 183 patients with non-specific neck pain receiving either manual therapy, physical therapy or GP care was presented. Hoving concluded that manual therapy showed a beneficial effect compared to physical therapy and GP care.

The main objective of the thesis by Ariëns (‘Work-related risk factors for neck pain’, 2001) was to identify work-related physical and psychosocial risk factors for neck pain.14 The results of a large, three-year prospective cohort study in an occupational setting aiming to identify work-related risk factors for musculoskeletal complaints were reported.

13

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Introduction

The results showed a relationship between prolonged sitting and neck flexion, and neck pain. In addition, the results presented showed that high quantitative job demands, low job control (decision authority) and low co-worker support were also risk factors for neck pain.

Versteegen (‘Sprain of the neck & whiplash associated disorders’, 2001) studied epidemiological and other consequences of neck sprain and Whiplash Associated Disorders (WAD).15 In this thesis, data from 25 years of emergency room visits to the University Hospital Groningen due to neck sprain were studied. Over the 25-year study period a steady increase in patients with neck sprain was observed. Personal circumstances such as life-events and their relationship with the course of the complaints were also studied. Albeit suffering from a low response, it appeared that life-events did not play a role in the development of whiplash associated disorders.

The main aims of the thesis by Nederhand (‘Muscle activation patterns in post traumatic neck pain’, 2003) were to clarify the characteristics of ‘musculoskeletal signs’ in acute and chronic post-traumatic neck pain patients and to determine its clinical relevance in relation to the management of acute and chronic post-traumatic neck pain patients.16 The studies were the first to prospectively investigate the muscle activation patterns of acute neck pain, following patients until they recovered or developed chronic disability. The results did not demonstrate that these muscle activation patterns played a significant role in the transition from acute to chronic pain. Furthermore, it concluded that it was not the injury severity that determined the muscle activation pattern but rather the perception of the symptoms.

The general aim of the thesis by Scholten-Peters (‘Whiplash and its treatment’, 2004) was to gain insight into the effectiveness of a conservative treatment provided by general practitioners and physiotherapists for patients with whiplash associated disorder.17 Additionally, possible prognostic factors associated with poor recovery were also studied. Apart from systematic reviews of the effectiveness of conservative treatments and prognostic factors, a randomized clinical trial was also conducted, consisting of 150 patients, which compared GP care and physiotherapy. The study revealed no significant differences between the primary outcome measures of pain and work activities at 12 and 52 weeks after the accident.

The main aim of the thesis by Blokhorst (‘State-dependent factors and attention in Whiplash Associated Disorder’, 2005) was to investigate the relationship between state-dependent factors such as headache, neck pain, fatigue or distress and attention.18 It concluded that the health state of WAD patients is significantly related to attentional functioning. Treatment of chronic patients should therefore focus on pain as well as on stress management in the broadest sense, implying for example reduction of negative emotions (for example, post-traumatic stress symptoms, phobic reactions).

14

Chapter 1

The general aim of the thesis by Vos (‘Acute neck pain in general practice’, 2006) was to gain an insight into the clinical course of patients with acute neck pain once they had visited their general practitioner.19 In a prospective cohort study with a one-year follow-up the clinical courses of 187 patients with acute neck pain was studied. A subgroup analysis focused on 42 patients who had been involved in motor vehicle accidents (MVAs). This group showed higher levels of headache or neck pain and neck disability at baseline and follow-up, compared to neck pain patients not reporting a MVA. It was concluded that exposure to MVAs constitutes a relevant subgroup of patients in general practice with higher levels of continuous neck pain and disability.

Vangronsveld (‘By accident. Pain catastrophizing and fear of movement in patients with neck pain after a motor vehicle accident’, 2007) investigated the association between the fear-avoidance model and acute and persisting neck pain after a motor vehicle accident.20 Using different methodological designs, including theory-based predictive variables and measuring multiple outcome measures, the results revealed an intricate interplay between pain, anger and fear. Although some of the results were in favour of the Fear-Avoidance model, they also highlighted the importance of including all variables of the model in research since all of them may be of specific influence in different stages of pain. Although included for explorative reasons, baseline anger was the strongest predictor for the long-term outcomes, in terms of post-traumatic stress symptoms, but also for disability, depression and quality of life.

The thesis by Pool (‘Neck pain: “a pain in the neck”? A study of therapeutic modalities and clinimetrics’, 2007) presented an overview of interventions.21 Furthermore, the design and results of a randomized clinical trial comparing a behavioural graded activity programme with manual therapy for patients with non-specific sub-acute neck pain were reported. The results revealed a marginally but statistically significant difference on various outcome parameters in favour of the behaviour graded activity programme. It was concluded that there were only marginal, but not clinically relevant, differences between the two programmes studied. In a second, prospective study the prognostic value of psychological factors on short and long-term outcomes was investigated. No core set of prognostic psychological factors that predict the short and long-term outcomes of sub-acute neck pain could be identified. Finally, the Minimal Clinically Important Change (MCIC) on the Neck Disability Index (NDI) and the Numeric Rating Scale (NRS) for pain in patients with neck pain was assessed.

The primary objective of the thesis by Voerman (‘Musculoskeletal neck-shoulder pain. A new ambulant myofeedback intervention approach’, 2007) was to obtain insight into the effects and mechanisms of a new ambulant myofeedback intervention approach in patients with persistent neck and shoulder pain.22 It concluded that ambulant myofeedback training is beneficial in reducing neck and shoulder pain as well as disability in patients

15

1

Introduction

with complaints related to work or Whiplash Associated Disorder. Although the working mechanisms of myofeedback are not yet fully understood, cognitive behavioural factors are thought likely to be more important than muscle activation patterns. EpidemiologyThere are no reliable up-to-date figures on the epidemiology of whiplash in the Nether-lands. Wismans conducted an investigation into the incidence of whiplash in the Netherlands in 1994, with the goal of gaining insight into the problem of whiplash specifically in the Netherlands.23 The study included data from various sources, for example police and hospitals, the social security office, and motor vehicle and medical insurers. The data showed low incidence numbers from all sources except liability insurance company data. It was estimated that a total incidence of 15,000 to 30,000 new patients with whiplash per annum was plausible.

Versteegen et al. published incidence figures from the emergency room of the University Medical Center Groningen (UMCG) from 1970 to 1994.24 The incidence curve suggests an epidemic-like explosion in the number of emergency room visitors with neck sprain after a car accident, although the absolute numbers remained relatively low, with a maximum of 122 patients per year. However, unpublished data on UMCG emergency room visitors with neck sprain after 1994 show a dramatic decline in numbers, suggesting that the epidemic has abated. A recently published Dutch study which failed because of insufficient patients, confirms that the number of patients seeking help for cervical complaints after a motor vehicle accident seems to be rapidly declining in the Netherlands.25 However, everyday practice in the liability claims departments of insurers does not confirm this trend, although, again reliable nationwide figures do not exist.

A report by the Comité Europeén des Assurances (CEA) and the Association for the Study and Compensation of Bodily Injury (AREDOC) from 2004 shows that according to insurance companies the Dutch incidence of new minor cervical trauma claims is 20,000 per year.26 According to the CEA a rise in cervical injury claims was first noted in 1999. In the above-mentioned incidence curve of UMCG emergency room visitors, the largest incidence increase occurred 5 to 10 years before 1999, suggesting that claim incidence may show a delayed reaction.

Whiplash can be a cause of work disability. Within the Dutch social security system, employees are insured for long-term work disability by the WIA (WAO). Because of the privatization of the first two years of work disability since 2005, there are currently no data on diagnosis-related incidence figures in the first two years of disability. Earlier figures from the Social Security Office (UWV) show that in 2002, 1,473 new claims for long-term (> 1 year) work disability were granted and, in total, 43,523 (5.4%) work-disabled employees received compensation because of whiplash. There are no data on privately insured self-

16

Chapter 1

employed workers. All in all, the literature suggests that whiplash is a major problem in the Netherlands,

leading to a high number of work-disability and liability claims. Furthermore, there is some evidence that the epidemic of the early 1990s has reached its peak.

Research on Whiplash

The major body of research on whiplash focuses on complaint recovery. However, whiplash can also lead to long-term sick leave and the granting of disability pensions. Work is a functional outcome parameter and responsible for a major part of the socioeconomic costs of whiplash.27 Research has shown that the costs of sick leave and disability pensions are much higher than those of acute medical care, demonstrating that these parameters are of paramount importance when evaluating the consequences of neck pain after motor vehicle accidents.28

On several occasions whiplash has been compared to railway spine, a nineteenth-century complex of various complaints later labelled psychosomatic in nature.29,30 In railway spine, people experienced unexplained symptoms after railway accidents, and later after travelling in a train. Fear of train accidents were thought to have caused increased anxiety levels, giving rise to psychosomatic complaints fuelled by liability claims. Indeed the similarities are striking, making it painfully clear that we should learn the lessons of history to avoid repeating it. The history of post-traumatic neurosis proves to be very educational and a prerequisite for anyone wanting to understand whiplash.29

Several articles have addressed the apparent differences in epidemiological figures for whiplash and its associated symptoms across different countries. A study by Schrader et al. led to much discussion, while a later published and methodologically more profound study by Oubelieniene is often overlooked.31,32 Both studies investigated neck pain after traffic accidents in Lithuania. The findings suggested that in Lithuania there is no evidence of disabling or persistent symptoms as a result of car accidents. The main conclusion was that in a country where there is no preconceived notion of chronic pain arising from rear-end collisions, and thus no fear of long-term disability, and usually no involvement of the therapeutic community, insurance companies or litigation, whiplash symptoms are self-limiting, brief, and do not seem to evolve into a chronic syndrome. The studies gave rise to several articles and editorial comments regarding culture-dependent factors.

On reviewing the literature on whiplash it seems that it is apparently not a worldwide condition, but pertains mainly to some Western European countries, the US, Canada and Australia. Considering that accidents occur everywhere, this very fact suggests that the nature of the syndrome is culture-dependentSince 1945, when Davis initiated the large body of medical literature on whiplash, many

17

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Introduction

articles have been published on the subject. In 1995, the Quebec taskforce assessed about 10,000 articles on whiplash, and recently, in 2008 the ‘Bone and Joint Decade 2000–2010 Task Force on Neck Pain and Its Associated Disorders’ assessed 31,878 citations on neck pain, demonstrating that it is a major subject of research.2,33 However, a striking fact is the shear variation in the content of these articles. Along with articles on the relevance of head restraints, safety belts, or crash-related parameters, there are articles on anxiety, psychiatric symptoms and cultural aetiology, sometimes in the same journal. For a non-expert in the field the literature on whiplash must seem very confusing, and lacking a clear or uniform line or direction of research. This profound heterogeneity of the literature on whiplash is a sign of the widely different opinions regarding its aetiology and hence its prevention, diagnosis and treatment.

The literature on whiplash can roughly be divided into two research directions. The first can be described as the physical or somatic direction. This line of research looks for somatic signs or injuries which could possibly explain the persisting symptoms. There are many articles on the physical aspects of car crashes, looking for the car crash parameter or safety precaution which can predict or prevent the occurrence of whiplash complaints. Diagnostic procedures in search of a somatic injury are described. The interventions investigated are often invasive, ranging from manipulations or injections with various substances to extensive operations on cervical vertebrae. However, studies on somatic or physical predictors have not convincingly shown accident parameters, headrest use etc. to be reliable predictors. In a recent systematic review of physical prognostic factors it was concluded that the medical literature reviewed showed poor methodological quality, highlighting the need for better-quality research. However, the perceived pain was found to have a central role in the development of chronic complaints.34 In various studies, early neck pain severity is found to be associated with longer-term neck pain, for example, occurring after one year. Because no injury is identified that can explain the perceived pain and other complaints, the somatic perspective provides no clear view on the aetiology of symptoms.

The second research line is psychological in nature. It builds on the history of post-traumatic neurosis, and the large body of research on psychological principles in other chronic pain conditions such as low back pain. It includes articles on cultural aspects and the role of psychological parameters such as anxiety, depression and personality characteristics. This psychological line of research shows that various psychological variables seem relevant, although to date no single psychological parameter stands out as the cause of whiplash. In a recent systematic review of psychological factors it was concluded that self-efficacy and post-traumatic stress may be associated with chronic complaints, although again, lack of conclusive findings and the poor methodological quality of the studies reviewed highlights the need for better-quality research.35

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Chapter 1

Obviously, it should be ensured that two different syndromes or medical entities are not investigated under the same name. A car crash, or any accident for that matter, can result in an injury to the cervical spine. Investigation of the cervical spine is therefore standard procedure in any emergency room investigation after a car crash of sufficient energetic size. While there is no doubt that a car crash can lead to serious injury of the cervical spine, it is also obvious that not every patient with persisting complaints after a car crash has a cervical injury. Persisting symptoms can have many causes, and when an injury is ruled out, it is feasible to move on to other possible diagnoses. Some physicians and other health-care workers persistently concentrate on the physical aspects of whiplash complaints. Obviously, an injury can cause physical complaints, but this of course does not imply that all physical complaints are thus caused by an injury. Knowledge of the psychosomatic processes and the role of culture-related factors is of paramount importance when dealing with unexplained symptoms.36 Fortunately, increasing attention is being paid to the cultural and psychological aspects of physical complaints in medical curricula and education.

The evidently large differences between countries and the very low accident velocities that are often reported, with acceleration levels usually experienced in everyday life, nevertheless resulting in severe, long-lasting and incapacitating complaints, indicate that the physical aspects alone cannot explain all persisting symptoms.37-39 In this thesis therefore the focus of research is on psychological factors.

Psychological aspects of whiplash

In contrast to research on low back pain, a recent review of predictive factors for developing chronic whiplash complaints revealed only a limited predictive value for psychosocial variables.35,40 Other studies have reported that neither personality traits nor psychopathological symptoms can predict outcomes. However, these studies are known to have design and other methodological deficiencies that preclude them from effectively addressing the issue of psychological factors in a meaningful way.35,41,42

In research on low back pain it is well established that psychological factors are related to chronic pain and disability.43 Given the fact that in chronic whiplash there is also chronic musculoskeletal pain related to the spine without identification of a somatic cause, it seems reasonable to assume that psychological parameters can also play a role in the aetiology and course of persisting whiplash symptoms.

An important factor to consider is the fact that neck complaints in whiplash are caused, or at least experienced, after an accident. An accident is often a frightening or terrifying experience. That such an experience could lead to anxiety of any kind is not surprising. Considering the known influence of anxiety on somatic complaints, this alone

19

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Introduction

makes studying anxiety in relation to unexplained somatic symptoms very interesting. Dysfunctional coping styles could further fuel anxiety and psychosomatic mechanisms, thereby possibly leading to enhanced and a prolonged course of symptoms. Anxiety related to avoidance, such as in kinesiophobia or fear of (re)injury could play an important role, considering its apparent relevance in other chronic pain syndromes. Post-traumatic stress disorder is also a specific kind of anxiety related to the experience of a (life) threatening event. Since by definition the neck complaint occurs after an accident, there has been a potentially threatening event. It could be expected that the post-traumatic stress anxiety symptoms are related to the severity of the somatic complaints and could play a role in the prognosis of neck pain after a motor vehicle accident. The culture-dependent nature of whiplash also gives cause for discussion. Patients’ beliefs regarding the origin or cause of the complaints could be relevant considering the catastrophic interpretation that may be involved in the early negative expectations regarding the course and prognosis of neck pain after a motor vehicle accident.

CopingCoping can be defined as the way in which someone behaviourally, cognitively and emotionally adapts so as to manage external or internal stressors.44 The accident itself, as well as the pain afterwards, can be considered an external stressor and therefore as requiring coping efforts. Coping has been conceptualized in various ways, often dependent on the questionnaire used to index the construct.

The concept of coping has also been the subject of research in relation to chronic low back pain. The literature available shows an association between coping style and prognosis and outcome of treatment in low back pain.45;46 Furthermore, in whiplash the onset of complaints is often related to a stressful accident, which could put a higher demand on adequate coping skills. At the same time, the experience of neck pain can be much more frightening than low back pain, which is more common, and usually known to be benign in nature. Depending on the cultural context, acute neck pain can be associated with persistent complaints and disability, making the complaints an even more potentially terrifying experience. Dysfunctional coping styles could thus lead to enhanced pain experience or catastrophic interpretations of symptoms, thereby contributing to a bad prognosis.

Kinesiophobia & catastrophizingIn relation to low back pain, the fear-avoidance model was developed to provide an integrated model of the risk factors known to be associated with pain.47 Central to this model is the concept of the fear of pain. In this model, catastrophizing leads to pain-related fear, leading to avoidance behaviour, including the avoidance of movement and

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Chapter 1

physical activity. Studies suggest that an excessively negative orientation toward pain catastrophizing and fear of movement/(re)injury (kinesiophobia) are important in the aetiology of chronic symptoms.48 In low back pain, fear-avoidance beliefs are identified as risk factors for chronic low back pain, suggesting that these factors play a causal role.

Another interesting aspect of kinesiophobia is the fact that patients with chronic low back pain who retrospectively reported a sudden traumatic pain onset exhibited more kinesiophobia than patients who reported that the pain had started gradually.49 Since in the case of whiplash the onset of pain is often described as sudden, this may set the stage for developing kinesiophobia, which in turn may contribute to a chronic course.

Pain catastrophizing refers to an exaggerated negative orientation towards actual or anticipated pain.50 Earlier research has found that the habitual tendency to make catastrophic interpretations of pain is associated with a heightened pain experience in various patient groups.51 Furthermore, catastrophizing has been associated with heightened disability in chronic pain, independent of the level of actual physical impairment.52-54

Causal beliefs In the above-mentioned fear-avoidance model, the pathway from pain experience to fear, anxiety and avoidance, leading ultimately to disuse and disability, is moderated by catastrophizing and threatening illness beliefs. Causal illness beliefs can be defined as the patient’s ideas about the origin or cause of the symptoms or illness experienced.

The causal beliefs of the patient seem very relevant in relation to the persistence of complaints when no organic cause has been identified. When patients are diagnosed with an illness they generally develop an organized pattern of beliefs about their condition. These illness perceptions or cognitive representations directly influence behaviour parameters and the emotional response.55

In chronic fatigue syndrome, for example, it has been found that somatic illness beliefs are associated with increased symptoms and functional impairment, poorer subjective and objective outcomes and a poor prognosis.56,57 In somatoform disorders, organic causal attributions are associated with a need for medical diagnostic examinations, increased expression of complaints and body scanning.58 In addition, inadequate illness beliefs were found to be associated with heart-focused anxiety.59

From the literature on whiplash it can be deduced that there may be many different ideas about its cause held by health professionals and consequently patients. Causal beliefs lead to expectations regarding the course of complaints. Negative expectations could give rise to avoidant behaviour, leading to the avoidance of movement and physical activity, and ultimately leading to disuse and a heightened state of fear. When the cause of acute myogenic neck complaints is attributed to a severe, for example, neural

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Introduction

or irreparable cause, dysfunctional beliefs and expectations arise. Therefore, given the possible importance of causal attribution, dysfunctional beliefs may play an important role in the prognosis of whiplash.

In the large body of research on whiplash its cultural dependence is often the subject of discussion. The fact that whiplash only seems to occur in a restricted number of countries and runs an apparently different course in various countries seems to imply that the cultural context is a major factor to be considered.31,32,60,61 However, the actual nature of that cultural context has never been subject to research. Causal illness beliefs are shaped by cultural factors. Beliefs and expectations regarding whiplash were found to vary profoundly across countries, thereby providing a cultural parameter relevant to the prognosis of muscular neck pain.61-64

The medical interpretation and explanation of myogenic neck pain after a motor vehicle accident, provided by general practitioners or emergency room staff, as well as commonly held knowledge and culture-defined ideas, may give rise to dysfunctional illness beliefs regarding the cause of the neck complaints, which in turn may cause catastrophic expectations that lead to a chronic course.37

Additionally, it is conceivable that pain catastrophizing leads to more dysfunctional causal beliefs. The tendency to attribute neck complaints to irreparable or severe causes in its turn may elicit catastrophic interpretations of potentially benign muscular symptoms. Catastrophizing and dysfunctional causal beliefs could thus lead to a negative spiral, augmenting symptom severity and discharging into irrational expectations regarding the course of the symptoms and disability, fuelling a chronic course.47,65

Post-traumatic stress disorder Post-traumatic stress disorder is an anxiety disorder which consists of three symptom clusters: re-experiencing, avoidance and hyperarousal symptoms. Post-whiplash syndrome and post-traumatic stress disorder are both relatively common conditions following traffic accidents.66-68 As many as 23 percent of traffic accident victims are reported to have developed post-traumatic stress disorder, which is known to have high psychiatric and medical comorbidity.69-72

Earlier research has provided preliminary evidence to indicate that post-traumatic stress symptoms (that is, re-experiencing and avoidance symptoms) are related to whiplash.73-75 More specifically, the re-experiencing and avoidance subscales of the Impact of Event Scale were found to be associated with relatively persistent whiplash complaints at six month follow-up. Unfortunately, this study tested only two of the three post-traumatic stress disorder symptom scales; the hyperarousal symptom cluster scale was not included. Nonetheless, these hyperarousal symptoms may be highly relevant to the proper understanding of the relationship between post-traumatic stress disorder and

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Chapter 1

whiplash.76 An other study considered all three post-traumatic stress disorder symptom scales but recruited its participants solely from an emergency room, thereby possibly biasing the results towards patients who were more frightened or whose injuries were more serious.77

Since anxiety is an important feature of post-traumatic stress disorder and is known to influence the perception and experience of pain, post-traumatic stress symptoms may alter the perception and experience of acute neck pain.78 Post-traumatic stress symptoms may give rise to increased anxiety and vigilance levels, thereby fuelling catastrophic, dysfunctional interpretations of acute neck pain. Finally, post-traumatic stress disorder shares several symptoms with whiplash, including insomnia, irritability and cognitive problems. Therefore it is also conceivable that post-traumatic stress symptoms are erroneously attributed to whiplash.

Outline of the thesisIn this thesis five descriptive studies will be presented that are cross-sectional and (prospective) longitudinal in nature. The general aim of these studies is to determine the consequences of whiplash for work disability and the relationship between psychological parameters and the prognosis.

Traffic accident victims who had initiated compensation claim procedures for personal injury with a Dutch insurance company were asked to participate in the various studies. The letter of invitation clearly communicated that the study was independent of the compensation procedure. Participants were assessed at one, six and twelve months after their accident using relevant questionnaires. Because of the available cross-sectional data, subgroups could be analysed at any of the three moments. The longitudinal data could be used to analyse predictive characteristics and the temporal order of events. To keep the total number of questionnaires small, different samples were used for each study, with the exception of the study on work disability (Chapter 2), in which the sample was formed by combining the other four.

Following this introductory chapter, Chapter 2 of this dissertation will present a study on whiplash and work disability. In a prospective cohort study, the symptoms and work-related factors from 879 participants with neck pain after a motor vehicle accident were investigated and followed up after six and twelve months. The relationship between whiplash, its symptoms and work characteristics will be analysed and described.

In Chapter 3, a prospective cohort study of 363 participants with neck pain after a motor vehicle accident, will be described, with a follow-up of one year. Coping styles employed within the first month will be investigated and the associations with the course of physical and cognitive symptoms studied.

One of the concepts derived from the fear-avoidance model is kinesiophobia, or fear of

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Introduction

movement and (re)injury. In Chapter 4, we will describe a prospective cohort study of 367 participants with neck pain after a motor vehicle accident. The predictive value of early kinesiophobia in relation to the course of whiplash symptoms will be studied.

Chapter 5 contains a prospective cohort study of 240 participants with neck pain after a motor vehicle accident. The relationship between post-traumatic stress disorder and its symptoms, and the severity and course of whiplash at one, six and twelve months will be studied.

In Chapter 6, a prospective cohort study of 140 participants with neck pain after a motor vehicle accident will be presented. Early pain catastrophizing and causal beliefs in relation to the severity and prognosis of whiplash will be investigated.

Finally, in Chapter 7 the results of the various studies will be integrated and discussed.

24

Chapter 1

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37. Ferrari R. Whiplash cultures. CMAJ. 1999;161:368.

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39. Ferrari R, Russell AS. Epidemiology of whiplash: an international dilemma. Ann.Rheum.Dis. 1999;58:1-5.

40. Scholten-Peeters GG, Verhagen AP, Bekkering GE, van der Windt DA, Barnsley L, Oostendorp RA et al. Prognostic factors of whiplash-associated disorders: a systematic review of prospective cohort studies. Pain 2003;104:303-22.

41. Borchgrevink GE, Stiles TC, Borchgrevink PC, Lereim I. Personality profile among symptomatic and recovered patients with neck sprain injury, measured by MCMI-I acutely and 6 months after car accidents. J.Psychosom.Res. 1997;42:357-67.

42. Radanov BP, Di Stefano G, Schnidrig A, Ballinari P. Role of psychosocial stress in recovery from common whiplash [see comment]. Lancet 1991;338:712-5.

43. Linton SJ. Do psychological factors increase the risk for back pain in the general population in both a cross-sectional and prospective analysis? Eur.J.Pain 2005;9:355-61.

44. Folkman S, Lazarus RS, Dunkel-Schetter C, DeLongis A, Gruen RJ. Dynamics of a stressful

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encounter: cognitive appraisal, coping, and encounter outcomes. J.Pers.Soc.Psychol 1986;50:992-1003.

45. Wessels T, Tulder M.van, Sigl T, Ewert T, Limm H, Stucki G. What predicts outcome in non-operative treatments of chronic low back pain? A systematic review. Eur.Spine J. 2006;15:1633-44.

46. van der HM, Vollenbroek-Hutten MM, IJzerman MJ. A systematic review of sociodemographic, physical, and psychological predictors of multidisciplinary rehabilitation-or, back school treatment outcome in patients with chronic low back pain. Spine 2005;30:813-25.

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48. Picavet HS, Vlaeyen JW, Schouten JS. Pain catastrophizing and kinesiophobia: predictors of chronic low back pain. Am.J.Epidemiol. 2002;156:1028-34.

49. Crombez G, Vlaeyen JW, Heuts PH, Lysens R. Pain-related fear is more disabling than pain itself: evidence on the role of pain-related fear in chronic back pain disability. Pain 1999;80:329-39.

50. Sullivan MJ, Pivik J. The Pain Catastrophizing Scale: Development and Validation. Psychol Assess 1995;7:524-32.

51. Sullivan MJ, Thorn B, Haythornthwaite JA, Keefe F, Martin M, Bradley LA et al. Theoretical perspectives on the relation between catastrophizing and pain. Clin.J.Pain 2001;17:52-64.

52. Sullivan MJ, Stanish W, Waite H, Sullivan M, Tripp DA. Catastrophizing, pain, and disability in patients with soft-tissue injuries. Pain 1998;77:253-60.

53. Sullivan MJ, Stanish W, Sullivan ME, Tripp D. Differential predictors of pain and disability in patients with whiplash injuries. Pain Res.Manag. 2002;7:68-74.

54. Severeijns R, Vlaeyen JW, van den Hout MA, Weber WE. Pain catastrophizing predicts pain intensity, disability, and psychological distress independent of the level of physical impairment. Clin.J.Pain 2001;17:165-72.

55. Petrie KJ, Weinman J. Why Illness Perceptions Matter. Clinical Medicine 2007;6:536-9.

56. Vercoulen JH, Swanink CM, Fennis JF, Galama JM, van der Meer JW, Bleijenberg G. Prognosis in chronic fatigue syndrome: a prospective study on the natural course. J.Neurol.Neurosurg.Psychiatry 1996;60:489-94.

57. Butler JA, Chalder T, Wessely S. Causal attributions for somatic sensations in patients with chronic fatigue syndrome and their partners. Psychol Med. 2001;31:97-105.

58. Rief W, Nanke A, Emmerich J, Bender A, Zech T. Causal illness attributions in somatoform disorders: associations with comorbidity and illness behavior. J.Psychosom.Res. 2004;57:367-71.

59. Eifert GH, Hodson SE, Tracey DR, Seville JL, Gunawardane K. Heart-focused anxiety, illness beliefs, and behavioral impairment: comparing healthy heart-anxious patients with cardiac and surgical inpatients. J.Behav.Med. 1996;19:385-99.

60. Giebel GD, Bonk AD, Edelmann M, Huser R. Whiplash injury. J.Rheumatol. 1999;26:1207-8.

61. Partheni M, Constantoyannis C, Ferrari R, Nikiforidis G, Voulgaris S, Papadakis N. A prospective cohort study of the outcome of acute whiplash injury in Greece. Clin.Exp.Rheumatol. 2000;18:67-70.

62. Ferrari R, Lang C. A cross-cultural comparison between Canada and Germany of symptom expectation for whiplash injury. J.Spinal Disord.Tech. 2005;18:92-7.

63. Ferrari R, Constantoyannis C, Papadakis N. Laypersons’ expectation of the sequelae of whiplash injury: a cross-cultural comparative study between Canada and Greece. Med.Sci.Monit. 2003;9:CR120-CR124.

27

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64. Ferrari R, Obelieniene D, Russell A, Darlington P, Gervais R, Green P. Laypersons’ expectation of the sequelae of whiplash injury. A cross-cultural comparative study between Canada and Lithuania. Med.Sci.Monit. 2002;8:CR728-CR734.

65. Leeuw M, Goossens ME, Linton SJ, Crombez G, Boersma K, Vlaeyen JW. The Fear-Avoidance Model of Musculoskeletal Pain: Current State of Scientific Evidence. J.Behav.Med. 2006.

66. Brom D, Kleber RJ, Hofman MC. Victims of traffic accidents: incidence and prevention of post-traumatic stress disorder. J.Clin.Psychol. 1993;49:131-40.

67. Mayou RA. Psychiatric consequences of motor vehicle accidents. Psychiatr.Clin.North Am. 2002;25:27-41, vi.

68. Mayou RA, Black J, Bryant B. Unconsciousness, amnesia and psychiatric symptoms following road traffic accident injury. Br.J.Psychiatry 2000;177:540-5.

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70. Blanchard EB, Hickling EJ, Freidenberg BM, Malta LS, Kuhn E, Sykes MA. Two studies of psychiatric morbidity among motor vehicle accident survivors 1 year after the crash. Behav.Res.Ther. 2004;42:569-83.

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73. Drottning M, Staff PH, Levin L, malt UF. Acute emotional response to common whiplash predicts subsequent pain complaints. Nord J Psychiatry 1995;49:293-9.

74. Sterling M, Kenardy J, Jull G, Vicenzino B. The development of psychological changes following whiplash injury. Pain 2003;106:481-9.

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76. Jaspers JP. Whiplash and post-traumatic stress disorder. Disabil.Rehabil. 1998;20:397-404.

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78. Chibnall JT, Duckro PN. Post-traumatic stress disorder in chronic post-traumatic headache patients. Headache 1994;34:357-61.

29

Work disability after whiplash: a prospective cohort study

J. Buitenhuis, P.J. de Jong, J.P.C. Jaspers, J.W. Groothoff

Published in: Spine 2009;34(3):262-7

2

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Chapter 2

Abstract

Study Design, Objective: Prospective cohort studyThis study investigates the consequences of neck pain after motor vehicle accidents in terms of disability for work and the relationship this has with symptom and work-related factors.

Summary of Background Data: Previous studies on work disability related to whiplash are very heterogeneous, are often limited in sample size and show a wide variability in terms of results. A relationship between poor recovery from or persistent work disability after whiplash, and female gender, older age, marital status, heavy manual work, self-employment, prior psychological problems, subjective complaints of poor concentration, pain catastrophizing and kinesiophobia has been suggested.

Methods: Individuals with neck complaints after involvement in traffic accidents, who initiated compensation claim procedures with a Dutch insurance company (n=879), were sent questionnaires (Q1) concerning the accident, the injuries that they had sustained, their complaints at that time and questions regarding work and disability. The course of complaints and work disability was monitored at six months (Q2) and twelve months (Q3) after the accident.

Results: A total of 58.8% of the population with neck complaints studied was work-disabled after the accident.Age and impaired concentration complaints after one month were found to be related to work disability at one year, independent of physical complaints and work characteristics.

Conclusions: Age and concentration complaints were important independent predictors of long-lasting work disability, whereas no evidence emerged to indicate that the degree of manual labor (blue or white collar work) or educational level was involved in persistent work disability in post-whiplash syndrome. The current results suggest that work disability could benefit most from interventions related to recovery from cognitive complaints and less from physically related interventions.

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2


Introduction

Distorsion or strain of the neck due to sudden movement of the head, is a prevalent injury following a motor vehicle accident. Following the original specific injury mechanism during a classic rear-end collision, accompanied by acceleration-deceleration and the whip-like movement of the head, this became known as whiplash. Nowadays, a specific injury mechanism is no longer considered a prerequisite, and any case with strain of the neck after an accident of any kind can be labeled as whiplash.1 Muscular symptoms of strain of the neck usually heal in days to weeks. Persistent neck complaints, sometimes accompanied by cognitive complaints, are known as post-whiplash syndrome or Whiplash Associated Disorder (WAD). The persistent complaints have become a major medical problem, and source of a large body of research and polemic discussions.1,2

Research has shown that up to 40% of neck complaints may become chronic and persist for at least a year.3 There is a vast amount of research concerning the incidence and course of complaint-related variables.2 However, whiplash can also lead to long-term sick leave and the granting of disability pensions, the increased socio-economic significance of which is only barely known.4 Research has shown that sick leave and disability pension costs are much higher than the costs of acute medical care, demonstrating that these parameters are of paramount importance when evaluating the consequences of neck pain after motor vehicle accidents.5 Furthermore, work disability could also be an important factor contributing to the persistence of complaints. Yet, work disability and related factors after whiplash have received only scant attention in previous research.6

The previous studies on work disability related to whiplash are very heterogeneous, often limited in sample size, and they show a wide variability in results. Some studies report full or nearly full return-to-work numbers, or limited time of work suggesting that work disability after whiplash is only a minor problem.1,6-11 On the other hand, other studies showed prolonged disability to be a major problem following whiplash.12-14

It is clear that, although some studies describe no or a limited duration of work disability following whiplash, it is evident that large discrepancies exist, most probably due to dissimilarities in studied populations and different definitions of (return to) work and work disability.

Furthermore only a limited number of studies investigated potentially underlying factors related to “return to work” and “persistent work disability” that may help explain the apparent discrepancies in the literature concerning the consequences of whiplash. To

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Chapter 2

summarize, previous research suggests that the factors of female gender, older age, heavy manual work and self-employment are related to poor recovery from or persistent work disability after whiplash.1,5,9,12

In light of the current discrepancies and the fact that sick leave and disability pension costs form a substantial part of the overall costs, this study investigates prevalence and course of work disability in whiplash, focusing on the relationship between whiplash-related complaints, work characteristics and work disability. The purpose of the current study is to analyze the consequences of neck pain after motor vehicle accidents in terms of disability for work and the relationship that this has with symptoms and work-related factors.

Methods

Study designVictims of car accidents, who had initiated compensation claim procedures at a Dutch

insurance company and who had presented themselves with neck complaints, were invited to participate. The study used a prospective longitudinal design. Participants were assessed at one (Q1), six (Q2) and twelve months (Q3) after their accidents.

Participants and procedureTraffic-accident victims, who had initiated compensation claim procedures for

personal injury with a Dutch insurance company, were asked to participate in this study. In the Netherlands, the settlement of personal injury claims is based on liability insurance, with the accident victims seeking compensation from the insurance company of the driver at fault. The letter of invitation clearly communicated that the present study was independent of the compensation procedure.

In the Netherlands there is a social security system. Employees receive, for at least one year, at least 70% of their salary when becoming work disabled. Self-employed would have to be self-insured to receive a compensation when becoming work disabled.

During the total intake period, 3752 questionnaires were dispatched. The total number of initial questionnaires returned was 2295 (61.2%). In line with our previous studies, a total of 879 eligible responses, consisting of participants between 18 and 65 years of age, motor vehicle occupants following an accident that caused neck complaints and soft tissue injuries only, with no history of chronic pain and no self-reported loss of consciousness longer than one minute, were included and used for further analyses.15-17

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Table 1. Basic characteristics of the assessment points in the studied sample.

Neck complaints at:

Q0 (accident) Q1 Q2 Q3 Variable N = 879 n = 728 n = 448 n = 384

Age, years, mean (sd) 36.4 (12.2) 36.5 (12.3) 36.9 (12.1) 37.4 (12.3)Male gender, n (%) 340 (38.7) 271 (37.2) 159 (35.5) 136 (35.4)Employment No work, n (%) 143 (16.3) 119 (16.3) 80 (17.9) 70 (18.2)

Paid employment, n (%) 702 (80.1) 578 (79.4) 346 (77.2) 292 (76) Working hours, mean (sd) 32.7 (22.2) 32.4 (12.0) 32.2 (12.1) 32.1 (12.3)

Blue collar, n (%) 411 (58.5) 345 (59.7) 213 (61.6) 179 (61.3) White collar, n (%) 289 (41.2) 231 (40.0) 132 (38.2) 112 (38.4) Unknown, n (%) 2 (0.3) 2 (0.3) 1 (0.3) 1 (0.3)

Self-employed, n(%) 31 (3.5) 29 (4.0) 20 (4.5) 20 (5.2) Working hours, mean (sd) 47.7 (11.9) 47.7 (16.6) 49.1 (14.0) 49.1 (14.0)

Blue collar, n (%) 20 (64.5) 20 (69.0) 17 (85.0) 17 (85) White collar, n (%) 8 (25.8) 7 (24.1) 2 (10.0) 2 (10) Unknown, n (%) 3 (9.7) 2 (6.9) 1 (5.0) 1 (5)

Work education (minimal level of education for described work) Unknown, n (%) 68 (7.7) 55 (7.6) 38 (8.5) 36 (9.4) Primary school, n (%) 90 (10.2) 75 (10.3) 51 (11.4) 43 (11.2) Lower sec. vocational, n (%) 398 (45.3) 336 (46.2) 207 (46.2) 175 (45.6) Senior sec. vocational, n (%) 219 (24.9) 185 (25.4) 115 (25.7) 97 (25.3) Higher education, n (%) 89 (10.1) 66 (9.1) 32 (7.1) 28 (7.3) University, n (%) 15 (1.7) 11 (1.5) 5 (1.1) 5 (1.3)

Neck pain intensity,a mean (sd) 6.1 (2.3) 6.6 (2.1) 6.7 (2.1)Neck stiffness,a mean (sd) 5.9 (2.6) 6.3 (2.5) 6.4 (2.5)Severity of restrictedneck movements,a mean (sd) 4.7 (2.4) 5.2 (2.3) 5.3 (2.3)Radiating pain in arms,a mean (sd) 3.2 (2.7) 3.8 (2.9) 3.4 (2.9)Pareasthesia,a mean (sd) 2.7 (2.6) 3.1 (2.7) 3.2 (2.8)Concentration complaints,a mean (sd) 3.9 (3.0) 4.5 (3.0) 4.6 (3.0)Headache intensity,a mean (sd) 4.9 (2.9) 5.5 (2.8) 5.5 (2.7)Dizziness, yes (%) 417 (57.3) 294 (65.6) 258 (67.2)Use of medication, yes (%) 399 (54.8) 278 (62.1) 239 (62.2)

a: 10 point scale; 0=no complaints, 10=severe complaints

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Chapter 2

Questionnaires and outcome variablesAfter a median time of 21 days after the accident (mean=23.7 days, S.D.=13.0) we sent

each claimant a questionnaire (Q1) concerning the accident, the injuries that they had sustained, their complaints at that time, and questions regarding work and disability. We monitored the course of the complaints and work disability at six months (Q2) and twelve months (Q3) after the accident. Table 1 gives an overview of the general items on the questionnaires.

Work disabilityAll self-reported job descriptions were classified in terms of physically demanding

labor (blue collar) and administrative or managerial work (white collar). Additionally, the minimal level of education of each job description was determined (primary school, lower or senior secondary vocational, higher or university education). Furthermore, the status in terms of self-employment or paid employment was determined. Self-reported work disability, working fewer hours because of reported complaints, was translated into a dichotomous variable for each assessment point to indicate work disability.

AnalysisStatistical analyses were conducted using SPSS version 14. Categorical variables were

recoded into appropriate dummy variables before they were used in the regression analysis.

Results

Of the 879 eligible participants with neck complains after the accident, 728 (82.8%) still had neck complaints at Q1, 448 (51.0%) at Q2, and 384 (43.7%) had persistent neck complaints at Q3. Of the 879 eligible participants, 70 (8.0%) did not return the questionnaire at Q2, and 47 (5.3%) did not return the third questionnaire. Table 1 provides an overview of the basic characteristics of participants with persistent neck complaints at the three assessment points.

The 733 participants with neck complaints after the accident, and who were involved in paid work (either paid employment or self-employed), were further analyzed regarding work disability.

In this group, 341 (46.5%) (16 of whom were self-employed) did not suffer from work disability. Furthermore, 141 (19.2%) participants were work-disabled, but had recovered before the first questionnaire was filled out. Four participants were work-disabled at Q1,

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2


but had recovered from neck complaints, and were therefore excluded. A total of 247 (33.7%) were work-disabled at Q1, 138 (18.9%) at Q2, and 92 (12.6%) were work-disabled at Q3. Table 2 provides an overview of work characteristics for these groups.

Table 2. Characteristics of work in participants with persistent work disability from Q1 Work-disabled at Q1 Q2 Q3 N = 247 (33.7%) n = 138 (18.9%) n = 92 (12.6%)

Paid employment, n (%) 234 (94.7) 129 (93.5) 85 (92.4)Working hours, mean (sd) 32.6 (11.8) 32.1 (11.9) 33.7 (12.0)

Blue collar, n (%) 152 (65.0) 78 (60.5) 51 (60)White collar, n (%) 82 (35.0) 51 (39.5) 34 (40)Unknown, n (%) 0 (0) 0 (0) 0 (0)

Self-employed, n (%) 13 (5.3) 9 (6.5) 7 (7.6)Working hours, mean (sd) 46.5 (9.9) 47.2 (8.7) 45.0 (10.4)

Blue collar, n (%) 10 (76.9) 7 (77.8) 6 (85.7)White collar, n (%) 2 (15.4) 1 (11.1) 0 (0)Unknown, n (%) 1 (7.7) 1 (11.1) 1 (14.3)

Analyses revealed no significant difference between participants who were self-employed or who had paid employment regarding work disability after the accident (Χ2=0.288, df=1, P=0.591), and work disability at Q1 (Χ2=3.622, df=1, P=0.057), Q2 (Χ2=3.728, df=1, P=0.053) and Q3 (Χ2=2.185, df=1, P=0.139), although the differences at Q1 and Q2 showed borderline significance.

Work disability and concurrent variablesThe relationship among work characteristics, concurrent complaints and work disability

at one (Q1), six (Q2) and twelve (Q3) months was further investigated. The univariate analysis of work disability at Q1 is presented in Table 3. The significant variables were used in a multiple logistic regression analysis, the results of which are presented in Table 4. Results show that work disability at Q1 is independently associated with higher neck pain intensity, more severe restriction of neck movements, more intense concentration complaints and consumption of medication at Q1.

Similar analyses were conducted for concurrent complaints and work disability at Q2 and Q3. The results for Q2 revealed that work disability at Q2 was independently

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Chapter 2

Table 3. Univariate analysis of the relationship between work characteristics and concurrent com-plaints, and work disability due to post-whiplash syndrome at Q1 Coeffi S.E. Wald Χ2 P value Odds 95% CI cient (β) ratio Lower Upper

Age -0.004 0.008 0.256 0.613 0.996 0.982 1.011 Gender 0.139 0.169 0.677 0.411 1.149 0.825 1.601 Work class Blue/white collar 0.381 0.172 4.909 0.027 1.463 1.045 2.049 Work educationa -0.106 0.101 1.105 0.293 0.899 0.738 1.096 Employment -0.178 0.383 0.215 0.643 0.837 0.395 1.773 Neck pain intensity 0.398 0.044 81.714 <0.001 1.489 1.366 1.624

Neck stiffness 0.221 0.035 39.723 <0.001 1.248 1.165 1.336 Severity of restricted neck movements 0.310 0.039 62.601 <0.001 1.363 1.263 1.472 Radiating pain in arms 0.208 0.032 41.525 <0.001 1.231 1.156 1.311 Pareasthesia 0.153 0.033 21.914 <0.001 1.165 1.093 1.242 Concentration complaints 0.268 0.031 74.124 <0.001 1.307 1.230 1.390 Headache intensity 0.215 0.032 46.595 <0.001 1.240 1.166 1.320 Dizziness 0.969 0.175 30.680 <0.001 2.634 1.870 3.712 Use of medication 1.083 0.174 38.809 <0.001 2.953 2.101 4.152

Univariate logistic regression. Work disability at Q1 used as dependent variable. Variables from Q1. a: recoded into dummy variables because of non-significance, mean results presented.

associated with concurrent neck pain intensity (odds ratio=1.302, 95% CI=1.098-1.544) and concentration complaints (odds ratio=1.337, 95% CI=1.210-1.478) at Q2.

At Q3 only concurrent concentration complaints (odds ratio=1.404, 95% CI=1.237-1.593) were significantly related to work disability, independent of other physical complaints and work characteristics.

Work disability and predictive variablesTo investigate the predictive value of investigated variables for continued work

disability at six and twelve months, we conducted a second analysis using the group with work disability at Q1. First, a univariate analysis was performed using variables from Q1 as independent variables, and work disability at Q2 as a dependent variable, which yielded similar significant variables as presented in Table 3, with the exception of work class, which was not significant, and age, which now was found to be significantly related to work disability at Q2. Table 5 shows the results of a multiple logistic regression analysis using the significant variables from the univariate analysis. Results reveal that work disability at Q2 is independently associated with relatively intense concentration complaints at Q1, with higher age and headache intensity showing borderline significance.

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Table 4. Multiple logistic regression model of significant work characteristics, concurrent com-plaints and work disability due to post-whiplash syndrome at Q1 Coeffi S.E. Wald Χ2 P value Odds 95% Cl cient (β) ratio Lower Upper Work Class 0.203 0.198 1.055 0.304 1.226 0.831 1.807 Neck pain intensity 0.236 0.061 14.986 <0.001 1.266 1.124 1.427

Neck stiffness -0.057 0.052 1.210 0.271 0.945 0.853 1.046 Severity of restricted neck movements 0.145 0.055 6.884 0.009 1.156 1.037 1.288 Radiating pain in arms 0.065 0.049 1.750 1.186 1.068 0.969 1.176 Pareasthesia -0.064 0.050 1.657 0.198 0.938 0.850 1.034 Concentration complaints 0.155 0.037 17.119 <0.001 1.167 1.085 1.256 Headache intensity -0.004 0.042 0.010 0.921 0.996 0.917 1.081 Dizziness 0.407 0.209 3.780 0.052 1.503 0.997 2.265 Use of medication 0.460 0.206 4.956 0.026 1.584 1.057 2.374

Variables from Q1. Work disability at Q1 used as dependent variable.

Table 5. Multiple logistic regression model of significant work characteristics, complaints at Q1 and work disability due to post-whiplash syndrome at Q2 Coeffi S.E. Wald Χ2 P value Odds 95% Cl cient (β) ratio Lower Upper

Age 0.019 0.011 3.395 0.065 1.020 0.999 1.041 Neck pain intensity 0.095 0.070 1.831 0.176 1.099 0.958 1.261 Neck stiffness -0.088 0.061 2.086 0.149 0.916 0.813 1.032 Severity of restricted neck movements 0.048 0.065 0.560 0.454 1.050 0.925 1.191 Radiating pain in arms 0.030 0.056 0.292 0.589 1.031 0.923 1.151 Pareasthesia 0.079 0.057 1.963 0.161 1.083 0.969 1.210 Concentration complaints 0.224 0.043 26.520 <0.001 1.251 1.149 1.362 Headache intensity 0.091 0.051 3.175 0.075 1.095 0.991 1.211 Dizziness 0.180 0.259 0.484 0.487 1.197 0.721 1.987 Use of 0.350 0.249 1.976 0.160 1.419 0.871 2.312


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Finally, analyses using variables from Q1 and work disability at Q3 were performed. Univariate analyses again indicated that age was significant as related to work disability at Q3. In contrast with the results presented in Table 3, work class and neck stiffness at Q1 were not significantly related to work disability at Q3. Table 6 shows the results of a multiple logistic regression analysis using the significant variables. Results reveal that work disability at Q3 is independently associated with higher age and more concentration complaints at Q1, independent of other physical complaints at Q1 and work characteristics.

To test this finding further, we added the interaction between combined complaint severity and work class, as well as the interaction between concentration complaints and work class as independent variables to the regression model presented in Table 6, showing no significant interaction.

Discussion

Our results show that work disability due to post-whiplash syndrome after a motor vehicle accident is a common problem. A total of 58.8% of the studied population with neck complaints was work-disabled after the accident. However, the vast majority of this group recovered from work disability in the first year: 31.3% in the first month, 66.7% in the first six months, and 78.3% in the first year, leaving 21.7% participants with persistent

Table 6. Multiple logistic regression model of significant work characteristics, complaints at Q1 and work disability due to post-whiplash syndrome at Q3 Coeffi S.E. Wald Χ2 P value Odds 95% CI cient (β) ratio Lower Upper

Age 0.028 0.012 5.264 0.022 1.028 1.004 1.052 Neck pain intensity 0.060 0.082 0.541 0.462 1.062 0.904 1.248 Severity of restricted neck movements -0.082 0.066 1.543 0.214 0.922 0.810 1.048 Radiating pain in arms 0.005 0.065 0.006 0.937 1.005 0.886 1.141 Pareasthesia 0.074 0.064 1.324 0.250 1.077 0.949 1.222 Concentration complaints 0.217 0.049 19.437 <0.001 1.242 1.128 1.368 Headache intensity 0.068 0.060 1.268 0.260 1.070 0.951 1.204 Dizziness 0.446 0.315 2.010 0.156 1.562 0.843 2.895 Use of medication 0.391 0.299 1.718 0.190 1.479 0.824 2.655


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work disability after one year (12.6% of the individuals with initial neck complaints), which is in line with the reported 12% return from work disability in the first year reported in the previous research by Kasch et al. However, it is much lower than the 44% reported by Holm et al., most probably due to population differences.10,12

Our univariate analysis shows several factors, especially those related to physical complaints, to be related to concurrent work disability. Even more relevant, the multiple regression models reveal that in the first month physical factors such as higher neck pain intensity, more restricted neck movements and use of medication, are independently related to work disability, together with impaired concentration. At six months, concurrent higher neck pain intensity and more concentration complaints were found to be related to persistent work disability. In line with previous research, concentration complaints were found to be related to concurrent work disability at twelve months.8

Although one might expect disability for white collar work to be more affected by concentration problems, our results surprisingly show that prolonged work disability is related to concentration complaints independent of the degree of manual labor (blue or white collar work) or level of education. Apparently, concentration complaints affect the ability to work regardless of the level of manual labor or level of education. In contrast with previous research, we found neither self-employment nor gender to be a significant predictive factor related to work disability.5,9

Regarding the analysis of the predictive value of parameters, age and impaired concentration complaints were found to be the only factors available at one month that were related to work disability at one year, independent of physical complaints and work characteristics. The intensity of concentration complaints could be an indication of depressive or anxiety symptoms. It would, therefore, be important for future research to investigate whether anxiety or depressive symptoms are indeed related to persistent work disability. The current results suggest that work disability could benefit most from interventions related to recovery from cognitive complaints and less from physically related interventions.

Although the relevance of age in regard to functional recovery from post-whiplash syndrome is a subject of discussion, our results clearly sustain the view that prolonged work disability is most pronounced in higher age groups.2

Interestingly, previous research consistently found early neck pain intensity to be a

main factor related to recovery after one year.15-17 Our results indicate that this is not the case for work disability, indicating that the prediction of functional outcome parameters,

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although being more relevant in regard to overall costs, cannot readily be deduced from research on complaint-related recovery.

Some comments regarding the limitations of this study are in order.The study group consisted of participants who had initiated compensation claim

procedures. However, since the threshold for starting such procedures is low in the Netherlands, there seems to be no strong reason to suspect that this introduced a bias toward patients whose complaints were more serious.18

The damage-report forms that are used for claiming car damage, and which are usually completed within a few days after the accident, contain a section for the names of victims and their complaints. We directly invited all claimants from these forms, including victims who had not visited an emergency room or sought medical help at the time of the accident; this, thereby, prevented a selection based on medical help-seeking.

Furthermore, although the insurance company and victims can be seen as opposing parties, most personal injury claims in the Netherlands, even large ones that involve serious injuries, are settled out of court. None of the participants was involved in actual litigation. Nevertheless, some studies have recently found that compensation is a critical factor to be considered when studying post-whiplash syndrome. Therefore, the personal injury claimant context should be taken into account when interpreting or generalizing our findings.19

Compensation data or pensions for work disability data are very difficult to compare across various countries. Comparison is hampered by differences in the instruments used, the timing of measurements, the inclusion criteria and the different definitions of work disability. Furthermore, work disability and especially work compensation, which is often used as an indication of work disability, is determined very differently in various countries due to different social security systems or disability pensions.

As most other studies using compensation or disability pension data have done, we similarly determined work disability, therefore, on the basis of self-report questionnaires. However, it should be acknowledged that any questionnaire-based data holds a risk of self-report bias.

In sum, this study clearly showed that work disability due to post-whiplash syndrome is not only a common problem, but also that in a considerable number of cases work disability takes a chronic course. Age and concentration complaints were identified as important independent predictors of such long-lasting work disability, whereas no evidence emerged to indicate that the degree of manual labor (blue or white collar work) or educational level was involved in persistent work disability in post-whiplash syndrome.

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References

1. Spitzer WO, Skovron ML, Salmi LR et al. Scientific monograph of the Quebec Task Force on Whiplash-Associated Disorders: redefining ”whiplash” and its management. Spine 1995;20:1S-73S.

2. Scholten-Peeters GG, Verhagen AP, Bekkering GE et al. Prognostic factors of whiplash-associated disorders: a systematic review of prospective cohort studies. Pain 2003;104:303-22.


4. Borchgrevink GE, Lereim I, Royneland L et al. National health insurance consumption and chronic symptoms following mild neck sprain injuries in car collisions. Scand.J.Soc.Med. 1996;24:264-71.


6. Athanasou JA. Return to work following whiplash and back injury: a review and evaluation. Med.Leg.J. 2005;73:29-33.

7. Maimaris C, Barnes MR, Allen MJ. ‘Whiplash injuries’ of the neck: a retrospective study. Injury 1988;19:393-6.

8. Radanov BP, Sturzenegger M, Di Stefano G. Long-term outcome after whiplash injury. A 2-year follow-up considering features of injury mechanism and somatic, radiologic, and psychosocial findings. Medicine (Baltimore) 1995;74:281-97.

9. Gozzard C, Bannister G, Langkamer G et al. Factors affecting employment after whiplash injury. J.Bone Joint Surg.Br. 2001;83:506-9.

10. Kasch H, Bach FW, Jensen TS. Handicap after acute whiplash injury: a 1-year prospective study of risk factors. Neurology 2001;56:1637-43.

11. Richter M, Ferrari R, Otte D et al. Correlation of clinical findings, collision parameters, and psychological factors in the outcome of whiplash associated disorders. J.Neurol.Neurosurg.Psychiatry 2004;75:758-64.

12. Holm L, Cassidy JD, Sjogren Y et al. Impairment and work disability due to whiplash injury following traffic collisions. An analysis of insurance material from the Swedish Road Traffic Injury Commission. Scand.J.Public Health 1999;27:116-23.


14. Adams H, Ellis T, Stanish WD et al. Psychosocial factors related to return to work following rehabilitation of whiplash injuries. J.Occup.Rehabil. 2007;17:305-15.

15. Buitenhuis J, Jaspers JP, Fidler V. Can kinesiophobia predict the duration of neck symptoms in acute whiplash? Clin.J.Pain 2006;22:272-7.

16. Buitenhuis J, Spanjer J, Fidler V. Recovery from acute whiplash: the role of coping styles. Spine 2003;28:896-901.

17. Buitenhuis J, de Jong PJ, Jaspers JP et al. Relationship between posttraumatic stress disorder symptoms and the course of whiplash complaints. J.Psychosom.Res. 2006;61:681-9.

18. Swartzman LC, Teasell RW, Shapiro AP et al. The effect of litigation status on adjustment to whiplash injury. Spine 1996;21:53-8.

19. Gun RT, Osti OL, O’Riordan A et al. Risk factors for prolonged disability after whiplash injury: a prospective study. Spine 2005;30:386-91.

43

Recovery from acute whiplash: the role of coping styles

J. Buitenhuis, J. Spanjer, V. Fidler

Published in: Spine 2003;28(9): 896–901

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Abstract

Study design: Prospective cohort study. Victims of car accidents who initiated compensation claim procedures at a Dutch insurance company and presented themselves with neck complaints were sent a questionnaire containing neck-related questions and questions regarding the coping styles used shortly after the accident. An additional two questionnaires were administered 6 and 12 months, respectively, after the accident.

Objectives: To examine the association between the coping styles used and the development of late whiplash syndrome.

Summary of background data: Previous research has indicated that neither personality traits nor psychopathological symptoms can predict the outcome of whiplash. No studies have yet been conducted on the association between coping styles and the development of late whiplash syndrome.

Methods: The coping styles were determined using the Utrecht Coping List. The duration of neck complaints was measured from the time of the accident and from the time of filling in the first questionnaire. Survival analysis was used to study the association between the duration of neck complaints and the explanatory variables.

Results: Of the 363 eligible claimants, 278 (77%) responded to the questionnaire; 242 (67%) were included in the analysis. After 12 months, 40% of the male and 50% of the female participating claimants still had neck complaints. The duration of the neck complaints was associated with gender, palliative reaction, and the seeking social support coping style.

Conclusions: The coping style during the first few weeks after the accident and the gender are related to the duration of neck complaints. (Cox regression: palliative handling relative risk=0.91, p = 0.002, seeking social support relative risk=1.06, p = 0.042 and gender relative risk=1.50, p = 0.036). Thereafter the intensity of somatic complaints plays a role. Paying attention to the coping style could contribute to the prevention of the development of late whiplash syndrome.

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Introduction

Neck complaints are very common in the general population of western countries and are known to have many different causes.1,2,3 Neck pain after an acceleration-deceleration movement of the head, often called whiplash, is increasingly reported in the Netherlands.4 Although the term whiplash is widely used, it is not so much a diagnosis as a description of a process of injury. The acute trauma may be categorized as a sprain of the neck. For many years, victims of car accidents have reported long-lasting complaints of the neck without evidence or structural or somatic trauma. This chronic syndrome with neck, and often with cognitive complaints also, is usually referred to as late whiplash syndrome. In up to 40% of cases, complaints persist one year after the accident.5 During the last decade, late whiplash syndrome has become one of the major reasons for compensation claims after traffic accidents in the Netherlands.

Two factors illustrate that somatic factors alone cannot explain the development of late whiplash syndrome. First, there are major differences between western countries regarding the prevalence and prognosis of late whiplash syndrome.6-11 Second, very low accident velocities, with accelerations usually experienced in daily life, can result in severe, long-lasting, and invalidating complaints.12 Although cervical zygapophysial joints have been reported to be a common source of late whiplash syndrome, recent studies appear not to have addressed this issue properly, and they may perhaps have little to do with whiplash.7 Increasingly, a consensus is developing that social, cultural and personality factors play a major role in the development of this medical, legal, and social dilemma.3,6,7,12-17

To facilitate prevention and treatment, the role of factors responsible for the development of late whiplash syndrome must be determined. Although some studies have reported that neither personality traits nor psychopathological symptoms can predict the outcome, these studies are known to have design and other methodological deficiencies that preclude them from effectively addressing the issue of psychological factors in a meaningful way.18-20 Furthermore, coping styles were, to our knowledge, never subject of specific research; nevertheless seem very relevant.3,21

After an accident the victim has to cope with a stressful, potentially life-threatening event, in addition to the early physical complaints that result from the accident. The victim may also experience and have to cope with the knowledge-dependent fear that the complaints may lead to a chronic and invalidating disease.6,9 An active coping style is usually considered preferable in this regard and improving active coping strategies is advised as main treatment goal.22 A prospective study regarding the role of coping styles

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in the recovery from whiplash has not yet been published. In this paper, we present the results of a study of the coping styles used as a risk factor for the development of late whiplash syndrome.

Methods

Between March and November 1999, all victims of car accidents who had initiated compensation claim procedures at a Dutch insurance company and presented themselves with neck complaints were invited to participate in the study. Claimants younger than 18 or older than 65 years of age, victims with structural injuries, loss of consciousness or with a history of chronic pain were excluded.

In the Netherlands, the settlement of personal injury claims is based on liability insurance in which the accident victims seek compensation from the insurer of the driver at fault. The invitation letter made it clear that the study was independent of the compensation procedure. The claimants were sent a questionnaire concerning the accident and their complaints at that moment. Table 1 provides an overview of the items on the questionnaire. The claimants were also asked to fill in the Utrecht Coping List (UCL).23

The UCL is a Dutch questionnaire used for measuring general coping styles. It explicitly asks people to fill in the 47 questions concerning how they deal with problematic situations in general. Its validity and reliability have been tested for several Dutch populations.23

The UCL measures coping as a personality characteristic. It consists of the following seven subscales: active handling, palliative reaction, avoidance, seeking social support, passive reaction pattern, expression of emotions and reassuring thoughts. Both 6 and 12 months after the accident, the course of the complaints was monitored by means of additional questionnaires.

Methods of survival analysis (Kaplan-Meier method, log-rank test, Cox regression) were used to investigate the association between the duration of the neck complaints measured from the date of the accident and the explanatory variables. The explanatory variables were age, gender, coping styles and the answers to the questionnaire. In Cox regression, the effect of explanatory variables on time-to-an-event is described by means of hazard ratio, or relative risk. A relative risk <1 signifies a longer time-to-event.

A separate analysis was carried out of only those claimants who still had complaints at the time of completion of the UCL. The time that had elapsed between the accident and the date that the first questionnaire was returned, the ”delay time”, was included in the

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analysis as a potential explanatory variable. To investigate the effect of nonresponse (and for this purpose only), we used the log-rank test to compare the time-to-claim-closure of responders and nonresponders. Time-to-claim-closure is the time between the accident and the moment the claim compensation procedure ends, and is used as an outcome in automobile insurance studies.24 Statistical tests were performed at the 5% significance level.

Results

The invitation and first questionnaire were sent to 614 claimants, in 72% of cases within 30 days of the accident; 341 (55%) addressees responded to the questionnaire. Of the 614 addressees, 251 turned out not to fulfill the entry criteria (16 pre-existent neck complaints, 48 no neck complaints/no car accident, 158 no damage claimed/no trauma known, 10 too old/too young, 19 accompanying trauma and various). Of the 363 eligible claimants, 278 (77%) responded to the questionnaire. Eighty-five did not return the questionnaire or indicated that they did not want to participate. Because 36 returned an incomplete questionnaire, 242 (67%) were included in the analysis.

Table 1. Overview of variables analyzed in relationship to the duration of neck complaints.

Variable range

Utrecht Coping list, subscales: active handling (7 items) 7 to 28 palliative reaction (8 items) 8 to 32 avoidance (8 items) 8 to 32 seeking social support (6 items) 6 to 24 passive reaction pattern (7 items) 7 to 28 expression of emotions (3 items) 3 to 12 reassuring thoughts (5 items) 5 to 20 Neck pain intensity 1 (no pain) – 10 (severe pain) Headache intensity 1 (no pain) – 10 (severe pain) Neck stiffness 1 (no stiffness) – 10 (severe stiffness) Severity of restricted neck movements 1 (no restrictions) –10 (severe restrictions) Extent of neck pain 1 (no) – 10 (severe extent) Severity of paresthesia in the arms 1 (no) – 10 (severe paresthesia) Concentration complaints 1 (no) to 10 (severe complaints) Dizziness 1 (no) to 10 (severe dizziness) Use of medication since accident no/yes Sleep disturbance no/yes Daily duration of pain 1 (always) to 5 (less than 3 hours) Hours after accident until onset of neck complaints (hours) Age (years) Gender (male:female)

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In the total group of 363 eligible claimants, the median time-to-claim-closure was 429 days. The age and sex profiles of responders, partial responders and nonresponders were not significantly different. The median time-to-claim-closure in the study group (362 days) was lower than for the nonresponders (> 2 years). These differences were significant by the log-rank test (p<0.001). Figure 1 presents the Kaplan-Meier curves.

The study group of 242 claimants consisted of 100 (41%) men and 142 women. The average age was 37.3 years (SD 11.2) for men and 34.6 (SD 12.3) for women, and the age range was 18- 62 years. The median time to dispatching the questionnaire to the claimant was 20 days (P25=15, P75=32), the median time to its return (measured from the date of the accident) was 35 days (P25=25, P75=47, range 14-129 days).

Table 2 summarizes the UCL data and presents the results of the Cox regression analysis. After stepwise elimination of the nonsignificant variables, only gender, palliative reaction and the seeking social support coping style remained in the model, with expression of emotions of borderline significance (P value of Wald and log-rank-tests: 0.052 and 0.048). In the final model, the relative risk of these selected variables was nearly identical to that of the full model of Table 2. Figure 2 presents the Kaplan-Meier curves for men and women.

Figure 1. Kaplan-Meier curve of the time-to-claim-closure in a) the non-responders group (the upper curve, n=85), b) the study group (n=242) and c) the group with incomplete data (the lower curve, n=36).

time-to-closure (days)

8006004002000

Perc

enta

ge o

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1.0

.8

.6

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From this analysis we conclude that male gender, a higher score for seeking social support and a lower score for the palliative reaction coping style result in a shorter duration of neck complaints.

Table 2. Cox model regression for relationship between duration of neck pain and all considered explanatory variables in the study group (n=242).

Variable median (range) RR P value 95 % CI

gender (male:female) 1.50 .036 1.03 - 2.21age 34 (18-62) 1.01 .431 0.99 - 1.02active handling 18 (8-26) 1.01 .646 0.95 - 1.08palliative handling 17 (9-29) 0.91 .002 0.85 - 0.97avoidance 15 (9-26) 1.02 .573 0.96 - 1.08seeking social support 13 (6-24) 1.06 .042 1.00 - 1.12passive reaction pattern 10 (7-24) 0.99 .706 0.92 - 1.06expression of emotions 6 (3-11) 0.90 .072 0.80 - 1.01reassuring thoughts 12 (6-20) 1.02 .594 0.94 - 1.12

duration of neck complaints (days)

4003002001000

frac

tion

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Figure 2. Kaplan-Meier curve of the duration of neck complaints in females (upper curve) and males (lower curve).

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Of the 242 claimants, 174 reported neck complaints at the time of the first questionnaire. However, 19 claimants stated in the second questionnaire that the neck complaints had ceased before receiving the first questionnaire and were therefore not included in further analysis. For the remaining group of 155 claimants, we investigated the effect of the information available in the questionnaire on the time-to-claim-closure and on the remaining duration of neck complaints as measured from the date that the first questionnaire was returned.

For 9 of the 155 claimants (6%), no follow-up information on the duration of neck complaints apart from that in the first questionnaire was available. Consequently, the duration of neck complaints was further analyzed for 146 claimants, 51 (35%) men and 95 women, with an average age of 35 years (SD 11.5 years).

Results of Cox regression analysis with stepwise backward elimination of variables are summarized in Table 3. This model shows that the duration of neck complaints is related to the daily duration of pain, paresthesia in the arms, the onset time of the neck pain after the accident, and delay time. After replacing the latter two variables by “headache” and “extent of neck pain,” these two variables were also significant, although the model fitted slightly less well. This behavior is explained by (significant Spearman) correlation between onset time, paresthesia in arms, extent of neck pain, and headache. Figures 3 presents Kaplan-Meier curves for daily duration of pain.

We conclude that a delayed onset of neck pain, more extensive somatic complaints as described by a longer daily duration of pain, more severe paresthesia in the arms, neck pain and headache, and a delayed response to the first questionnaire are associated with a longer duration of neck complaints.

Table 3. Best-fitting Cox model relating neck pain duration to explanatory variables in the group with complaints at first questionnaire *

Variablemedian (range)

RR P-value 95 % CI

delay (days)

35 (14-99) 0.97 .022 0.95 - 1.00

daily duration of pain (1=always to 5=less than 3 hours)

2 (1-5) 1.46 .001 1.17 - 1.82

onset of neck pain after the accident (hours)

1 (0-50) 0.95 .047 0.90 - 1.00

Paraesthesia in arms (1=no to 10=severe)

1 (1-10) 0.64 .008 0.45 - 0.89

* n=145 (1 missing daily duration of pain)

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No effect for the other variables, in particular the coping styles, was found in this group.

Discussion

After analysis of the whole study group, the palliative reaction and seeking social support coping styles were found to be significantly associated with the duration of neck complaints. Furthermore, neck complaints lasted longer in women than in men, which is in accordance with other studies.2,5,25

Analysis of the group still with neck complaints at the time of the first questionnaire revealed no asssociation with a coping style. This group consists of claimants with at least 2 weeks of neck complaints. In this group the severity of the somatic complaints was found to be significantly associated with the duration of neck complaints. Neck pain intensity and age, which were found to predict the outcome of whiplash in other studies, were not found to be correlated with the duration of the neck complaints in this group.14,20,25

These results indicate that the coping style in the first few weeks after the accident plays a role in the development of late whiplash syndrome. After this period, the intensity of somatic complaints seems to determine the duration of neck complaints.

duration of neck complaints (days from Q1)

4003002001000

fract

ion

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nec

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Figure 3. Kaplan-Meier curves of duration of neck complaints by daily duration of pain: always (highest curve), not always but > 6 hours (middle curve) and < 6 hours (lowest curve).

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The association found with the palliative reaction coping style indicates that claimants who, when confronted with a problematic situation, seek distraction, avoid thinking about their problem and try to feel better by smoking, drinking or relaxing, have a longer duration of neck complaints.23

The negative association between duration of neck complaints and scores on the seeking social support coping scale reveals that victims who, when confronted with a problematic situation, seek social comfort and understanding and share their concerns with others, have a shorter duration of neck complaints. A higher score on this coping scale correlates with an internal locus of control that means that outcomes are thought to be under the control of one’s own behavior. 21,23

The borderline significant association with the score on the expression of emotions scale indicates that victims showing annoyance or anger are associated with a longer duration of neck complaints. Both the palliative reaction and the expression of emotions coping styles correlate positively with neuroticism and feelings of fear and inadequacy. 23

These findings indicate that, during the first weeks of neck complaints after a car accident, claimants who seek palliative relief of their complaints, experience fear, annoyance, anger or feel inadequate but do not share their concerns or fear with others are at risk of developing late whiplash syndrome. The daily duration of pain and paresthesia in the arms seem to be indicators for the consolidation or further development of late whiplash syndrome after this period.

In contrast with what could be expected, the active handling coping style was not associated with the duration of neck complaints. However, because a nonpalliative coping strategy will induce more active behavior, this could explain the positive effect of active interventions described in the literature. 22,26-28

The importance of the seeking social support and expression of emotions coping styles are new findings. It indicates that the early emotional aspects of the whiplash injury play an important role in the development of late whiplash syndrome and should be addressed in the initial treatment.3

Previous research showed personality factors not to be able to explain the course of recovery from acute whiplash. 18,20 In this study we found coping styles to be related to the duration of neck complaints. Apart from methodolog aspects the distinct feature of our study concerns the studied psychologic factors. Coping, which can be described as the way a person deals with a stressful event, is determined not only by personality factors but also by earlier experiences and the specific nature of the encountered event and particularly the way it is perceived.

Although the initial invited group consisted of subjects who had initiated

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compensation claim procedures, we do not think that this induced a bias toward more serious complaints. 3,29-31 In the Netherlands, starting such a procedure has a very low threshold. The damage report form, used for claiming the car damage, is usually filled in within a few days of the accident and contains a section to fill in the names of casualties and their complaints. We invited all claimants directly from these forms, including victims who did not seek medical help at that time or did not visit an emergency room at all.

Furthermore, although the insurer and victim can be seen as opposite parties, in the Netherlands most claims, even large ones in which serious injuries are involved, are settled out of court. None of the participating subjects were in actual litigation.

The proportion of claimants with neck complaints 12 months after the accident, 40% for males and 50% for females, is at the high end of the prognosis range found in the literature.5 The nonresponders group appears to have consisted of subjects with even longer lasting complaints, as may be deduced from the longer timeclaimclosure. This could indicate that the same factors that prevented the victims from participating in the study also prolonged the claim procedure.

As in other studies, we should not forget the fact that when people are asked about physical complaints that could also be considered mainly physiologic, there is ample room for misattribution, and hence overreporting of accident-caused complaints.6 Our results contrast with research from some other European countries and indicate that late whiplash syndrome is a major problem in the Netherlands.8-11

Although the coping questionnaire measures coping as a personality characteristic, this does not mean that the coping style measured is static. Rather, it reveals which coping style a person would tend to use in the case of a stressful event. It can therefore be argued that the fact that the neck complaints in some of the victims had ceased by the time the UCL was filled out may have influenced the score on some of the coping scales measured.

The results of this study indicate that the coping style plays a role during the first few weeks of the development of late whiplash syndrome. The results are in accordance with the idea that nonpalliative treatment and an “act as usual” attitude help to prevent chronic complaints. 26,28 We do not think that our results are in contrast with the often used treatment strategy of initial analgesia. 26 In the first days after the acute trauma, adequate medication and proper information can help the patient in continuing their normal activities as much as possible, thereby facilitating favorable behavior. After a few days, this medication should be usually stopped because chronic medication can support the somatization process.

Attention to the early emotional aspects and the coping style used during the initial

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treatment of neck complaints after a car accident could contribute to the prevention of the development of late whiplash syndrome.

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References

1 Bovim G, Schrader H, Sand T. Neck pain in the general population. Spine 1994;19:1307-9

2 Donk J van der, Schouten JSAG, Passchier J, et al. The associations of neck pain with radiological abnormalities of the cervical spine and personality traits in a general population. J Rheumatol 1991;18:1884-9

3 Drottning M, Staff PH, Levin L, et al. Acute emotional response to common whiplash predicts subsequent pain complaints. A prospective study of 107 subjects sustaining whiplash injury. Nordic Journal of Psychiatry 1995;49:293-9

4 Versteegen GJ, Kingma J, Meijler WJ, et al. Neck Sprain in patients injured in car accidents. A retrospective study covering the period 1970-1994. Eur Spine J 1998;7(3):195-200

5 Mayou R, Bryant B. Outcome of whiplash neck injury. Injury 1996;27:617-23

6 Ferrari R. The Whiplash encyclopedia. The facts and myths of whiplash, Gaithersberg, MD: Aspen Publishers, 1999

7 Ferrari R, The many facets of whiplash. Spine 2001;26:2063-4

8 Giebel GD, Bonk A, Edelmann M, et al. Whiplash injury. [letter] J Rheumatol 1999;26:1207-8

9 Obelieniene D, Schrader H, Bovim G, et al. Pain after whiplash: a prospective controlled inception cohort study. J Neurol Neurosurg Psychiatry 1999;66:279-83

10 Partheni M, Constantoyannis C, Ferrari R, et al. A prospective cohort study of the outcome of acute whiplash injury in Greece. Clin Exp Rheumatol 2000;18:67-70

11 Schrader H, Obelieniene D, Bovim G, et al. Natural evolution of late whiplash syndrome outside the medicolegal context. Lancet 1996;347:1207-11

12 Allen ME, Weir-Jones L, Eng P, et al. Acceleration Perturbations of Daily Living. A comparison to ‘Whiplash’. Spine 1994;19(11):1285-90

13 Berry H, Chronic whiplash syndrome as a functional disorder. Arch Neurol 2000;57(4):592-4

14 Cassidy JD, Carroll LJ, Cote P, et al. Effect of eliminating compensation for pain and suffering on the outcome of insurance claims for whiplash injury. N Engl J Med 2000;342(16):1179-86

15 Livingston M. Whiplash injury and peer copying J R Soc Med 1993;86(9):535-6

16 Mechanic D. Social psychological factors affecting the presentation of bodily complaints. N Engl J Med 1972;286(21):1132-9

17 Pearce, JMS. Scientific Review - The myth of chronic whiplash syndrome. Spinal Cord 1999;37(11):741-8

18 Borchgrevink GE, Stiles TC, Borchgrevink PC, et al. Personality profile among symptomatic and recovered patiënts with neck sprain injury, measured my MCMI-I acutely and 6 months after car accidents. J Psychosom Res 1997;42(4):357-67

19 Kwan O, Friel J. Whiplash injury. (letter) J Rheumatol 1999;26:1205-6

20 Radanov BP, Stefano G di, Schnidrig A, et al. Role of psychosocial stress in recovery from common whiplash. Lancet 1991;338:712-5

21 Jensen M, Tuner J, Romano J, et al. Coping with chronic pain: a critical review of literature. Pain 1991;47(3):249-83

22 Scholten-Peeters GGM, Bekkering GE, Verhagen AP, et al. Clinical practice guideline for the physiotherapy of patients with whiplash-associated disorders. Spine 2002;27:412-22

23 Schreurs PJG, Willige G van de, Brosschot JF, et al. De Utrechtse Coping Lijst: UCL. Omgaan met problemen en gebeurtenissen. Herziene handleiding 1993. Swets test Publishers

24 Côté P, Hogg-Johnson S, Cassidy JD, et al. The association between neck pain intensity, physical

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functioning, depressive symptomatology and time-to-claim-closure after whiplash. J Clin Epidemiol 2001;54(3):275-86

25 Harder S, Veilleux M, Suissa S. The effect of socio-demographic and crash related factors on the prognosis of Whiplash. J Clin Epidemio 1998:51(5);377-84

26 Borchgrevink GE, Kaasa A, McDonagh D, et al. Acute treatment of whiplash neck sprain injuries. A randomized trial of treatment during the first 14 days after a car accident. Spine 1998;23(1):25-31

27 Peeters GG, Verhagen AP, Bie RA de, et al. The efficacy of conservative treatment in patients with whiplash injury: a systematic review of clinical trails. Spine 2001;26:E64-73

28 Rosenfeld M, Gunnarsson R, Borenstein P, Early intervention in whiplash-associated disorders. Spine 2000;25:1782-7

29 Mendelson G. Compensation neurosis revisited: outcome studies of the effects of litigation. J Psychosom Res 1995;39(6):695-706

30 Solomon P, Tunks E. The role of litigation in predicting disability outcomes in chronic pain patients. Clin J Pain 1991;7(4):300-4

31 Swartzman LC, Teasull RW, Shapiro AP, et al. The effect of litigation Status on adjustment to whiplash injury. Spine 1996;21(1):53-8

57

Can kinesiophobia predict the duration of neck symptoms in acute whiplash?

J. Buitenhuis, J. Jaspers, V. Fidler

Published in: The Clinical Journal of Pain 2006;22(3):272-77

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Abstract

Objectives: In low back pain, clinical studies suggest that kinesiophobia (fear of movement/(re)injury) is important in the etiology of chronic symptoms. In this prospective cohort study, the predictive role of kinesiophobia in the development of late whiplash syndrome is examined.

Methods: Victims of car collisions with neck symptoms who initiated compensation claim procedures with a Dutch insurance company were sent a questionnaire containing symptom-related questions and the Tampa Scale of Kinesiophobia (TSK-DV). Follow-up questionnaires were administered, respectively 6 and 12 months after the collision. Survival analysis was used to study the relationship between the duration of neck symptoms and explanatory variables.

Results: Of the 889 dispatched questionnaires, 590 (66%) were returned and 367 used for analysis. The estimated percentage of subjects with neck symptoms persisting one year after the collision was 47% (SE 2.7%). In a regression model without symptom-related variables, kinesiophobia was found to be related to a longer duration of neck symptoms (P=0.001). However, when symptom-related information was entered into the model, the effect of kinesiophobia did not reach statistical significance (P=0.089).

Discussion: Although a higher score on the TSK-DV was found to be associated with a longer duration of neck symptoms, information on early kinesiophobia was not found to improve the ability to predict the duration of neck symptoms after motor vehicle collisions.

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Introduction

Few medical subjects give rise to as much discussion and controversy as whiplash.1-5 Although the term ´whiplash´ is widely used, it is not so much a diagnosis as a description of an injury process. The chronic syndrome, with long-lasting symptoms and without evidence of structural or somatic trauma, is often referred to as late or post-whiplash syndrome.

In the last decades, many studies on chronic neck symptoms after motor vehicle collisions have been published in search of discriminating etiological factors.6,7 Studies on somatic theories and mechanical aspects of the trauma are still being published, but recently more articles have focused on psychological, cultural and social factors as an explanation for the various characteristics of this syndrome.1,5,8-13

Although still subject to debate, a general consensus is building that post-whiplash syndrome should be regarded as a functional somatic syndrome with etiological factors known to be involved in similar syndromes.1,14,15

A recent systematic review of prognostic factors stated that high initial pain intensity, restricted cervical range of motion, high number of symptoms, previous psychological problems, and nervousness are considered risk factors for delayed recovery, although the available evidence is not very strong.16 Therefore additional research on possible etiological and predicting variables, including behavioral and cognitive aspects, is needed.

One such potential factor is kinesiophobia. Kinesiophobia is a specific pain-related fear in which a patient has an excessive, irrational, and debilitating fear of physical movement and activity resulting from a feeling of vulnerability to painful injury or reinjury.17 Fear of movement leads to inactivity and is a good predictor for disability in the case of chronic low back pain.18 Pain-related fear plays a central role in the fear-avoidance model. This model offers a framework for conceptualizing the process of developing chronic low back pain.19

In low back pain, clinical studies suggest that an excessively negative orientation toward pain “catastrophizing” and fear of movement/(re)injury are important in the etiology of chronic symptoms.20 In the fear-avoidance model, catastrophizing leads to pain-related fear, leading to avoidance behavior including avoidance of movement and physical activity.19 In low back pain, fear-avoidance beliefs are identified as risk factors for chronic low back symptoms, suggesting these factors are causal.20

Furthermore, chronic low back pain patients who retrospectively reported a sudden traumatic pain onset exhibited higher kinesiophobia than patients who reported that the pain symptoms started gradually.18

Since, in the case of whiplash, it is known that an early active treatment is preferable,

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a passive attitude induced by fear of movement can also play a role in the development of post-whiplash syndrome.21 22,23 For treatment it is of course of great importance to know if fear is the main factor leading to inactivity.

Therefore, because of the apparent role of kinesiophobia in the transition from acute to chronic low back pain, it is conceivable that it could play a role in recovery from acute neck pain as well.

Recent research in this context appears to support this idea.24,25 Nederhand et al. recently concluded that a test for fear of movement can be used to help predict the outcome of traumatic neck pain.25

In this 1-year prospective study we investigate the predictive value of early kinesiophobia on the duration of neck symptoms after motor vehicle collisions.

Materials and Methods

ParticipantsOver a 10-month period, we invited all car collision victims with neck symptoms

who had initiated compensation claim procedures with a Dutch insurance company to participate in the study. We excluded claimants younger than 18 or older than 65 years of age, and victims with structural injuries, loss of consciousness or with a history of chronic pain.

In the Netherlands, the settlement of personal injury claims is based on liability insurance, where accident victims seek compensation from the insurer of the driver at fault. The letter of invitation made it clear that the study was independent of the compensation procedure.

QuestionnairesWe sent the claimants a questionnaire (Q1) concerning the collision and their

symptoms at that time. Table 1 provides an overview of the items on the questionnaire. We also asked the claimants to fill in the Tampa Scale of kinesiophobia (TSK).17

The TSK is a 17-item 4-point questionnaire that measures the fear of (re)injury due to movement. The Dutch version of the TSK (TSK-DV) has good reliability and validity.18,26,27

Six (Q2) and twelve (Q3) months after the collision, we monitored the course of the symptoms by means of two identical questionnaires, which contained a subset of questions of the first questionnaire (Q1). When the neck symptoms had ceased the victims were asked how long the neck symptoms had lasted. From this data the duration of neck symptoms was calculated.

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Statistical analysisWe used Cox model regression to study the relationship between duration of

neck symptoms and explanatory variables.28 We analyzed both the total duration of symptoms starting from the collision and the duration of symptoms after filling out the first questionnaire (Q1). The former analysis involved all eligible subjects and explanatory variables known at the time of the collision, the latter analysis included only subjects with symptoms at the time of filling out Q1. In this analysis we examined the role of the TSK-DV score and of the symptom-related information, while correcting for possible confounding variables. The delay in filling out Q1 (the time between the collision and Q1) and the period in which the accident took place were also included in the analysis.

Note that in Cox regression analysis the effect of an explanatory variable on the duration of symptoms is expressed as a hazard ratio (HR). A HR less than 1 corresponds to a situation where a higher value for the explanatory variable results in a longer duration, a HR above 1 corresponds to a shorter duration. HR is one when there is no relation.

To investigate the effect of non-response, we compared the time-to-claim closure of respondents and partial respondents. Time-to-claim closure is the time between the collision and the moment the claim compensation procedure ends, and is used

Table 1Overview of variables analyzed in relation to the duration of neck symptoms.

Variable values

Age yearsGender male, femaleHead restraints no/yesCollision anticipated no/yesSeat in car during collision 5 possible seatsSite of collision 8 sectorsSeatbelt use no/yesNeck pain intensity 1 (no pain) – 10 (severe pain)Headache intensity 1 (no pain) – 10 (severe pain)Neck stiffness 1 (no stiffness) – 10 (severe stiffness)Severity of restriction of neck movements 1 (no restrictions) –10 (severe restrictions)Radiating pain in arms 1 (no) – 10 (severe pain)Severity of paresthesia in the arms 1 (no) – 10 (severe paresthesia)Concentration symptoms 1 (no) to 10 (severe symptoms)Difficulty reading 1 (no) to 10 (severe symptoms)Difficulty attending to a conversation 1 (no) to 10 (severe symptoms)Dizziness 1 (no) to 10 (severe dizziness)Use of medication since collision no/yesSleep disturbance no/yesDaily duration of pain 1 (always) to 5 (less than 3 hours)Onset of neck symptoms hours after collisionTampa Scale of Kinesiophobia 17 - 68

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in automobile insurance studies.29 We used 5% as the nominal level of statistical significance.

The TSK-DV score and the initial symptoms (questionnaire 1) were recorded at the same time. To answer the question whether the TSK-DV score can be predicted from these symptoms, we carried out multiple linear regression with gender, age and symptom variables as the independent variables.

Computations were carried out using the statistical package SPSS 11.

Results

Participants and responseDuring the intake period we dispatched 889 questionnaires. The median time

of dispatch was 19 days after the collision (P25=13 days, P75=28 days). The number of questionnaires returned was 590 (66%). Among those returned, the median time for return was 32 days after the collision (P10=18 days, P90=65 days). Forty-seven per cent of questionnaires were returned within 30 days, 67% within 40 days. Most collisions took place on Fridays (19%); 12% and 10% of the collisions took place on Saturdays and Sundays.

We studied the total duration of symptoms in a group of 367 eligible subjects. Table 2 summarizes the reasons for exclusion of 223 of the 590 questionnaires received. Compared to the group with insufficient information (n=88), the eligible group (n=367) was on average 3 years younger (t-test, p=0.044), had a similar gender composition (chi-square test, p=0.78) and a similar time-to-claim closure distribution (Cox regression, p=0.74).

Table 2. Overview of included and excluded subjects

Questionnaires sent 889 100% returned 590 66%

excluded Too young/too old 20 No collision/no neck symptoms 101 Insufficient data 88 Already suffered chronic pain or Whiplash 11 Various 3 _______________________________________ Total excluded 223

Eligible 367

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Table 3. Basic characteristics of the eligible group (n=367 unless stated otherwise) and of the study group with symptoms on the first questionnaire (n=211).

Eligible group Study group with symptoms on the first questionnaire

Age Mean (SD) 36 (12) 38 (12)Gender Male (%) 156 (42%) 88 (42%)Car seat Driver 285 (78%) (n=365) 160 (76%)where was the car hit Rear center 269 (81%) (n=332) 156 (74%)Use of seatbelts Yes 340 (93%) 196 (93%)Head restraints Yes 354 (97%) 200 (95%)Collision anticipated Yes 112 (31%) (n=365) 68 (32%)Day of the week Sunday to Saturday 10,11,15,16 ,17,19,12 (%) 10,11,11,18,20,21,10 (%)Delay (collision to Q1, days) median (P25,P75) 31 (22, 43)

Total duration of complaints (days)

4003002001000

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Figure 1. Kaplan-Meier curve of duration of neck symptoms in eligible group (n=367). Vertical strokes mark censored observations.

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Table 3 presents the basic characteristics of the eligible group. During the follow-up, 51% of this group became free of neck symptoms. Figure 1 shows the Kaplan-Meier curve. The estimated percentage of subjects with neck symptoms persisting one year after the collision was 47% (SE 2.7%). The median of the duration of symptoms was 180 days.

In the eligible group (n=367), the first questionnaire was returned after a median delay of 32 days after the collision (P10=18 days, P90=67 days). Of the eligible group, 211 subjects could be included for further analyses of duration of neck symptoms after filling out the first questionnaire. From the respondents we excluded 86 subjects who were already symptom-free, 44 who were symptom-free at the time of filling out the first questionnaire according to the second questionnaire but not according to the first questionnaire (thus providing inconsistent information), and 26 subjects who did not

Table 4. Symptom-related characteristics at first questionnaire (n=211).

Intensity of neck pain (n=210) mean (sd) 6.0 (2.1)Daily duration of pain (n=208) mean (sd) 2.3 (1.4)Hours after collision until onset of neck symptoms, hours (n=209) median (P25,P75) 0 (0, 3)Headache intensity (n=211) mean (sd) 5.0 (2.7)Neck stiffness (n=211): mean (sd) 6.2 (2.6)Severity of restriction of neck movements (n=211) mean (sd) 5.0 (2.3)Extent of neck pain (n=209) mean (sd) 3.5 (2.8)Severity of paresthesia in the arms (n=210) mean (sd) 3.0 (2.7)Use of medication since collision (n=211) yes 120 (60%)Concentration symptoms (n=211) mean (sd) 4.5 (2.9)Difficulty reading (n=211) mean (sd) 4.0 (2.8)Dizziness (n=210) mean (sd) 3.8 (2.9)Sleep disturbance (n=211) yes 116 (55%)Tampa Scale of kinesiophobia score (n=211): mean (sd) 40.5 (8.6) median (P25,P75) 41 (34, 47)

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return the second questionnaire. Table 3 summarizes the basic characteristics of the study group, and Table 4 presents the symptom-related information.

Duration of neck symptomsTable 5 summarizes the results of Cox regression analyses. Three models are presented.

All of them include gender, age, delay, and a variable indicating whether the collision

Table 5 .Results of Cox regression

model 1 model 2 model 3 Variable HR P-value 95%-CI HR P-value 95%-CI HR P-value 95%-CI

Gender (M:F) 1.77 0.034 1.04 - 3.02 1.37 0.25 0.80 - 2.33 1.48 0.151 0.86 - 2.55 Age (10 years) 0.78 0.025 0.63 - 0.97 0.87 0.20 0.69 - 1.08 0.86 0.180 0.68 - 1.07 Study period 0.28 0.038 0.09 - 0.93 0.31 0.054 0.09 - 1.02 0.30 0.046 0.09 - 0.98 Delay (days) 0.98 0.025 0.96 - 1.00 0.98 0.029 0.96 - 1.00 0.98 0.030 0.86 - 1.00 Head restraints (N:Y) 3.06 0.021 1.18 - 7.9 TSK-DV (10 points) 0.47 0.001 0.33 - 0.65 0.73 0.089 0.50 - 1.05 Restricted movements 0.83 0.007 0.73 - 0.95 0.85 0.020 0.74 - 0.98 Radiating pain in arms 0.80 0.003 0.69 - 0.93 0.82 0.010 0.71 - 0.95 Sleep disturbance 2.27 0.007 1.25 - 4.1 2.06 0.019 1.12 - 3.76

HR = Hazard Ratio, CI = Confidence Interval, Study period: first 3 months of the study compared to the rest

occurred during the first three months of the study. These potential ‘basic’ confounders appeared to be related to the outcome at some stage of the analyses, although not all of them are significant in the final models.

Model 1 results from including all variables except the questions concerning the nature of the symptoms. In addition to the basic variables, the model includes the TSK-DV score and the presence of head restraints. According to this model, a score 10 points higher on the TSK-DV corresponds to reducing by about a factor of 2 the instantaneous probability of becoming symptom free. The presence of head restraints was found to be associated with a longer (!) duration of neck symptoms. Kaplan-Meier curves in Figure 2 illustrate the effect of the TSK-DV.

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Model 2 results from considering all variables except the TSK-DV score. We found three variables describing symptoms to be related to the outcome. Neck stiffness, radiating pain in arms, and difficulty falling asleep were associated with longer duration of neck symptoms. Model 3 results from considering all variables together. The results are similar to those in Models 1 and 2; however, the effect of the TSK-DV score is smaller and no longer significant.

The models presented include three questions describing symptoms from the first questionnaire. Because the symptom-related questions are correlated, on interchanging some of these variables with other symptom-related questions we obtained similar results The overall picture is that when we enter symptom-related information into the model, the effect of the TSK-DV score does not reach statistical significance.

In the linear regression analysis the TSK-DV score was found to decrease with age (p=0.054), to be higher for males (p=0.032) and to increase with neck pain, concentration problems and sleep disturbance (all P<0.001); the adjusted r-square was 0.38. Cronbach’s

Duration of complaints after Q1 (days)

4003002001000

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1.0

.8

.6

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(1)

(2)(3)(4)

Figure 2. Kaplan-Meier curve of duration of symptoms in four groups (n=211) defined by quartiles of the TSK-DV score. The position of the curves correspond to the quartiles, the lowest curve being that for subjects with a TSK-DV below P25. Vertical slashes show censored observations.

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alpha for the TSK score was 0.76 (n=211), similar to the value reported for other populations.26

Discussion

Our study shows that a relation exists between the score on the TSK-DV and the duration of neck symptoms. However, when subjective symptom variables are added to the model, the TSK-DV score is no longer significantly related to the duration of neck symptoms. This loss of significance is due to correlation between specific symptoms and the TSK-DV score.

The relation found between the duration of neck symptoms and gender and age has also been reported in other studies.30,31

In accordance with earlier research on kinesiophobia in low back pain, which showed a modest but significant relation between pain intensity and the TSK-DV score, we found the TSK-DV scores to be significantly related to the intensity of neck pain.20,26 This is consistent with the understanding that a relation exists between anxiety and pain.19 Furthermore, we found that men score significantly higher on the TSK-DV, which is also reported in other studies.26 Studies on post-whiplash syndrome, on the other hand, found that whiplash-injury related neck symptoms last longer in women.20,30,32,33 We also found concentration problems and difficulties in falling asleep to be significantly related to the TSK-DV score. This suggests that an interaction exists between kinesiophobia, or pain-related fear, and the frequently reported cognitive symptoms.19

Our results do not seem to be consistent with the study by Nederhand et al.25 There are several items that should be considered when comparing the results.

First, there is a major difference in the targeted population. In the study by Nederhand et al., the participating patients were recruited after visiting a hospital emergency room. From as yet unpublished data in a study using a different sample from the same population, we estimate that only 50% of our targeted population visited a hospital after the collision. Recruiting from patients that visited a hospital after the collision could select a group exhibiting more symptoms and more fear.

Second, the primary outcome variable used is very different. Nederhand et al. used the score on the Neck Disability Index (NDI) after 6 months as primary outcome variable. In our study the duration of neck symptoms is the primary outcome variable.

When the results of the study by Nederhand at al. are considered carefully, the differences are perhaps smaller than at first appear. We could not reject the nulhypothesis of no effect of TSK adjusted for confounders. However, as Nederhand et al. based their

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conclusions on an unadjusted analysis, adjustment of the results could remove the TSK effect in their data as well.

Because the TSK-DV score, when corrected for early subjective symptom reports, does not significantly relate to the duration of neck symptoms, it does not seem suitable as an instrument for predicting the duration of neck symptoms after motor vehicle collisions. However, the fact that the TSK-DV score is significantly related to the duration of neck symptoms when the early subjective symptom information is not considered leaves room for further discussion. Studies on chronic pain have shown that pain-related fear can lead to overprediction of pain, pain vigilance and concomitant muscular activity, and therefore to possible higher scores on pain-related questions.8,19,34-36

We cannot explain the negative effects of head restraints on the duration of neck symptoms, as shown in model 1. Although some studies describe no significant relation between head restraints and the outcome of whiplash, the obvious surmise is that head restraints help to prevent acute neck distortion.37,38 We feel that the negative relation found is an indication of the very limited value of mechanical factors on the development of post-whiplash syndrome.39

We would like to emphasize that this is one of the first studies using the Tampa Scale of Kinesiophobia for patients with neck pain. Furthermore, our study focuses on the duration of neck symptoms, and not disability or other more behavioral parameters. Other studies on the value of kinesiophobia in whiplash used the Neck Disability Index (NDI), and although limited to a six-month follow-up, found no relation between the NDI and the TSK.24,25 To achieve an adequate response we did not include a specific neck pain disability questionnaire.40 Although the validity of some of these questionnaires has recently been questioned, we feel that conclusions on the validity of the fear-avoidance model in neck pain after motor vehicle collisions should be considered carefully. 41

A further limitation of our study is the fact that since it is a mail-out survey there was no control of the conditions under which questionnaires were completed.

Though the study group consisted of subjects who had initiated compensation claim procedures, we do not think that this induced a bias towards more serious symptoms.15,42 In the Netherlands, starting such a procedure has a very low threshold. The damage report form used for claiming the car damage, and usually filled out within a few days of the collision, contains a section for the names of victims and their symptoms. We invited all claimants directly from these forms, including victims who did not seek medical help at the time, or did not visit an emergency room at all. Furthermore, although the insurer

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and victim can be seen as opposing parties, most claims in the Netherlands, even large ones where serious injuries are involved, are settled out of court. None of the participating subjects were in actual litigation.

Although a recent study, using a Functional Capacity Evaluation (FCE) as primary outcome, has found no relation between kinesiophobia and the results on the FCE, future research on the role of kinesiophobia in neck pain after motor vehicle collision should use a disability outcome.43 Since the Tampa Scale of Kinesiophobia was constructed for back pain, it should perhaps be adjusted when used for neck pain. Future research should examine which fears are specific to patients with traumatic neck pain. Furthermore, research on pain catastrophizing and its relation with neck pain after motor vehicle collisions should be conducted.

To sum up, a higher score on the Tampa Scale of Kinesiophobia was found to be associated with a longer duration of neck symptoms, but this relationship ceased to be significant after correction for early subjective symptoms. With knowledge of early symptoms at hand, the information on early kinesiophobia does not improve our ability to predict the duration of neck symptoms after motor vehicle collisions.

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References

1. Berry H. Chronic whiplash syndrome as a functional disorder. Arch Neurol 2000;57:592-4.

2. Cassidy JD, Carroll LJ, Cote P et al. Effect of eliminating compensation for pain and suffering on the outcome of insurance claims for whiplash injury. N Engl J Med 2000;342:1179-86.

3. Ferrari R. Whiplash cultures. CMAJ 1999;161:368.

4. Ferrari R, Kessels RP. Whiplash controversy. Neuropsychiatry Neuropsychol Behav Neurol 2002;15:220-4.

5. Pearce JM. The myth of chronic whiplash syndrome. Spinal Cord 1999;37:741-8.

6. Ferrari R. Whiplash--review of a commonly misunderstood injury. Am J Med 2002;112:162-3.

7. Lovell ME, Galasko CS. Whiplash disorders--a review. Injury 2002;33:97-101.

8. Koelbaek JM, Graven-Nielsen T, Schou OA et al. Generalised muscular hyperalgesia in chronic whiplash syndrome. Pain 1999;83:229-34.

9. Allen ME, Weir-Jones I, Motiuk DR et al. Acceleration perturbations of daily living. A comparison to ‘whiplash’. Spine 1994;19:1285-90.

10. Borchgrevink GE, Stiles TC, Borchgrevink PC et al. Personality profile among symptomatic and recovered patients with neck sprain injury, measured by MCMI-I acutely and 6 months after car accidents. J Psychosom Res 1997;42:357-67.

11. Ferrari R. The whiplash encyclopedia. The facts and myths of whiplash. Gaithersburg: Aspen Publishers, Inc., 1999.

12. Radanov BP, Di Stefano G, Schnidrig A et al. Role of psychosocial stress in recovery from common whiplash [see comment]. Lancet 1991;338:712-5.

13. Malleson A. Whiplash and other useful illnesses. Montreal: McGill-Queen’s University Press, 2002.

14. Barsky AJ, Borus JF. Functional somatic syndromes. Ann Intern Med 1999;130:910-21.

15. Drottning M, Staff PH, Levin L et al. Acute emotional response to common whiplash predicts subsequent pain complaints. Nord J Psychiatry 1995;49:293-9.


17. Kori SH, Miller RP, Todd DD. Kinisophobia: A new view of chronic pain behavior. Pain Manage 1990;3:35-43.

18. Crombez G, Vlaeyen JW, Heuts PH et al. Pain-related fear is more disabling than pain itself: evidence on the role of pain-related fear in chronic back pain disability. Pain 1999;80:329-39.


20. Picavet HS, Vlaeyen JW, Schouten JS. Pain catastrophizing and kinesiophobia: predictors of chronic low back pain. Am J Epidemiol 2002;156:1028-34.

21. Borchgrevink GE, Kaasa A, McDonagh D et al. Acute treatment of whiplash neck sprain injuries. A randomized trial of treatment during the first 14 days after a car accident. Spine 1998;23:25-31.

22. Rosenfeld M, Gunnarsson R, Borenstein P. Early intervention in whiplash-associated disorders: a comparison of two treatment protocols. Spine 2000;25:1782-7.

23. Scholten-Peeters GG, Bekkering GE, Verhagen AP et al. Clinical practice guideline for the physiotherapy of patients with whiplash-associated disorders. Spine 2002;27:412-22.

24. Sterling M, Kenardy J, Jull G et al. The development of psychological changes following

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whiplash injury. Pain 2003;106:481-9.

25. Nederhand MJ, IJzerman MJ, Hermens HJ et al. Predictive value of fear avoidance in developing chronic neck pain disability: consequences for clinical decision making. Arch Phys Med Rehabil 2004;85:496-501.

26. Vlaeyen JW, Kole-Snijders AM, Boeren RG et al. Fear of movement/(re)injury in chronic low back pain and its relation to behavioral performance. Pain 1995;62:363-72.

27. Goubert L, Crombez G, Damme Sv et al. Confirmatory Factor Analysis of the Tampa Scale for Kinesiophobia: Invariant two-factor model across low back pain patients and fibromyalgia patients. Clin J Pain 2004;20:103-10.

28. Kalbfleish JD, Prentice RL. The statistical analysis of failure data. New York: Wiley, 1980.

29. Cote P, Hogg-Johnson S, Cassidy JD et al. The association between neck pain intensity, physical functioning, depressive symptomatology and time-to-claim-closure after whiplash. J Clin Epidemiol 2001;54:275-86.


31. Suissa S, Harder S, Veilleux M. The relation between initial symptoms and signs and the prognosis of whiplash. Eur Spine J 2001;10:44-9.

32. Harder S, Veilleux M, Suissa S. The effect of socio-demographic and crash-related factors on the prognosis of whiplash. J Clin Epidemiol 1998;51:377-84.


34. Arntz A, van Eck M, Heijmans M. Predictions of dental pain: the fear of any expected evil, is worse than the evil itself. Behav Res Ther 1990;28:29-41.

35. Crombez G, Eccleston C, Baeyens F et al. Attention to chronic pain is dependent upon pain-related fear. J Psychosom Res 1999;47:403-10.

36. Ferrari R. Whiplash and symptom amplification. Pain 2001;89:293-5.

37. Minton R, Murray P, Stephenson W et al. Whiplash injury--are current head restraints doing their job? Accid Anal Prev 2000;32:177-85.

38. Morris F. Do head-restraints protect the neck from whiplash injuries? Arch Emerg Med 1989;6:17-21.

39. Ferrari R. Putting head restraints to rest. Accid Anal Prev 2001;33:685-6.

40. Pietrobon R, Coeytaux RR, Carey TS et al. Standard Scales for Measuring of Functional Outcome for Cervical Pain of Dysfunction. Spine 2003;27:515-22.

41. Hoving JL, O’Leary EF, Niere KR et al. Validity of the neck disability index, Northwick Park neck pain questionnaire, and problem elicitation technique for measuring disability associated with whiplash-associated disorders. Pain 2003;102:273-81.


43. Reneman MF, Jorritsman W, Dijkstra SJ et al. Relationship between kinesiophobia and performance in a functional capacity evaluation. J Occup Rehabil 2003;13:277-85.

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Relationship between post-traumatic stress disorder symptoms and the course of whiplash complaints

J. Buitenhuis, P.J. de Jong, J.P.C. Jaspers J.W. Groothoff

Published in: Journal of Psychosomatic Research 2006; 61:681– 689

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Abstract

Objective: This study investigates the relationship between post-traumatic stress disorder symptoms (avoidance, re-experiencing, and hyperarousal) and the presence, severity, and duration of neck complaints after motor vehicle accidents.

Methods: Individuals who had been involved in traffic accidents and had initiated compensation claim procedures with a Dutch insurance company were sent questionnaires (Q1) containing complaint-related questions and the Self-Rating Scale for post-traumatic stress disorder (SRS-PTSD). Of the 997 questionnaires that were dispatched, 617 (62%) were returned. Only car accident victims were included in this study (n=240). Complaints were monitored using additional questionnaires that were administered six (Q2) and twelve months (Q3) after the accident.

Results: Post-traumatic stress disorder was related to the presence and severity of concurrent post-whiplash syndrome. More specifically, the intensity of hyperarousal symptoms that were related to post-traumatic stress disorder at Q1 was found to have predictive validity for the persistence and severity of post-whiplash syndrome at six and twelve months follow-up.

Conclusion: Results are consistent with the idea that post-traumatic stress disorder hyperarousal symptoms have a detrimental influence on the recovery and severity of whiplash complaints following car accidents.

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Introduction

Whiplash is one of the most prevalent post-traumatic diagnoses following traffic accidents. The term whiplash refers to the presumed movement of the neck during an accident. The distortion of the neck that can follow from such movement usually declines over subsequent days or weeks. Even in the absence of identifiable structural injuries, victims may suffer from long-lasting complaints that are characterized by persistent neck pain, often accompanied by cognitive complaints. This persistent syndrome is usually known as whiplash associated disorder (WAD) or post-whiplash syndrome. Studies on the etiology of this chronic syndrome have led to conflicting opinions regarding the nature of the complaints, and the relevance of psychological factors.1-3

Although the majority of victims show spontaneous recovery within the first months after the traffic accident, as many as forty percent of the victims suffer from long-lasting symptoms, sometimes with severely disabling effects.4 Insight into factors that are responsible for this chronic course is therefore of great importance. The determination of such predictive factors may provide clues for effective interventions, in addition to its utility in the context of prevention.Several prognostic factors have already been identified by earlier research.5

First, it has been found that high initial pain intensity, female gender, and increasing age are predictive of delayed recovery.3,4,6 In addition, studies have shown that individual coping style may be involved in the course of whiplash complaints. More specifically, a palliative coping style has proven predictive of a chronic course.3,6

The presence of post-traumatic stress symptoms is another factor that may play an important role in the persistence of whiplash symptoms following a motor vehicle accident.7

Post-whiplash syndrome and post-traumatic stress disorder (PTSD) are both relatively common conditions following traffic accidents.8-11 As many as twenty-three percent of traffic accident victims are reported to have developed PTSD, which is known to have high psychiatric and medical co-morbidity.12-15

The symptoms of PTSD may be involved in the development of post whiplash-syndrome in several ways.

First, anxiety is an important feature of most PTSD symptoms. Because anxiety is known to influence the perception and experience of pain, PTSD symptoms may alter the perception and experience of acute neck pain.16 Inflated pain levels may subsequently fuel (avoidance) behaviors that facilitate a chronic course.17-19

Second, PTSD symptoms may result in heightened vigilance, which may inflate the

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perception of pain.20

Third, PTSD symptoms may give rise to a dysfunctional (catastrophic) interpretation of acute neck pain, which may subsequently inflate pain intensity, disability, and psychological distress, independent of the level of the actual physical impairment.21

Finally, PTSD shares several symptoms with acute whiplash syndrome, including insomnia, irritability, and cognitive problems. These symptoms may further intensify the perception of symptoms or lead to misattribution.

In support of the idea that the presence of PTSD symptoms affects the symptomatology of whiplash, earlier research has provided preliminary evidence to indicate that the acute post-traumatic stress response (i.e., re-experiencing and avoidance symptoms) are related to the intensity of whiplash symptoms four weeks after the accident.22

In addition, the results of a recent study have provided further evidence that PTSD symptoms may also influence the course of whiplash symptoms. More specifically, the study revealed the re-experiencing and avoidance subscales of the Impact of Events Scale to be associated with relatively persistent whiplash complaints at six months follow-up.23,24

Unfortunately, both previous studies tested only two of the three PTSD symptom scales and neither included the hyperarousal symptom cluster scale. Nonetheless, these symptoms may be highly relevant to the proper understanding of the relationship between PTSD and whiplash complaints.7

A study by Mayou and Bryant did consider all three post-traumatic stress disorder symptoms scales. The participants that they recruited, however, included only victims who had visited an emergency room following their accidents, thereby possibly biasing the results toward patients who were more frightened or whose injuries were more serious.25

The present study was therefore designed to provide further testing of the robustness and validity of these earlier findings, which suggest that PTSD symptoms are related to the intensity of whiplash complaints and that they have predictive validity regarding recovery from whiplash complaints following motor vehicle accidents. This study includes the hyperarousal symptom cluster in addition to re-experiencing and avoidance symptoms

To test for generalizability, we did not restrict the range of victims to emergency-room visitors. Finally, we examined whether the relationship between PTSD symptoms and whiplash complaints had increased or decreased at prolonged (twelve-month) follow-up.

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More specifically, the present study addresses the following questions:

1. Are PTSD symptoms more frequent among individuals who have post-whiplash syndrome?

2. Are PTSD symptoms related to the severity of whiplash complaints?3. Is the presence of PTSD symptoms predictive of delayed recovery from post-whiplash

syndrome?

Methods

Study designWe used a prospective longitudinal design. Participants were assessed at one (Q1),

six (Q2), and twelve months (Q3) after their accidents.

Participants and procedureTraffic-accident victims who had initiated compensation claim procedures for

personal injury with a Dutch insurance company were asked to participate in this study. In the Netherlands, settlement of personal injury claims is based on liability insurance; accident victims seek compensation from the insurance company of the driver who was at fault. The letter of invitation clearly communicated that the present study was independent of the compensation procedure.

During the intake period, 997 questionnaires were dispatched. Questionnaires were not sent to claimants who were known to be younger than 18 or older than 65 years of age. The median time for dispatching the questionnaire was 21 days after the accident (mean 22.15 days, SD=11.197). The number of initial questionnaires that was returned was 617 (62%).

The initial selection from the returned questionnaires included only the responses of victims who had been in car accidents (n=293). To rule out the potentially confounding influence of concurrent complaints and to obtain a homogeneous sample of participants with only soft-tissue injuries, 30 victims were excluded because of a history of whiplash or neck pain, 15 because of one or more fractures, and 8 because of the absence of physical complaints. In the final sample, therefore, the responses of 240 participants were eligible for further analysis.

Questionnaires and outcome variablesAfter a median time of 21 days after the accident, we sent each claimant a questionnaire

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(Q1) concerning the accident, the injuries that they had sustained, and their complaints at that time. Table 1 provides an overview of the questionnaire items.

Table 1. Overview of variables analyzed

Variable values

Age yearsGender male, femaleLoss of consciousness no, for a moment, <1 minute, <10 and >10 minutesHospital visit no; immediately by ambulance; immediately, on own initiative; later, after visit to GPHospital admittance no, < 1 day, >1 dayGeneral practitioner visit no, <1 day, <1 week, >1 weekBack-pain intensity 1 (no pain) – 10 (severe pain)Neck-pain intensity* 1 (no pain) – 10 (severe pain)Headache intensity* 1 (no pain) – 10 (severe pain)Neck stiffness* 1 (no stiffness) – 10 (severe stiffness)Severity of neck-movement restriction* 1 (no restrictions) –10 (severe restriction)Radiating pain in arms* 1 (no) – 10 (severe pain)Severity of paresthesia in the arms* 1 (no) – 10 (severe paresthesia)Concentration complaints* 1 (no) to 10 (severe complaints)Difficulty reading* 1 (no) to 10 (severe complaints)Difficulty concentrating on a conversation* 1 (no) to 10 (severe complaints)Dizziness* 1 (no) to 10 (severe dizziness)Use of medication since accident no/yes (includes analgesics and/or muscle relaxants)Sleep disturbance no/yesFrequency of neck pain* Ŧ 1 (daily) to 4 (at least once a month)Onset of neck complaints hours after accidentPost-traumatic stress questionnaire (SRS-PTSD) Three scales

* Variable used in whiplash-severity scoreŦ Before analyses recalculated by using: 12 – (2 x original value))

Consistent with our previous studies on post-whiplash syndrome, claimants who suffered from neck pain, a loss of consciousness of no longer than one minute, and no self-reported previous neck complaints were included as post-whiplash syndrome patients3,6

The presence of post-traumatic stress disorder was assessed using the Self-Rating Scale for PTSD (SRS-PTSD).27 This questionnaire was designed as an abridged version of the Structured Interview for Post-Traumatic Stress Disorder (SI-PTSD), which measures the presence and severity of post-traumatic stress disorder symptoms from both a current and

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a lifetime perspective28. The SRS-PTSD consists of questions that assess the three major symptom groups of post-traumatic stress disorder, as listed in the DSM-IV. Eight questions assess the five re-experiencing symptoms; ten questions assess the seven avoidance symptoms, and six questions assess the five hyperarousal symptoms. In accordance with the DSM-IV criteria for PSTD, participants were considered as suffering from PTSD if they reported at least one re-experience, three avoidance symptoms, and two hyperarousal symptoms.29

We monitored the course of complaints, in all participants, regardless of the presence of initial complaints, at six (Q2) and twelve (Q3) months after the accident by means of the Self-Rating Scale for PTSD (SRS-PTSD). In addition, two identical questionnaires containing questions regarding the complaints at that moment in time were completed.

Data reductionPTSD symptoms

A dichotomous variable was computed for each assessment point to indicate whether the diagnostic requirements for post-traumatic stress disorder were met. In addition to this dichotomous variable, the actual number of avoidance, re-experiencing, and hyperarousal symptoms were used as independent variables.

Whiplash complaintsA severity score was calculated as the sum of the eleven complaint variables that

are marked in Table 1 for each individual who was suffering from post-whiplash syndrome at each of the three assessment points. The reliability of these indices in terms of internal consistency was satisfactory. (Q1: Cronbach’s alpha=0.88, n=134; mean=52.9, sd=20.2, Q2: Cronbach’s alpha=0.89, n=79; mean=53.5, sd=20.5, Q3: Cronbach’s alpha=0.91, n=62; mean=53.0, sd=20.2). In addition, a dichotomous variable was computed for each assessment point to indicate whether whiplash syndrome (i.e., persistent neck pain) was still present.

AnalysisCategorical variables were recoded into appropriate dummy variables before they

were used in the regression analyses. The independent variables used in the regression analyses were first analyzed in associated groups.

When analyzing the relationship between PTSD symptoms and the intensity of concurrent post whiplash-syndrome complaints (section 3.3), the groups consisted of: first group: hospital visit, hospital admission and visit GP. Second group: medication since accident, back-pain complaints and onset of neck complaints. Variables with significant

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properties were then simultaneously included in the final regression analysis, together with age, gender and the categorical PTSD variable or the PTSD symptoms..

When analyzing the relationship between Initial PTSD symptoms and the persistence and severity of post-whiplash syndrome at six and twelve months follow-up (section 3.4), the groups consisted of: first group: hospital visit, hospital admission and visit GP. Second group: back pain intensity, headache intensity, use of medications since accident, concentration, difficulty reading, difficulty concentrating on a conversation and dizziness. Third group: neck-pain intensity, frequency of neck-pain, onset of neck complaints, neck stiffness, severity of neck-movement restriction, radiating pain in arms and severity of paresthesia in the arms. Variables with significant properties were then simultaneously included in the final regression analysis, together with age, gender and the categorical PTSD variable or the PTSD symptoms.

Next, using a backward stepwise selection procedure, the least significant variables were removed (visit GP, headache intensity, back-pain intensity and, when analyzing the PTSD symptoms, dizziness), using the drop-in-deviance test to compare the new with the last model, while retaining age, gender, and the PTSD variable(s) in the model. The final models therefore contain age, gender, the PTSD variable(s), and significant confounders.

Results

General resultsTable 2 provides an overview of the basic characteristics of participants (n=240).

Of the 240 participants in the final sample, 32 (20 with post-whiplash syndrome on Q1) did not return the second questionnaire, and 18 (11 with post-whiplash syndrome on Q1) did not return the third questionnaire. Analysis indicated no significant differences between those who did and those who did not return the questionnaire with respect to their scores during the first assessment.

Table 2 provides an overview of the characteristics of both groups of participants (i.e., those with post-whiplash syndrome and those without) as well as descriptive variables on Q1. Using univariate logistic regression, the group of individuals with post-whiplash syndrome consisted of significantly more women than men. In addition, victims with post-whiplash syndrome had visited their general practitioners relatively frequently. None of the other variables showed significant differences between the groups.

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Table 2. Basic characteristics of the eligible group (n=240) at Q1, one month after the accident.

Post-whiplash syndrome no yes whole group

Number of participants 106 134 240 Age, mean (sd) 35.6 (13.4) 36.3 (12.3) 36.0 (12.8) Gender, male (%) * 48 (45.3) 39 (29.1) 87 (36.3)

Loss of consciousness no (%) 95 (89.6) 120 (89.6) 215 (89.6) for a moment (%) 8 (7.5) 14 (9.5) 22 (9.2) less than 1 minute (%) 0 4 (3.0) 4 (1.7) less than 10 minutes (%) 0 0 0 more than 10 minutes (%) 3 (2.8) 0 3 (1.3)

Hospital visit no (%) 62 (58.5) 70 (52.2) 132 (55.0) immediately, by ambulance (%) 32 (30.2) 38 (28.4) 70 (29.2) immediately, on own initiative(%) 7 (6.6) 13 (9.7) 20 (8.3) later, after a visit to general ) 5 (4.7) 13 (9.7) 18 (7.5) practitioner (%

Hospital admission no (%) 96 (90.6) 123 (91.8) 219 (91.3) yes, 1 day or shorter (%) 7 (6.6) 8 (6.0) 15 (6.3) yes, more than 1 day 3 (2.8) 3 (2.2) 6 (2.5)

Visit to general practitioner ** no (%) 48 (45.3) 20 (14.9) 68 (28.3) yes, the same day (%) 19 (17.9) 27 (20.1) 46 (19.2) yes, within one week (%) 31 (29.2) 71 (53.0) 102 (42.5) yes, after more than one week (%) 8 (7.5) 16 (11.9) 24 (10.0)

Neck-pain intensityŦ - 6.5 (2.25)Neck-pain frequency*** Daily (%) - 116 (86.6) More then 3 hours per week (%) - 8 (6) At least once a week (%) - 9 (6.7) At least once a month (%) - 0 (0%)

*: univariate logistic regression, Odds-ratio=2.016, 95% CI=1.182-3.439)**: univariate logistic regression, reference category “no”, dummy variable (dv) 1: Odds-ratio=3.411 , 95% CI=1.555-7.479, dv 2: Odds-ratio=5.497, 95% CI=2.810-10.752, dv 3: Odds-ratio=4.800, 95% CI=1.773-12.998)***: one missing case Ŧ : Information on other variables available from the first author

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PTSD symptoms at one, six, and twelve monthsThe presence of PTSD and the mean number of symptoms for each symptom cluster

at each assessment point are shown in Table 3.

Table 3. Frequency of post-traumatic stress disorder and symptom scales at one, six and twelve months.

Assessment point Q1 (1) Q2 (6) Q3 (12) (Months after the accident)post-whiplash syndrome no yes no yes no yes

Number of participants 106 134 129 79 128 62

Post-traumatic stress disorder, yes (%) 4 22 4 20 5 11 (3.8) (16.4) (3.1) (25.3) (3.9) (17.7) Re-experiencing symptoms, mean (sd) 1.16 2.11 0.63 1.59 0.67 1.44 (1.442) (1.684) (1.125) (1.581) (1.102) (1.543) Avoidance symptoms, mean (sd) 0.66 1.38 0.50 1.80 0.45 1.77 (1.004) (1.381) (0.772) (1.409) (0.895) (1.311) Hyperarousal symptoms, mean (sd) 0.49 1.66 0.42 1.95 0.37 1.79 (0.928) (1.420) (0.826) (1.440) (0.752) (1.332)

At all assessment points (i.e., Q1, Q2 and Q3), PTSD was more prevalent in the group of victims with post-whiplash syndrome than it was among the participants who did not report these symptoms (Chi-square with Yates’ continuity correction, Χ2=8.53; df=1; p=0.003, Χ2=21.56; df=1; p<0.001 and Χ2=8.65; df=1; p=0.003, respectively).

For all assessments, the mean number of re-experiencing, avoidance, and hyperarousal symptoms was relatively high in the group with post-whiplash syndrome (t-test, t’s<-3.4, p’s<0.001). This pattern remained unaffected when the results were corrected for age and gender using analysis of covariance (F-values>13.73, p’s<0.001).

Of the twenty-six individuals who conformed to the diagnosis of post-traumatic stress disorder at Q1, five (19%) had not visited any doctor after the accident, eleven (42%) had been to a hospital immediately after the accident, and five (19%) had been admitted.

PTSD symptoms and the intensity of concurrent post whiplash-syndrome complaintsUsing the whiplash-severity score at the three assessment points as dependent

variables and all remaining variables from Table 1 as independent variables, linear regression analysis yielded the following results:

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The use of medication (beta=0.289, p<0.001), the severity of back pain (beta=0.275, p<0.001), and the presence of post-traumatic stress disorder at Q1 (beta=0.329, p<0.001) all were associated with the whiplash-severity score at Q1 (independent variables simultaneously included in the analysis: age, gender, back-pain intensity, use of medication, and categorical diagnosis of PTSD at Q1).

In a subsequent regression analysis, we substituted the number of PTSD symptoms for the three symptom clusters for the categorical diagnosis of PTSD (independent variables simultaneously included in the analysis: age, gender, back-pain intensity, use of medication, number of re-experiencing, avoidance, and hyperarousal symptoms). This analysis revealed that the number of post-traumatic avoidance (beta=0.303, p<0.001) and hyperarousal symptoms (beta=0.471, p<0.001) were statistically significantly associated with the concurrent whiplash-severity score at Q1, whereas the number of re-experiencing symptoms at Q1 (beta=-0.091, p=0.191) was not.

The use of medication (beta=0.247, p=0.03), the severity of back pain (beta=0.238, p=0.026), and the presence of post-traumatic stress disorder (beta=0.285, p=0.012) at Q2 were all associated with the concurrent whiplash-severity score.

In a subsequent regression analysis (independent variables simultaneously included in the analysis: age, gender, back-pain intensity, use of medication, number of re-experiencing, avoidance and hyperarousal symptoms), the number of avoidance symptoms (beta=0.308, p=0.028) six months after the accident were associated with the whiplash-severity score at Q2. The number of re-experiencing (beta=0.003, p=0.980) and hyperarousal symptoms (beta=0.242, p=0.088) at six months follow-up provided no statistically significant association with whiplash severity at Q2.

The use of medication (beta=0.267, p=0.031) at Q3 was associated with the concurrent whiplash severity. No statistically significant relationship was found with the presence of post-traumatic stress disorder at that assessment point (beta=0.205, p=0.102).

In a subsequent regression analysis (independent variables simultaneous included in the analysis: age, gender, back-pain intensity, use of medication, number of re-experiencing, avoidance and hyperarousal symptoms), the number of hyperarousal symptoms (beta=0.435, p=0.007) at Q3 were associated with the concurrent whiplash-severity score. The number of re-experiencing (beta=-0.026, p=0.869) and avoidance symptoms (beta=0.167, p=0.238) provided no significant association at Q3.

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Initial PTSD symptoms and the persistence and severity of post-whiplash syndrome at six and twelve months follow-up

Table 4 shows the results of two multiple logistic regression models after stepwise backward modeling, while retaining age, gender and the PTSD variable, using the presence of post-whiplash syndrome at Q2 and Q3 as the dependent variable and the variables from Q1 as independent variables. Most important for the present context, results indicated that the categorical presence of post-traumatic stress disorder at Q1 had no independent predictive value for the presence of post-whiplash syndrome at Q2 and Q3.

Table 4. Multiple Logistic Regression Model. Dependent variable post-whiplash syndrome at Q2 and Q3. Explanatory variables from Q1, including post-traumatic stress disorder.

Variable Coefficient Standard Wald P value Odds 95,0% C.I. (ß) Error Χ2 Ratio Lower Upper Post-whiplash syndrome at Q2

Constant -0.775 1.172 0.437 0.509 0.461 Gender -1.487 0.604 6.056 0.014 0.226 0.069 0.739Age -0.008 0.020 0.175 0.676 0.992 0.955 1.031PTSD 1.440 1.114 1.672 0.196 4.221 0.476 37.450Neck pain 0.353 0.126 7.801 0.005 1.423 1.111 1.822Dizziness 0.283 0.132 4.604 0.032 1.327 1.025 1.718

Post-whiplash syndrome at Q3

Constant -2.526 1.377 3.366 0.067 0.080 Gender -1.126 0.590 3.649 0.056 0.324 0.102 1.030Age 0.010 0.021 0.222 0.638 1.010 0.970 1.052PTSD 1.073 0.864 1.544 0.214 2.924 0.538 15.887Neck pain 0.416 0.141 8.726 0.003 1.516 1.150 1.998Dizziness 0.225 0.109 4.237 0.040 1.253 1.011 1.552

Since the inclusion of neck complaints in the equation may result in an underestimation of the actual strength of the association between PTSD and subsequent complaints (i.e., to the extent that neck pain lies in the causal pathway between PTSD and whiplash complaints), we performed an additional regression analysis in which we did not correct for neck pain at Q1. This additional regression analysis, with only age, gender and the categorical presence of post-traumatic stress disorder at Q1, revealed that the presence of PTSD at Q1 had an independent predictive value for the presence of post-whiplash syndrome at Q2 (Odds-ratio=13.941, 95% CI=1.757-110.600) and Q3 (Odds-ratio=7.518, 95% CI=1.583-35.718).

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In a subsequent analysis, we substituted the number of PTSD symptoms for the three symptoms clusters at Q1 for the categorical diagnosis of PTSD. Table 5 shows the results of the two models. With respect to the PTSD symptoms, only the number of hyperarousal symptoms at Q1 provided additional predictive value for the presence of subsequent post-whiplash syndrome at six and twelve months follow-up.

Table 5. Multiple Logistic Regression Model. Dependent variable post-whiplash syndrome at Q2 and Q3. Explanatory variables from Q1, including post-traumatic stress disorder symptoms.

Variable Coefficient Standard Wald P value Odds 95,0% C.I. (ß) Error Χ2 Ratio Lower Upper


Constant -0.820 1.227 0.447 0.504 0.440Gender -1.572 0.657 5.724 0.017 0.208 0.057 0.753Age -0.004 0.020 0.041 0.840 0.996 0.958 1.035Re-experiencing symptoms -0.268 0.194 1.898 0.168 0.765 0.523 1.120Avoidance symptoms 0.308 0.279 1.213 0.271 1.360 0.787 2.351Hyperarousal symptoms 0.686 0.289 5.633 0.018 1.985 1.127 3.497Neck pain 0.378 0.126 8.993 0.003 1.459 1.140 1.868


Constant -2.836 1.445 3.850 0.050 0.059Gender -1.076 0.619 3.025 0.082 0.341 0.101 1.146Age 0.018 0.021 0.678 0.410 1.018 0.976 1.062Re-experiencing symptoms -0.267 0.191 1.950 0.163 0.766 0.527 1.114Avoidance symptoms -0.012 0.259 0.002 0.963 0.988 0.595 1.641Hyperarousal symptoms 0.810 0.287 7.948 0.005 2.248 1.280 3.947Neck pain 0.438 0.138 10.072 0.002 1.549 1.182 2.031

Linear regression using the whiplash severity score as the dependent variable yielded similar results, showing hyperarousal symptoms at Q1 to be related to the severity of whiplash complaints at six (Q2) and twelve (Q3) months (beta=0.350, p=0.013, and beta=0.325, p=0.045 respectively). No relationship emerged between the number of re-experiencing and avoidance symptoms at Q1 and the whiplash-severity score at either Q2 or Q3.

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Discussion

The major results of the present study can be summarized as follows:Post-traumatic stress disorder and the number of its symptoms are more prevalent i. among car-accident victims who have post-whiplash syndrome than they are among victims who do not.The presence of post-traumatic stress disorder symptoms was associated with relatively ii. more severe concurrent post-whiplash syndrome complaints. Specifically, the initial number of hyperarousal symptoms was found to have predictive iii. validity for the persistence and severity of post-whiplash syndrome at six and twelve months follow-up.

In accordance with earlier research, post-traumatic stress disorder and its symptoms were found to be more prevalent among victims who had post-whiplash syndrome in the first six months following their accidents.22,23

Since earlier research has shown that the development of post-traumatic stress disorder is not substantially related to either the severity of the accident or the severity of the sustained injury, differences in the frequency of PTSD are not readily explained by any apparently terrifying aspect of the accident.30,31 The current results seem to correspond with earlier research that suggests that victims with post-whiplash syndrome generally considered the accident more frightening than did other car accident victims.25 Because perceived threat is of paramount importance in developing post-traumatic stress disorder, it could be speculated that the presence of whiplash complaints is threatening and induces anxiety complaints. This would make the accident more frightening and could subsequently lead to a relatively high number of post-traumatic stress complaints.

Previous research showing a relationship between post-whiplash syndrome and PTSD has relied predominantly on victims who were recruited in emergency rooms, thereby possibly biasing the results toward patients who were more frightened or whose injuries were relatively serious.25 In the present study, only a small minority of the car-accident victims who were included had actually visited a hospital following the accident. The present finding that the relationship between post-whiplash syndrome and PTSD can also be found in a broader sample underlines its generalizibility and indicates that this relationship reflects a robust phenomenon.

The relationship between post-whiplash complaints and PTSD symptomatology was especially pronounced for the PTSD-related hyperarousal symptoms. The mean number of hyperarousal symptoms was three to five times higher among participants with post-whiplash syndrome at all three assessment points. Because the hyperarousal symptom cluster closely resembles anxiety-disorder symptoms, this finding may indicate

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that general anxiety symptoms bear an important influence on the perceived severity of post-whiplash syndrome. The present finding that victims who reported neck complaints visited their general practitioners more frequently than did those who had no neck complaints provides further indication that anxiety is involved. In other words, although a visit to the general practitioner may be interpreted as indicating that the initial symptoms in this group were relatively severe, it may also reflect reassurance-seeking behavior due to relatively high levels of anxiety. One way to test this idea would be to focus on anxiety reduction during initial interventions. If indeed heightened anxiety levels act in a way to inflate whiplash complaints, anxiety reduction should have a beneficial influence on the intensity of whiplash complaints.

In contrast to earlier research, we found no evidence of a relationship between re-experiencing symptoms and post-whiplash syndrome.22,23 One possible explanation could be that we were able to control for hyperarousal symptoms in our analysis. Even after discarding the hyperarousal symptoms, however, we found no significant role for re-experiencing symptoms. The difference may therefore be caused by the present recruitment strategy. It may well be that the relationship between re-experiencing symptoms and post-whiplash syndrome is evident only in victims who have visited an emergency room.

Several earlier studies of post-traumatic stress symptoms have used the Impact of Events Scale.23 While this scale includes the first two major symptom clusters, it does not address hyperarousal symptoms. Our results clearly show that the hyperarousal symptoms have the most marked relationship with post-whiplash syndrome. We therefore recommend that future research on the role of post-traumatic stress disorder in post-whiplash syndrome consider all three symptoms scales. In addition, future research should provide further investigation of the apparent role of hyperarousal symptoms in post-whiplash syndrome.

It should be acknowledged that the present prognostic design does not allow for strong conclusions regarding causal mechanisms that may underlie the co-occurrence of post-whiplash syndrome and PTSD symptoms. Nonetheless, the present pattern of results is clearly consistent with the idea that the concurrent presence of PTSD may have an undesirable influence on the course of whiplash complaints.

One way in which PTSD symptoms may influence the course of whiplash complaints is via the anxiety features of PTSD that may alter the perception and experience of the physical complaints.16

Furthermore, PTSD symptoms may fuel a vulnerability to the misinterpretation

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and catastrophization of the physical sensations that accompany hyperarousal and are associated with pain. These sensations may subsequently be attributed to post-whiplash syndrome or aggravate its symptoms.1,32-34

In addition, anxiety-induced heightened vigilance may inflate the perception of pain.20 Consistent with this idea, the present study has provided evidence that the intensity of PTSD symptoms at Q1 has predictive value for the course of whiplash complaints at follow-up. More specifically, it was found that the presence of a relatively large number of hyperarousal symptoms was related to more intense post-whiplash syndrome complaints at six and twelve months follow-up. These results suggest that general anxiety symptoms are more relevant in this respect than are PTSD symptoms that are more specific (e.g., re-experiencing and avoidance symptoms).

The hyperarousal symptom cluster closely resembles irritability, insomnia, hypervigilance, and similar symptoms. Hypervigilance, which is unique to PTSD, is known to be correlated with higher reported pain intensity, negative affectivity, and catastrophic thinking.35 Accordingly, it may be that symptom amplification and catastrophization may play a role in the consolidation and perceived severity of post-whiplash syndrome, independent of anxiety as such.1 One way to explore this possibility would be to conduct a prospective study to test the predictive value of catastrophic thoughts regarding either the attribution of somatic complaints or the expected course of complaints.

It is important to note that the PTSD hyperarousal scale addresses symptoms regar-ding concentration, memory function, feelings of insecurity, and nervousness. Some of these symptoms are also often attributed to post-whiplash syndrome. It is therefore possible that the predictive properties of the hyperarousal scale are at least partially caused by the fact that this scale measures complaints that are associated with post-whiplash syndrome. The present pattern of results, which indicates that only hyperarousal and none of the other PTSD symptoms are related to the prognosis of post-whiplash syndrome, further substantiates this idea. The present pattern of results is also consistent with the idea that at least some post-whiplash syndrome complaints are, actually symptoms of PTSD. The pattern further highlights the importance of considering PTSD, particularly the hyperarousal features, when diagnosing and treating individuals with apparent post-whiplash syndrome complaints.7

With respect to earlier research, a number of comments are in order regarding the relatively low number of participants who had post-traumatic stress disorder and those who suffered from both post-whiplash syndrome and post-traumatic stress disorder after one month (11% and 16%, respectively).30,36

One explanation might be that research designs that rely on recruiting participants

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from among emergency-room visitors or from referring doctors may overestimate the frequency of post-traumatic stress disorder after motor vehicle accidents, as they may concentrate on a group of victims who are more seriously injured or, more importantly, more frightened than the average victim is. The lower prevalence of post-traumatic stress disorder may therefore have been caused by the fact that we were able to include a considerable number of participants who had not visited an emergency room, or even a medical doctor, following their accidents. The variable findings that are reported in the literature, may thus reflect the nature of samples and methodology, at least in part.37

Additional comments are in order regarding the research sample. The study group consisted of participants who had initiated compensation claim procedures. Since the threshold for starting such procedures is low in the Netherlands, there seems to be no strong reason to suspect that this introduced a bias toward patients whose complaints were more serious.38

First, the damage-report forms that are used for claiming car damage, and which are usually completed within a few days after the accident, contain a section for the names of victims and their complaints. We invited all claimants directly from these forms, including victims who had not visited an emergency room or sought medical help at the time of the accident.

Second, although the insurance company and victims can be seen as opposing parties, most personal injury claims in the Netherlands, even large ones that involve serious injuries, are settled out of court. None of the participants was in actual litigation.

Nevertheless, some studies have recently found that compensation is a critical factor to consider when studying post-whiplash syndrome.39,40

Therefore, the personal injury claimant context should be taken into account when interpreting or generalizing our findings. Furthermore, since the exact nature and expectations of compensation may vary greatly from country to country, we advise caution when extrapolating results of one population onto another.

Finally, it should be acknowledged that post-traumatic stress disorder is not a questionnaire diagnosis. The presence of the minimum number of symptoms required in the three major symptom clusters does not necessarily imply the presence of post-traumatic stress disorder. Structured DSM interviews identify a smaller percentage of victims of post-traumatic stress disorder than do self report questionnaires.27 Questionnaire results, including those that are used here, should therefore be interpreted with caution.

Our results confirm earlier research, which showed that recovery from post-whiplash syndrome after six and twelve months is related to the severity of initial symptoms3-6

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Furthermore, the present results replicated previous findings that indicated that women are over-represented among accident victims with post-whiplash-syndrome.3,6

To conclude, a considerable number of individuals with post-whiplash syndrome were also found to suffer from post-traumatic stress symptoms. More specifically, the number of hyperarousal symptoms at 21 days after the accident was found to be related to the persistence and severity of post-whiplash syndrome symptoms at both six and twelve months follow-up. It is therefore worthwhile to consider symptoms of post-traumatic stress disorder and anxiety in general when evaluating and treating patients with post-whiplash syndrome after motor vehicle accidents.

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References

1. Barsky AJ, Borus JF. Functional somatic syndromes. Ann.Intern.Med. 1999;130:910-21.

2. Berry H. Chronic whiplash syndrome as a functional disorder. Arch.Neurol. 2000;57:592-4.




6. Harder S, Veilleux M, Suissa S. The effect of socio-demographic and crash-related factors on the prognosis of whiplash. J.Clin.Epidemiol. 1998;51:377-84.



9. Mayou R, Bryant B, Duthie R. Psychiatric consequences of road traffic accidents. BMJ 1993;307:647-51.


11. Versteegen GJ, Kingma J, Meijler WJ et al. Neck sprain in patients injured in car accidents: a retrospective study covering the period 1970-1994. Eur.Spine J. 1998;7:195-200.

12. Blanchard EB, Buckley TC, Hickling EJ et al. Posttraumatic stress disorder and comorbid major depression: is the correlation an illusion? J.Anxiety.Disord. 1998;12:21-37.

13. Blanchard EB, Hickling EJ, Freidenberg BM et al. Two studies of psychiatric morbidity among motor vehicle accident survivors 1 year after the crash. Behav.Res.Ther. 2004;42:569-83.

14. Blaszczynski A, Gordon K, Silove D et al. Psychiatric morbidity following motor vehicle accidents: a review of methodological issues. Compr.Psychiatry 1998;39:111-21.


16. Chibnall JT, Duckro PN. Post-traumatic stress disorder in chronic post-traumatic headache patients. Headache 1994;34:357-61.

17. Arntz A, de Jong PJ. Anxiety, Attention and Pain. J.Psychosom.Res. 1993;37:423-32.

18. Arntz A, Dreesen L, de Jong PJ. The influence of anxiety on pain: Attentional and attributional mediators. Pain 1994;56:307-14.


20. Roelofs J, Peters ML, Vlaeyen JW. Selective attention for pain-related information in healthy individuals: the role of pain and fear. Eur.J.Pain 2002;6:331-9.

21. Severeijns R, Vlaeyen JW, van den Hout MA et al. Pain catastrophizing predicts pain intensity, disability, and psychological distress independent of the level of physical impairment. Clin.J.Pain 2001;17:165-72.

22. Drottning M, Staff PH, Levin L et al. Acute emotional response to common whiplash predicts

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subsequent pain complaints. Nord J Psychiatry 1995;49:293-9.

23. Sterling M, Kenardy J, Jull G et al. The development of psychological changes following whiplash injury. Pain 2003;106:481-9.

24. Sundin EC, Horowitz MJ. Horowitz’s Impact of Event Scale evaluation of 20 years of use. Psychosom.Med. 2003;65:870-6.



27. Carlier IVE, Lamberts RD, Uchelen JJv et al. Clinical utility of a brief diagnostic test for posttraumatic stress disorder. Psychosom.Med. 1998;60:42-7.

28. Davidson J, Smith R, Kudler H. Validity and reliability of the DSM-III criteria for posttraumatic stress disorder. Experience with a structured interview. J.Nerv.Ment.Dis. 1989;177:336-41.

29. American Psychiatric Association. Diagnostic and Statistical manual of Mental Disorders, 4th edition. Washington DC: American Psychiatric Association, 1993.

30. Ehlers A, Mayou RA, Bryant B. Psychological predictors of chronic posttraumatic stress disorder after motor vehicle accidents. J.Abnorm.Psychol. 1998;107:508-19.

31. Osti OL, Gun RT, Abraham G et al. Potential risk factors for prolonged recovery following whiplash injury. Eur.Spine J. 2004.

32. Bloom SL. The Complex Web of Causation: Motor Vehicle Accidents, Comorbidity and PTSD. In: Hickling EJ, Blanchard EB, eds. The International Handbook of Road Traffic Accidents & Psychological Trauma. Oxford: Elsevier Science Ltd., 1999:155-84.

33. McFarlane AC, Atchison M, Rafalowicz E et al. Physical symptoms in post-traumatic stress disorder. J.Psychosom.Res. 1994;38:715-26.

34. Sharp TJ, Harvey AG. Chronic pain and posttraumatic stress disorder: mutual maintenance? Clin.Psychol.Rev. 2001;21:857-77.

35. Crombez G, Eccleston C, Broeck Avd et al. Hypervigilance to Pain in Fibromyalgia. The Mediating Role of Pain Intensity and Catastrophic Thinking About Pain. Clin.J.Pain 2004;20:98-102.

36. Blanchard EB, Hickling EJ, Taylor AE et al. Who develops PTSD from motor vehicle accidents? Behav.Res.Ther. 1996;34:1-10.

37. Mayou R. Medical, Social and Legal Consequences. In: Hickling EJ, Blanchard EB, eds. The International Handbook of Road Traffic Accidents & Psychological Trauma. Oxford: Elsevier Science Ltd., 1999:43-56.



40. Joslin CC, Khan SN, Bannister GC. Long-term disability after neck injury. a comparative study. J.Bone Joint Surg.Br. 2004;86:1032-4.

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Catastrophizing and Causal Beliefs in Whiplash

J. Buitenhuis, P.J. de Jong, J.P.C. Jaspers, J.W. Groothoff

Published in: Spine 2008;33(22):2427–33

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Abstract

Study Design, Objective: Prospective cohort study.This study investigates the role of pain catastrophizing and causal beliefs with regard to severity and persistence of neck complaints after motor vehicle accidents.

Summary of Background Data: In previous research on low back pain, somatoform disorders and chronic fatigue syndrome, pain catastrophizing and causal beliefs were found to be related to perceived disability and prognosis. Furthermore, it has been argued with respect to whiplash that culturally dependent symptom expectations are responsible for a chronic course.

Methods: Individuals involved in traffic accidents who initiated compensation claim procedures with a Dutch insurance company were sent questionnaires (Q1) containing the Neck Disability Index (NDI), the Pain Catastrophizing Scale (PCS) and the Causal Beliefs Questionnaire – Whiplash (CBQ-W). Of the 1252 questionnaires dispatched, 747 (59.7%) were returned. Only car occupants with neck complaints were included in this study (n=140). Complaints were monitored using additional questionnaires administered six (Q2) and twelve months (Q3) after the accident.

Results: Pain catastrophizing and causal beliefs were related to the severity of concurrent whiplash disability. The severity of initial complaints was related to the severity and persistence of whiplash complaints. Attributing initial neck complaints to whiplash was found to predict the persistence of disability at six and twelve months follow-up, over and above the severity of the initial complaints. Conclusions: The results suggest that causal beliefs may play a major role in the perceived disability and course of neck complaints after motor vehicle accidents, whereas pain catastrophizing is predominantly related to concurrent disability.The current findings are consistent with the view that an early conviction that neck complaints are caused by the medico-cultural entity whiplash has a detrimental effect on the course of symptoms.

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Introduction

In recent decades, whiplash has become the most common diagnosis following motor vehicle accidents.1 In its acute phase whiplash is defined as myogenic neck complaints after a sprain of the neck.

Although the majority of patients show spontaneous recovery within the first few months after a traffic accident, in as many as forty percent of cases these acute complaints lead to a chronic syndrome with neck pain and often cognitive complaints.2-4 This chronic syndrome is often referred to as late or post-whiplash syndrome, characterized by unexplained physical and cognitive symptoms. Although still subject to debate, a general consensus is building that post-whiplash syndrome should be regarded as a functional somatic syndrome in which cultural as well as psychological factors play a major role.5,6

Post-whiplash syndrome can lead to invalidating effects and long-term work disability7,8. It is therefore of paramount importance to gain insight into the factors responsible for this chronic course.

Earlier work in the context of other chronic disorders characterized by unexplained physical complaints, such as chronic low back pain, provided evidence to suggest that pain catastrophizing and attributional bias are of crucial importance in the development of chronic complaints.9 In the Fear-Avoidance model for chronic musculoskeletal pain, the pathway from pain experience to fear, anxiety and avoidance, leading ultimately to disuse and disability, is modulated by catastrophizing and threatening illness beliefs.10 Similar mechanisms may also apply to chronic neck complaints.4,11,12 Preliminary support for this comes from recent studies showing that fear of pain and the presence of relatively intense anxiety symptoms are related to poor prognosis of neck complaints following motor vehicle accidents.4,13

Pain catastrophizing refers to an exaggeratedly negative orientation towards actual or anticipated pain.14 Earlier research has found that the habitual tendency to make catastrophic interpretations of pain is associated with a heightened pain experience in various patient groups.15 Furthermore, catastrophizing has been associated with heightened disability in chronic pain, independent of the level of actual physical impairment.16-18

The first aim of the present study is to investigate whether pain catastrophizing is similarly involved in the development of chronic neck pain following motor vehicle accidents. In addition, this study investigated the role of ‘causal illness beliefs’.

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Causal illness beliefs can be defined as the patient’s ideas about the origin or cause of the symptoms or illness experienced. It has been found in chronic fatigue syndrome that somatic illness beliefs are associated with increased symptoms and functional impairment, worse subjective and objective outcomes and poor prognosis.19,20 In somatoform disorders organic causal attributions are associated with a need for medical diagnostic examinations, increased expression of complaints and body scanning.21 In addition, inadequate illness beliefs were found to be associated with heart-focused anxiety.22

In a similar vein, dysfunctional causal beliefs may also apply to myogenic neck complaints after motor vehicle accidents. Dysfunctional causal beliefs can be defined as the attribution of the cause of acute myogenic neck complaints to severe, neural or irreparable causes. At the chronic stage, somatic or organic beliefs in general can be considered dysfunctional.

Medical interpretation and explanation of myogenic neck pain after motor vehicle accidents by general practitioners or emergency room staff, commonly held knowledge and culturally defined ideas may give rise to dysfunctional illness beliefs regarding the cause of the neck complaints, which in turn may result in a chronic course.23

Furthermore, dysfunctional causal beliefs are thought to be caused or fuelled by culturally embedded beliefs regarding the course and severity of whiplash. It has been demonstrated that symptom expectations for whiplash differ between countries known to have different prevalence figures for chronic whiplash.24-29 Accordingly, it has been argued that these symptom expectations, and hence the attribution of complaints to whiplash, are responsible for more severe and prolonged complaints.23,27,28

Additionally, it is conceivable that pain catastrophizing leads to more dysfunctional causal beliefs. The tendency to attribute neck complaints to irreparable or severe causes in its turn may elicit catastrophical interpretations of potentially benign myogene symptoms. Catastrophizing and dysfunctional causal beliefs could thus lead to a negative spiral, augmenting symptom severity and discharging into irrational expectations regarding the course of the symptoms and disability, fuelling a chronic course.10,30

In sum, this prospective study examined the predictive validity of catastrophizing

and causal beliefs in the development of post-whiplash syndrome after motor vehicle accidents. More specifically, we tested the following predictions:

1. Pain catastrophizing and causal beliefs – especially the attribution of neck complaints to whiplash – are related to more severe whiplash complaints.

2. Pain catastrophizing and causal beliefs – especially the attribution of neck complaints to whiplash – hamper the recovery from acute whiplash complaints.

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Methods

Study designWe used a prospective longitudinal design. Participants were assessed at one (Q1),

six (Q2) and twelve months (Q3) after their accidents.

Participants and procedureTraffic-accident victims who had initiated compensation claim procedures for

personal injury with a Dutch insurance company were asked to participate in this study. In the Netherlands, the settlement of personal injury claims is based on liability insurance with the accident victims seeking compensation from the insurance company of the driver at fault.

During the intake period, 1252 questionnaires were dispatched. Questionnaires were not sent to victims known to be younger than 18 or older than 65. The number of initial questionnaires returned was 747 (59.7%). Non-response analysis revealed no significant difference in age (t-test, p=0.98) and gender (Chi-square, p=0.20).

The initial selection from the returned questionnaires included only the responses of victims with neck complaints at Q1 who had been involved as drivers or passengers in a car accident (n=156).

To rule out the potentially confounding influence of concurrent complaints and to obtain a homogeneous sample of participants with only soft-tissue injuries, 16 victims were excluded because of a history of whiplash or other chronic pain, one or more fractures, or a loss of consciousness of longer than one minute. In the final sample therefore, 140 participants’ responses were eligible for further analysis.

Questionnaires and outcome variablesAfter a median time of 25 days (mean 26.44 days, SD=9.32) after the accident, we

sent each claimant a questionnaire (Q1) concerning the accident, the injuries they had sustained, and their complaints at that time.

Consistent with our previous studies on post-whiplash syndrome, participants suffering from neck pain, loss of consciousness of no longer than one minute and no self-reported previous neck complaints were included as post-whiplash syndrome patients.3,4,13

Disability was measured using the Neck Disability Index (NDI). The NDI consists of 10 items with a six-point scale, addressing functional activities (personal care, lifting,

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reading, work, driving, sleeping and recreational activities), pain intensity, concentration and headache.31 The NDI has been shown to be valid, reliable, and sensitive to change in a population of patients suffering from neck pain and showed a high internal consistency.31

Pain catastrophizing was measured using the Pain Catastrophizing Scale (PCS).14,32 The PCS is a 13-item self-report measure asking participants to reflect on past painful experiences and to indicate the degree to which they experience thoughts or feelings during pain on a five-point scale, ranging from 0 (not at all) to 4 (always). Previous research showed that the PCS has adequate psychometric properties, with good temporal stability (Pearson’s r2 = 0.92) and adequate internal consistency33.

To assess the participants’ causal beliefs of post-traumatic neck complaints we used the Causal Beliefs Questionnaire Whiplash (CBQ-W), which was developed for this study. This CBQ-W was developed by defining four dimensions of causations, based on clinical experience and known causes of cervical symptoms – a muscle or ligament injury, a vertebral injury, a neural or cerebral injury and psychological factors. Four questions were formulated for each dimension covering different injury severities (see Table 1). Finally, two questions were added (items 4 and 8) to test specific beliefs – i.e. that the cause of symptoms is “whiplash” and something is irreparably damaged – not specifically related to one of the four dimensions.

The questionnaire starts with “My complaints are caused by”, followed by 18 possible causes as listed in Table 1. Participants were asked to indicate on a 4-point scale (absolutely not, probably not, probably yes or absolutely yes) whether the particular origin is likely to be correct.

Furthermore, all patients completed a standardized self-administered questionnaire.

The presence (yes/no) and severity (NDI score) of post-whiplash syndrome at Q1, Q2 and Q3 were defined as general outcome variables.

Causal Beliefs Questionnaire Whiplash (CBQ-W)By means of exploratory factor analysis (principal component analysis with VARIMAX

rotation), the factor structure of the CBQ-W was investigated. On the basis of their eigenvalues and through the inspection of the scree plot, five factors were found (see Table 1).Factor 1 contains items referring to an expected psychological origin of the complaints (CBQ-W Psychological). Factor 2 contains items referring to an expected severe injury as

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the cause of the complaints (CBQ-W Severe Injury). Factor 3 (CBQ-W Vertebral) contains items referring to an expected vertebral origin of the complaints, with the exception of “something broken in my neck” (item 9), which loads on factor 2. Factor 4 (CBQ-W Muscular) contains items regarding the expected muscular origin of the complaints, with the exception of “there is a muscle tear” (item 11) which was included in factor 2 because of its higher factor loading. Due to the unsatisfactory reliability of factor 5, it was not used in the further analysis. Instead item 4 (“My complaints are caused by whiplash”) was included as a possible predictive variable in the analysis (CBQ-W Whiplash) for its specific attributional value.

All in all, the factor structure obtained has face validity and reflected four theoretically meaningful dimensions that came close to our a priori dimensions. We have therefore used the mean value of the obtained factor scales in the subsequent analyses.

Table 1. The Causal Beliefs Questionnaire Whiplash (CBQ-W), with factor loadings after VARIMAX

rotation

Components

1 2 3 4 5

Eigenvalues 4.825 2.353 1.796 1.381 1.151

Reliability (Cronbach’s alpha) .838** .778* .830* .671*** .490*

My complaints are caused by: 5. me being emotionally upset .872 - - - - 18. me being afraid of something .825 - - - - 13. me being shocked by the accident .808 - - - - 7. me being under psychological pressure .692 - - - - 9. something being broken in my neck - .787 - - - 10. damage to my spinal cord - .689 - - - 15. brain injury - .586 - - - 17. my nerves not working properly - .568 - - - 11. a muscle tear - .537 - - - 8. something being irreparably damaged - .446 - - - 12. my vertebrae not lining up - - .856 - - 6. something to do with my vertebrae - - .832 - -

16. my vertebrae being shifted - - .827 - -

3. spraining of my neck muscles or ligaments - - - .770 -

1. something to do with my muscles or ligaments - - - .757 -

14. bruising of my muscles or ligaments - - - .748 -

4. whiplash - - - - .775

2. nerve injury - - - - .732

Only factorloadings >.4 printed.

*: n=137, **: n=138, ***:n=139

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Results

General resultsTable 2 provides an overview of the basic characteristics of the participants at Q1, Q2

and Q3.

Of the 140 participants in the final sample, 18 did not return the second and third questionnaires, and 12 did not return the third questionnaire. Analysis indicated no significant differences with respect to scores during the first assessment between those who did and those who did not return the questionnaires.

Table 2. Overview of the basic characteristics of participants with post-whiplash syndrome at Q1 (1 month), Q2 (6 months) and Q3 (12 months) after the accident.

Q1 Q2 Q3

N 140 122 110Post-whiplash syndrome, number (%) 140 (100) 81 (66.4) 62 (56,4)Gender, female (%) 95 (67.9) 56 (69,1) 43 (69.4)Age, mean (SD) 36.4 (12.0) 35.6 (12.3) 36.9 (12.8)

NDI score, mean (SD) 16.7(8.9) 16.7 (8.3) 17.4 (8.0)Severity of paresthesia, mean (SD) 2.6 (2.4) 3.2 (2.6) 3.1 (2.6)Radiating pain in arms, mean (SD) 3.3 (2.6) 3.3 (2.7) 3.7 (2.8)

PCS Total, mean (SD) 12.94 (11.3) 13.78 (10.97) 13.82 (11.49)

CBQ-W Psychological, mean (SD) 1.69 (0.82) 1.74 (0.80) 1.79 (0.83) Severe Injury, mean (SD) 1.45 (0.40) 1.55 (0.42) 1.57 (0.47) Vertebral, mean (SD) 1.91 (0.74) 2.13 (0.86) 1.94 (0.77) Muscular, mean (SD) 2.97 (0.69) 2.73 (0.82) 2.55 (0.85) Whiplash, mean (SD) 2.45 (0.88) 2.86 (1.07) 2.87 (1.11)

Relationship between the CBQ-W, PCS and Neck Disability ScoresTo explore the relationship between the PCS, the CBQ-W factors and the concurrent

NDI scores, Spearman correlation coefficients were calculated (see Table 3). In line with predictions, the correlational analysis shows that on all three occasions

pain catastrophizing is associated with a higher concurrent NDI score.Similarly, the CBQ-W factors are also correlated with a higher concurrent NDI score

at Q1, Q2 and Q3.To explore the independent contribution of pain catastrophizing and the various

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types of causal beliefs we carried out a multiple linear regression analysis using the NDI Score as the dependent variables at Q1, Q2 and Q3 respectively and the concurrent PCS score, CBQ-W factors, age and gender as predictor variables.

Table 3. Spearman correlations between PCS and CBQ-W factors, and concurrent Neck Disability Index (NDI) scores, at Q1, Q2 and Q3 NDI Q1 Q2 Q3 n = 140 n = 81 n = 62

PCS at Q1 .58**

CBQ-W at Q1 Psychological .39** Severe Injury .41** Vertebral .31** Muscular .32** Whiplash .36**

PCS at Q2 .58**CBQ-W at Q2 Psychological .32** Severe Injury .49** Vertebral .31** Muscular .36** Whiplash .57**

PCS at Q3 .52**CBQ-W at Q3 Psychological .33** Severe Injury .63** Vertebral .43** Muscular .41** Whiplash .53**

*: Correlation is significant at the 0.05 level (2-tailed)**: Correlation is significant at the 0.01 level (2-tailed)

Table 4 shows the results after backward stepwise elimination while retaining age and gender. Pain catastrophizing scores show an independent relationship with the concurrent NDI score on all three occasions.

All CBQ-W factors, with the exception of CBQ-W Severe Injury and CBQ-W Psychological, are independently related to the NDI score at Q1. The CBQ-W Whiplash also contributes independently to the concurrent NDI score at Q2 and Q3. Analysis at Q3 also reveals that CBQ-W Severe Injury is significantly related to the concurrent NDI score.

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Age and gender provide no significant contributions to any of the models.The prognostic value of causal beliefs and pain catastrophizing for the persistence of post-whiplash syndrome

Table 4. Multiple Linear Regression Model. Dependent variable: Neck Disability Index at Q1, Q2 and Q3. Explanatory variables from Q1, Q2 and Q3 respectively.

Variable Coeffi- Stand. 95.0% C.I. Stand. cients Error Lower Upper Coeffi- (ß) cients (B) t p-value

Dependent variable: Neck Disability Index at Q1, independent variables from Q1

Age 0.05 0.05 -0.05 0.14 .06 0.898 0.371Gender 1.37 1.29 -1.19 3.93 .07 1.061 0.291CBQ-W Psychological 1.58 0.93 -0.26 3.43 .15 1.701 0.091 CBQ-W Vertebral 2.33 0.82 0.71 3.95 .19 2.845 0.005CBQ-W Muscular 2.31 0.89 0.55 4.06 .18 2.600 0.010CBQ-W Whiplash 1.92 0.68 0.57 3.27 .19 2.813 0.006PCS 0.29 0.07 0.15 0.42 .37 4.160 <0.001Constant -8.43 3.60 -15.57 -1.30 -2.340 0.021


Age 0.09 0.06 -0.02 0.20 .13 1.633 0.107Gender 0.29 1.48 -2.67 3.24 .02 0.192 0.848CBQ-W Muscular 1.61 0.86 -0.10 3.32 .16 1.872 0.065CBQ-W Whiplash 3.00 0.66 -1.69 4.31 .38 4.558 <0.001PCS 0.34 0.07 0.21 0.47 .45 5.216 <0.001Constant -4.44 3.32 -11.05 2.17 -1.338 0.185


Age 0.05 0.06 -0.06 0.17 .09 0.924 0.359Gender -1.74 1.87 -5.49 2.01 -.10 -0.928 0.358CBQ-W Severe Injury 5.09 2.01 1.06 9.12 .30 2.531 0.014CBQ-W Whiplash 2.39 0.73 0.92 3.86 .33 3.260 0.002PCS 0.19 0.09 0.01 0.36 .26 2.159 0.035Constant -0.85 3.83 -8.53 6.83 -0.223 0.825

After backward stepwise elimination, while retaining age and gender. Model 1 (Q1): R2=.48. Model 2 (Q2): R2=.55. Model 3 (Q3): R2=. 55Variables entered at step 1: age, gender, CBQ-W Psychological, CBQ-W Severe Injury, CBQ-W Verte-bral, CBQ-W Muscular, CBQ-W Whiplash, PCS total score

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Table 5 shows the results of two multiple logistic regression models after stepwise backward modelling, while retaining age and gender, using the persistence of post-whiplash syndrome at Q2 (model 1) and Q3 (model 2) as dependent variables, and the variables from Q1 as predictor variables.

The NDI score at Q1 shows a significant relationship with the persistence of post-whiplash syndrome at Q2 and Q3. Most importantly for the present context, the results indicate that the CBQ-W Psychological and CBQ-W Whiplash factors at Q1 have independent predictive value for the presence of post-whiplash syndrome at Q2 and Q3, over and above the NDI score at Q1.

Table 5. Multiple Logistic Regression Model. Dependent variable post-whiplash syndrome at Q2 and Q3. Explanatory variables from Q1.

Variable Coeffi- Stand. Wald P value Odds 95.0% C.I. cient Error ΧΧ2 Ratio Lower Upper (ß)

Dependent variable: Post-whiplash syndrome at Q2

Age -0.03 0.02 1.53 0.216 0.974 0.933 1.016Gender 0.58 0.57 1.03 0.310 1.792 0.582 5.520Neck Disability Index 0.18 0.05 12.54 <0.001 1.197 1.084 1.323CBQ-W Psychological 1.47 0.52 7.93 0.005 4.335 1.562 12.030CBQ-W Vertebral 1.30 0.47 7.70 0.006 3.686 1.467 9.258CBQ-W Whiplash 1.23 0.38 10.34 0.001 3.430 1.618 7.272PCS -0.12 0.04 8.24 0.004 0.885 0.814 0.962Constant -7.29 1.84 15.61 <0.001 0.001

Dependent variable: Post-whiplash syndrome at Q3

Age 0.01 0.02 0.09 0.765 1.006 0.966 1.048Gender 0.53 0.58 0.83 0.362 1.695 0.544 5.276Neck Disability Index 0.15 0.04 10.86 0.001 1.156 1.061 1.260CBQ-W Psychological 0.98 0.46 4.63 0.031 2.670 1.091 6.534CBQ-W Vertebral 0.84 0.44 3.70 0.055 2.307 0.984 5.411 CBQ-W Whiplash 0.98 0.35 7.64 0.006 2.657 1.329 5.314PCS -0.06 0.04 7.64 0.097 0.942 0.878 1.011Constant -7.19 1.78 16.34 <0.001 0.001

After backward stepwise elimination, while retaining age and gender. Model 1 (Q2): R2=.41 (Cox&Snell), .56 (Nagelkerke). Model ΧΧ2(7) = 61.67. Model 2 (Q3): R2=.39 (Cox&Snell), .52 (Nagelkerke). Model ΧΧ2(7) = 52.02. Variables entered at step 1: age, gender, NDI, paresthesia, radiating pain to the arms, CBQ-W Psychological, CBQ-W Severe Injury, CBQ-W Vertebral, CBQ-W Muscular, CBQ-W Whip-lash, PCS total score

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With regard to the presence of post-whiplash syndrome at Q2, CBQ-W Vertebral also shows a significant contribution, whereas the PCS score was found to be statistically significant, yet with an odds ratio of <1, which indicates a negative contribution. However, univariate logistic regression analysis reveals a small positive relationship between the PCS score at Q1 and the persistence of post-whiplash syndrome at Q2 (odds ratio=1.044, 95% CI=1.001–1.088, p=.042) and Q3 (odds ratio 1.061, 95% CI=1.017–1.108, p=.006).

Discussion

The major results of the present study can be summarized as follows:The severity of neck disability at one, six and twelve months follow-up is associated i. with concurrent pain catastrophizing.The severity of early complaints is related to the persistence of whiplash at six and ii. twelve months follow-up.Attributing initial neck complaints to whiplash was found to be related to more severe iii. concurrent disability and to have prognostic value for the persistence of whiplash at six and twelve months follow-up, over and above the initial complaint severity.

Consistent with research into chronic pain, pain catastrophizing was found to be related to concurrent neck disability.16,18 Because of the correlational design of the present findings it is not possible to determine whether more severe disability leads to more pain catastrophizing or vice versa. However, since early pain catastrophizing was not found to have independent prognostic value for whiplash complaints at twelve months follow-up, the present pattern of findings provides no convincing support for the idea that pain catastrophizing plays an important role in the generation and persistence of whiplash complaints.

In line with previous research, more severe initial complaints were related to the persistence of whiplash at both six and twelve months follow-up.3,4,34

Most importantly for the present context, the results show that attributing neck complaints to whiplash has a predictive value over and above the intensity of initial complaints. Therefore, independent of the severity of initial complaints, attributing the perceived complaints to whiplash seems to have a detrimental influence on the prognosis. Although earlier studies have argued that symptom expectation, obligatory after attributing complaints to the medico-cultural entity “whiplash” could be responsible for the development of chronic whiplash complaints, the present study is the first to actually show a negative prognostic effect of attributing complaints to whiplash.24-26,35

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The finding that attributing early complaints to whiplash is an important factor with regard to concurrent disability and prognosis not only supports theories regarding the potential influence of cultural embedded causal beliefs, but also has important implications for management and treatment. The present findings suggest modifying symptom expectations regarding whiplash and altering the causal attribution of initial myogenic neck complaints as two possible therapeutic strategies.

Altering symptom expectation is a cultural process that should be employed at the population level, typically requiring educational campaigns and professional guidelines.36-38 Although this could lead to a broad and definitive strategy at the population level, it is to be expected that this will be a slow process taking several years. Altering causal beliefs is an individual process that can readily be employed by developing a cognitive behavioural intervention aiming at modifying these specific causal convictions.

The present findings also indicate that attributing initial complaints to psychological factors has additional prognostic value regarding the persistence of disability after one year. This finding is consistent with previous research showing that early anxiety-related distress was related to delayed recovery from post-whiplash syndrome.13 Cognitive behavioural interventions may also be helpful to reduce the influence of this type of dysfunctional convictions.

Finally, it was found that attributing early complaints to vertebral causes is related to persistent complaints at six months and with borderline significance at twelve months follow-up. This seems especially important since physiotherapy and/or manual therapies concentrating on alleged vertebral causes are quite common in acute whiplash39. In light of the fact that, by definition, no vertebral abnormalities are found in common whiplash, our results suggest that a therapy implicitly suggesting a vertebral cause could have adverse effects by fuelling dysfunctional beliefs.

Some comments are in order with respect to this study’s limitations.All findings regarding the CBQ-W should be interpreted with care since the

connotations regarding whiplash are highly culturally dependent. It could well be that this same questionnaire in a different population, especially with different cultural beliefs regarding neck complaints after motor vehicle accidents, would lead to different results.27,28 It would therefore be beneficial to investigate expectations and beliefs regarding whiplash in relation to causal beliefs in different populations.25/26

In addition, the present sample consisted of participants who had initiated compensation claim procedures. However, the threshold for starting such procedures is low in the Netherlands, there seems to be no strong reason to suspect that this

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introduced a bias toward patients whose complaints were more serious.40 Nevertheless, some studies have found that compensation is a critical factor to consider when studying post-whiplash syndrome.41,42 Therefore, the personal injury claimant context should be taken into account when interpreting our findings. Furthermore, since the exact nature and expectations of compensation may vary greatly from country to country, we advise caution when extrapolating results from one population to another.

To conclude, the present results indicate that causal beliefs have important prognostic value for the course of post-whiplash symptoms. Moreover, the pattern of findings supports the view that an early conviction that neck complaints are caused by the medico-cultural entity “whiplash” has a detrimental influence on the course of symptoms and may contribute to delayed recovery.

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References

1. Versteegen GJ, Kingma J, Meijler WJ et al. Neck sprain in patients injured in car accidents: a retrospective study covering the period 1970-1994. Eur.Spine J. 1998;7:195-200.




5. Barsky AJ, Borus JF. Functional somatic syndromes. Ann.Intern.Med. 1999;130:910-21.

6. Berry H. Chronic whiplash syndrome as a functional disorder. Arch.Neurol. 2000;57:592-4.

7. Gozzard C, Bannister G, Langkamer G et al. Factors affecting employment after whiplash injury. J.Bone Joint Surg.Br. 2001;83:506-9.


9. Vlaeyen JW, Kole-Snijders AM, Boeren RG et al. Fear of movement/(re)injury in chronic low back pain and its relation to behavioral performance. Pain 1995;62:363-72.

10. Leeuw M, Goossens ME, Linton SJ et al. The Fear-Avoidance Model of Musculoskeletal Pain: Current State of Scientific Evidence. J.Behav.Med. 2006.

11. Raak R, Wallin M. Thermal thresholds and catastrophizing in individuals with chronic pain after whiplash injury. Biol.Res.Nurs. 2006;8:138-46.

12. Vangronsveld K, Damme SV, Peters M et al. An experimental investigation on attentional interference by threatening fixations of the neck in patients with chronic whiplash syndrome. Pain 2006;127:121-8.

13. Buitenhuis J, de Jong PJ, Jaspers JP et al. Relationship between posttraumatic stress disorder symptoms and the course of whiplash complaints. J.Psychosom.Res. 2006;61:681-9.

14. Sullivan MJ, Pivik J. The Pain Catastrophizing Scale: Development and Validation. Psychol Assess 1995;7:524-32.

15. Sullivan MJ, Thorn B, Haythornthwaite JA et al. Theoretical perspectives on the relation between catastrophizing and pain. Clin.J.Pain 2001;17:52-64.

16. Sullivan MJ, Stanish W, Waite H et al. Catastrophizing, pain, and disability in patients with soft-tissue injuries. Pain 1998;77:253-60.

17. Sullivan MJ, Stanish W, Sullivan ME et al. Differential predictors of pain and disability in patients with whiplash injuries. Pain Res.Manag. 2002;7:68-74.

18. Severeijns R, Vlaeyen JW, van den Hout MA et al. Pain catastrophizing predicts pain intensity, disability, and psychological distress independent of the level of physical impairment. Clin.J.Pain 2001;17:165-72.

19. Vercoulen JH, Swanink CM, Fennis JF et al. Prognosis in chronic fatigue syndrome: a prospective study on the natural course. J.Neurol.Neurosurg.Psychiatry 1996;60:489-94.


21. Rief W, Nanke A, Emmerich J et al. Causal illness attributions in somatoform disorders: associations with comorbidity and illness behavior. J.Psychosom.Res. 2004;57:367-71.

22. Eifert GH, Hodson SE, Tracey DR et al. Heart-focused anxiety, illness beliefs, and behavioral impairment: comparing healthy heart-anxious patients with cardiac and surgical inpatients.

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J.Behav.Med. 1996;19:385-99.

23. Ferrari R. Whiplash cultures. CMAJ. 1999;161:368.

24. Ferrari R, Lang C. A cross-cultural comparison between Canada and Germany of symptom expectation for whiplash injury. J.Spinal Disord.Tech. 2005;18:92-7.


26. Ferrari R, Obelieniene D, Russell A et al. Laypersons’ expectation of the sequelae of whiplash injury. A cross-cultural comparative study between Canada and Lithuania. Med.Sci.Monit. 2002;8:CR728-CR734.

27. Schrader H, Obelieniene D, Bovim G et al. Natural evolution of late whiplash syndrome outside the medicolegal context. Lancet 1996;347:1207-11.

28. Obelieniene D, Schrader H, Bovim G et al. Pain after whiplash: a prospective controlled inception cohort study. J.Neurol.Neurosurg.Psychiatry 1999;66:279-83.

29. Partheni M, Constantoyannis C, Ferrari R et al. A prospective cohort study of the outcome of acute whiplash injury in Greece. Clin.Exp.Rheumatol. 2000;18:67-70.


31. Vernon H, Mior S. The Neck Disability Index: a study of reliability and validity. J.Manipulative Physiol Ther. 1991;14:409-15.

32. van Damme S, Crombez G, Vlaeyen JW et al. De Pain Catastrophizing Scale: Psychometrische karakteristieken en normering. Tijdschrift voor Gedragstherapie 2000;3:209-20.

33. Crombez G, Vlaeyen JW, Heuts PH et al. Pain-related fear is more disabling than pain itself: evidence on the role of pain-related fear in chronic back pain disability. Pain 1999;80:329-39.


35. Ferrari R, Schrader H. The late whiplash syndrome: a biopsychosocial approach. J.Neurol.Neurosurg.Psychiatry 2001;70:722-6.

36. McClune T, Burton AK, Waddell G. Evaluation of an evidence based patient educational booklet for management of whiplash associated disorders. Emerg.Med.J. 2003;20:514-7.

37. Motor Accidents Authority. Guidelines for the Management of Whiplash-Associated Disorders. Sydney, Australia: Motor Accidents Authority, Claims Advisory Service, 2001.

38. Carlsson I. The Whiplash commission final report. Stockholm, Sweden: Whiplashkommissionen, 2005.

39. Scholten-Peeters GG, Bekkering GE, Verhagen AP et al. Clinical practice guideline for the physiotherapy of patients with whiplash-associated disorders. Spine 2002;27:412-22.




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General discussion and conclusions

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Introduction

Research on the consequences and aetiological factors related to neck pain after motor vehicle accidents has proven to be a sensitive subject, often leading to polemical discussions. Nevertheless, considering the consequences of chronic post-traumatic neck pain and the relatively high incidence of long-lasting symptoms in the Netherlands, insight into factors related to the prognosis which provide clues for prevention and treatment are urgently needed.

Thus far there have been only a limited number of studies on whiplash carried out in the Netherlands. Moreover, most of the research involves studies with a relatively small number of participants. Furthermore, since there is evidence indicating that cultural factors play an important role in whiplash, it is very important to conduct research within the Dutch context to investigate whether the results from international studies can be extrapolated to the Dutch situation in a straightforward fashion, or whether specific domestic factors related to the prognoses and treatment of whiplash in the Netherlands need to be explored. Therefore, the first aim of the present studies was to provide insight into whiplash in the Netherlands and to study the relevant factors in the Dutch context.

In the Netherlands, in the last decade there seems to be a remarkable reduction in the number of whiplash cases being seen by first-line physicians, although there are no reliable epidemiological figures. Recently, a Dutch research programme was even halted because of an insufficient number of participants.1 However, this tendency has not been observed in liability claims. Whiplash continues to occur frequently and is responsible for a large part of the costs of liability claims.2 In the present studies participants were recruited on the basis of their liability claims. Recruiting patients through a liability insurer is rather unique, even from an international perspective, but it has nevertheless proved to be an effective way of recruiting a decent-sized group sizes. Recruiting patients on the basis of liability claims not only guarantees a relatively large number of potential participants but also provides the opportunity to investigate whiplash in a claim situation.

The present research represents a first attempt to test a series of particular hypotheses directly. In short, the present series of studies investigated the following issues. The first study investigated the relationship between whiplash and work disability. Second, the role of coping style in the course of neck complaints after motor vehicle accidents was studied. The third study investigated the association between kinesiophobia and recovery from whiplash. Subsequently, the relevance of post-traumatic stress disorder with regard to the prognosis of whiplash was studied. And finally, pain catastrophizing and the influence of causal illness beliefs on the prognosis of whiplash were investigated.

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General discussion

Whiplash and work disabilityWork disability is one of the major financial factors in liability claims relating to whiplash complaints. Furthermore, previous research has shown that sick leave and disability pension costs are much higher than the costs of acute medical care, demonstrating that these parameters are of paramount importance when evaluating the consequences of neck pain after motor vehicle accidents.3,4 However, the previous studies on work disability related to whiplash are very heterogeneous, mainly due to cultural diversity in the conceptualization of work disability and social security systems, and they are often limited in sample size and consequently show wide variability in results.5-14

Therefore, part of the present thesis was designed to investigate work disability in relation to whiplash in the Netherlands. The results presented in Chapter 2 show that work disability due to post-whiplash syndrome after a motor vehicle accident is a common problem. More than half the population with neck complaints which was studied was work-disabled after the accident. Fortunately, the vast majority recovered from their work disability in the first year. Nevertheless, a substantial number of the participants (12.6%) showed persistent work disability after one year.

Detailed analyses revealed that at one month, work disability is independently related to physical factors such as higher neck pain intensity and more restricted neck movements, together with the use of medication and complaints about concentration. At six months, neck pain intensity and complaints about concentration remain related to the concurrent work disability, whereas at one-year follow-up only the intensity of the complaints about concentration were consistent with the concurrent work disability.

With respect to the predictive value of the factors measured the results show that work disability after six months was independently related to higher age and more initial intense concentration and headache complaints. Of all the factors available one month after the accident, work disability after one year was independently related to higher age and more intense concentration complaints.

This pattern was similar for blue and white-collar workers. Although one might expect white-collar workers to be affected more by concentration problems, surprisingly the results show that prolonged work disability is related to concentration complaints independently of the degree of manual labour (blue or white-collar work) or level of concentration. In a similar vein, neither self-employment nor gender proved to be significant predictive factors related to work disability.

Thus it appears that apart from age, concentration problems constitute a general factor that is associated with a poor prognosis in terms of work disability. This does not imply that other factors may not be involved in the persistence of work disability due

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to whiplash complaints (see below). In previous research the intensity of early neck pain was found to be a main factor related to recovery from complaints. However, in relation to work disability this was not the case; early neck pain intensity had no independent predictive value with regard to returning to work. It is generally accepted that cognitive complaints, including reported concentration difficulties, are due to pain interference. It could therefore be expected that a higher level of experienced pain would lead to more reported concentration difficulties. Apparently, concentration difficulties have more implications for work than the reported pain level. One explanation could be that work acts as a distraction from pain. However, when concentration problems make work more difficult, or nearly impossible, work can no longer lead to distraction from physical complaints, thereby possibly contributing to continued work disability.Obviously it should be acknowledged that the present prognostic design does not allow for strong conclusions regarding causal mechanisms. Nonetheless, when it comes to interventions, the present results suggest that work disability could benefit most from interventions related to recovery from cognitive complaints and less from physically related interventions.

The results presented in Chapter 2 on whiplash and work disability provided an insight into the extent and reach of the consequences of prolonged symptoms. The remaining studies focused on the possible mechanisms contributing to the persistence of whiplash complaints. Knowledge of factors relevant to the prognosis can contribute to a theoretical explanation of the condition but may also contribute in terms of prevention and the development of interventions.

Whiplash and copingCoping can be defined as the way in which someone behaviourally, cognitively and emotionally adapts so as to manage external or internal stressors. After an accident the victim has to cope with several aspects of the event. First of all the victim has to cope with a stressful, potentially life-threatening event. Accidents can lead to physical complaints or to temporary or long-term disability, all demanding adequate coping skills. People may have to cope with a fear that complaints may be prolonged, or even worsen. An active coping style is usually considered preferable, and improving active coping strategies is often advised as a main treatment goal.15 Dysfunctional coping styles could lead to enhanced pain experience or catastrophic interpretations of symptoms, thereby contributing to a bad prognosis.

However, empirical data supporting the validity of this assumption was lacking. Therefore, the study presented in Chapter 3 used a prospective approach to test the assertion that a passive or palliative coping style is related to a poor prognosis in whiplash, whereas a more active coping style is related to a more favourable course.

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The results showed that two weeks after the accident there was no relationship between neck pain and a specific coping style. However, the prognostic results indicate that seeking social support and a less palliative style of coping are related to a shorter duration of neck complaints. Seeking social support is associated with an internal locus of control, meaning that outcomes are thought to be under one’s own control.16 Previous research has shown that patients who believe they can control their pain, who avoid catastrophizing about their condition and who believe they are not severely disabled appear to function better than those who do not. Such beliefs may mediate some of the relationships between pain severity and adjustment.17 This finding suggests that through this pathway there is a possible relationship with expectations and hence causal attribution.

Palliative behaviour is related to seeking distraction, avoiding thinking about the problem and trying to feel better by smoking, drinking or relaxing, and it is known to be positively correlated with feelings of fear and inadequacy.16 It is expected that this fear could originate in irrational expectations of incapacity and chronic complaints.

Whiplash and kinesiophobiaIn relation to low back pain, clinical studies suggest that an excessively negative orientation toward pain catastrophizing and fear of movement/(re)injury (kinesiophobia) are important in the aetiology of chronic symptoms.18 In the fear-avoidance model, catastrophizing leads to pain-related fear, leading in turn to avoidance behaviour, including avoidance of movement and physical activity.19 In low back pain, fear-avoidance beliefs are identified as risk factors for chronic low back symptoms, suggesting that these factors are causal. Furthermore, patients with chronic low back pain who retrospectively reported a sudden traumatic pain onset exhibited higher kinesiophobia than patients who reported that the pain symptoms started gradually.20 In the case of whiplash the onset of pain is often sudden.

Because of the apparent role of kinesiophobia in the transition from acute to chronic low back pain, it is conceivable that it could play a role in recovery from acute neck pain as well. In line with this presumption the results of the one-year prospective study (Chapter 4) showed that kinesiophobia was indeed associated with the duration of neck pain. In accordance with earlier research on kinesiophobia in low back pain, which showed a modest but significant relationship between pain intensity and kinesiophobia, kinesiophobia was found to be significantly related to the intensity of neck pain.18 However, when the severity of the reported physical symptoms was taken into account it appeared that kinesiophobia had no independent relationship with the duration of neck pain after motor vehicle accidents. Kinesiophobia was found to be related to the perceived intensity of neck pain, which explains why its contribution to the duration of neck complaints

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disappears when somatic complaints are added to the model.One possible explanation could be that in neck pain other, anxiety-related factors play

a more prominent role than the rather specific fear of movement/(re)injury. The fact that neck pain starts or is attributed to an often stressful traffic accident clearly distinguishes it from most cases of low back pain and could give rise to more or different forms of anxiety. The sudden, traumatic onset could for instance give rise to stronger somatic beliefs and related fears regarding recovery. Furthermore, it is also conceivable that neck pain in itself is experienced as more frightening than low back pain, which is more common and usually known to be benign in nature. All in all, the results suggest that anxiety is associated with recovery from whiplash but kinesiophobia is not specifically related to the prognosis of post-traumatic neck pain.

Whiplash and post-traumatic stress disorder Post-whiplash syndrome and post-traumatic stress disorder are both relatively common conditions following traffic accidents.21-24 As much as 23 percent of traffic accident victims are reported to have developed post-traumatic stress disorder, which is known to have high psychiatric and medical comorbidity.25-28 Therefore, it has been speculated that there is a relationship between post-traumatic stress disorder and whiplash.29

In accordance with earlier research, and in line with the notion that post-traumatic stress disorder may intensify reported whiplash symptoms, the results presented in Chapter 5 show that post-traumatic stress disorder and its symptoms are more prevalent among car accident victims with post-whiplash syndrome. Perhaps even more importantly, the initial number of hyperarousal symptoms was found to have predictive validity for the persistence and severity of post-whiplash syndrome at six and twelve-months follow-up. This predictive validity cannot be readily attributed to either the severity of the accident or the severity of the sustained injury, as these aspects have been found to be largely independent of the development of post-traumatic stress disorder.30 This result seems to correspond with earlier research that suggests that victims with post-whiplash syndrome generally considered the accident more frightening than did other car accident victims.31 Because perceived threat is of paramount importance in developing post-traumatic stress disorder, it can be speculated that the presence of whiplash complaints is threatening and induces anxiety complaints. This would make the accident more frightening and could subsequently lead to a relatively high number of post-traumatic stress complaints.

The relationship between post-whiplash complaints and post-traumatic stress symptoms was especially pronounced for the hyperarousal symptoms cluster. The mean number of hyperarousal symptoms was three to five times higher among participants with post-whiplash syndrome at one, six and twelve months after the accident. Because the hyperarousal symptom cluster closely resembles anxiety-disorder symptoms, this

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finding may indicate that general anxiety symptoms have an important influence on the perceived severity of post-whiplash syndrome. It is conceivable that whiplash-related anxiety inflates both the hyperarousal symptoms as well as the experienced whiplash complaints, while vice versa, post-traumatic stress symptoms related to the sudden and traumatic origin of physical complaints could also inflate experienced symptoms and fuel whiplash-related anxiety. Hyperarousal symptoms also include hypervigilance, which is known to be correlated with higher reported pain intensity and catastrophic thinking.32 Accordingly, it could be that this results in symptom amplification, fuelling perceived symptom severity, thereby contributing to a process which leads to chronic complaints. One way to test this possibility is to conduct a prospective study of the predictive value of catastrophic thoughts. Such a study was presented in Chapter 6.

It is important to note that the post-traumatic stress disorder hyperarousal symptoms closely resemble complaints such as difficulty concentrating or nervousness, often attributed to post-whiplash syndrome. It is therefore conceivable that these often reported symptoms are actually related to post-traumatic stress. It is also possible that the predictive value of hyperarousal symptoms is due to the fact that these symptoms resemble symptoms associated with post-whiplash syndrome. The intensity of these symptoms is known to be related to the prognosis. The present pattern is consistent with the idea that at least some symptoms usually attributed to post-whiplash syndrome are actually post-traumatic stress symptoms. This further highlights the importance of considering post-traumatic stress disorder, particularly the hyperarousal symptoms, when evaluating post-whiplash symptoms.

Pain catastrophizing in whiplashEarlier work in the context of chronic disorders characterized by unexplained physical complaints, such as chronic low back pain, has provided evidence to suggest that pain catastrophizing and attributional bias are of crucial importance in the development of chronic complaints.33 The research found that the habitual tendency to make catastrophic interpretations of pain is associated with a heightened pain experience in various patient groups.34 Furthermore, catastrophizing has been associated with heightened disability in chronic pain, independent of the level of actual physical impairment.35-37 The study presented in Chapter 5 revealed a relationship between hyperarousal symptoms and the prognosis of neck pain, which could indicate that hypervigilance, which is associated with catastrophizing, also plays a role.

The present results show that, consistent with research into chronic pain, pain catastrophizing is related to concurrent neck disability.37,38 It is feasible that catastrophizing leads to increased physical complaints thereby indirectly contributing to a delayed recovery. However, the results indicate that pain catastrophizing has no independent

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predictive value.

Causal beliefsCausal illness beliefs are defined as the ideas the patient has regarding the cause or origin of the symptoms or illness experienced. In relation to chronic fatigue syndrome it has been found that somatic illness beliefs are associated with increased symptoms and functional impairment, poorer subjective and objective outcomes and poor prognosis.39,40 In a similar vein, dysfunctional causal beliefs may also apply to myogenic neck complaints after motor vehicle accidents. Dysfunctional causal beliefs can be defined as the attribution of the cause of acute myogenic neck complaints to severe, neural or irreparable causes. At the chronic stage of post-whiplash syndrome, somatic or organic beliefs in general can be considered dysfunctional. Causal beliefs are assumed to fuel anxiety regarding the origin and expected course of whiplash symptoms.

To test the role of causal illness beliefs in the persistence of post-whiplash syndrome the Causal Beliefs Questionnaire-Whiplash (CBQ-W) was developed. This CBQ-W is based on clinical experience and the known causes of cervical symptoms – a muscle or ligament injury, a vertebral injury, a neural or cerebral injury and psychological factors. Two questions were added to test specific beliefs – that is, that the cause of the symptoms is ‘whiplash’ and a question regarding the belief that something is irreparably damaged – not specifically related to one of the four dimensions.

The results showed that attributing neck complaints to whiplash has a predictive value over and above the intensity of initial complaints. Therefore, independent of the severity of initial complaints, attributing the perceived complaints to whiplash seems to have a detrimental influence on the prognosis and concurrent disability. This finding not only supports theories regarding the potential influence of culturally embedded causal beliefs, but also has important implications for management and treatment. The present findings suggest that modifying symptom expectations regarding whiplash and altering the causal attribution applied to initial myogenic neck complaints are two possible therapeutic strategies.

The findings are also in line with the ‘nocebo hypothesis’ in which it is proposed that expectations of sickness and the affective state associated with such expectations can cause sickness in the patient.41

The present findings also indicate that attributing initial complaints to psychological factors has additional prognostic value regarding the persistence of disability after one year. This finding is consistent with previously presented research, which showed that early anxiety-related distress was related to delayed recovery from post-whiplash syndrome. Cognitive behavioural interventions may also be helpful to reduce the influence of this type of dysfunctional conviction.

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Finally, it was found that attributing early complaints to vertebral causes is related to persistent complaints at six months and has borderline significance at twelve-month follow-up. This seems especially important since physiotherapy and/or manual therapies concentrating on alleged vertebral causes are quite common in acute whiplash.15 In light of the fact that, by definition, no vertebral abnormalities are found in common whiplash, our results suggest that a therapy which implicitly suggests a vertebral cause could have adverse effects by fuelling dysfunctional beliefs.

Causal beliefs-anxiety modelThe above-mentioned results lead to a new model regarding the development of chronic whiplash complaints. In this ‘causal beliefs-anxiety model’ causal beliefs play an important role because they are the main factor leading from neck pain to the conviction that the pain is caused by ‘whiplash’. They function as the gatekeeper, guarding the entrance to the chronic pain circle. This illness belief is moderated by culturally embedded beliefs. Once the belief is established, catastrophizing fuels the process, leading to anxiety. Increased anxiety levels give rise to increased attention and focus on the perceived symptoms, which are further enhanced by hypervigilance. Increased anxiety levels lead to kinesiophobia and cognitive symptoms due to attention interference, as well as increased muscle tension which leads to increased or continued neck pain. Eventually the process of focusing on perceived pain and anxiety results in central sensitization, in which case nociceptive neurons of pain-modulating systems in the central nervous system are thought to become sensitized.42 Central sensitization provides a theoretical explanation for unexplained chronic pain.

causal attributioncultural embedded beliefs

recovery

neck pain

accident

centralsensitization

increased muscle tension

‘whiplash’

catastrophizingnegative expectationsexternal locus of control

anxiety

increased attention

kinesiophobia, avoidancecognitive interferenceposttraumatic stress disorder

hypervigilance

Figure 1. causal beliefs-anxiety model

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Methodological discussion

Samples studiedThe samples studied consisted of participants who had initiated compensation claim procedures. Since the threshold for starting such procedures is low in the Netherlands, there seems to be no strong reason to suspect that this introduced a bias towards patients whose complaints were more serious.43

Firstly, the damage-report forms that are used for claiming car damage, and which are usually completed within a few days of the accident, contain a section for the names of victims and their complaints. We invited all claimants directly on the basis of these forms, including victims who had not visited an emergency room or sought medical help at the time of the accident.

Secondly, although the insurance company and victims can be seen as opposing parties, most personal injury claims in the Netherlands, even large ones that involve serious injuries, are settled out of court. None of the participants was in actual litigation.

Nevertheless, some international studies have found that compensation is a critical factor to consider when studying post-whiplash syndrome.44-46 Since no Dutch study regarding the influence of claims of any kind on the course and prognosis of whiplash complaints has been conducted, the influence of this factor in the Dutch context is not clear. However, we feel that at least the personal injury claim context should be taken into account when interpreting or generalizing our findings. Furthermore, since the exact nature and expectations of compensation may vary greatly from country to country, we advise caution when extrapolating results from one population to another.

All the findings based on the Causal Beliefs Questionnaire-Whiplash (CBQ-W) should be interpreted with special care since the connotations regarding whiplash are highly culture-dependent. It could well be that this same questionnaire in a different population, especially with different cultural beliefs regarding neck complaints after motor vehicle accidents, would lead to different results.47,48

Emergency room and hospital visitors vs claimantsPrevious research on post-whiplash syndrome has relied predominantly on victims who were recruited from emergency room or hospital visitors, thereby possibly biasing the results towards patients who were more frightened or whose injuries were relatively serious. In the present studies, only a small minority of the car accident victims who were included had actually visited a hospital following the accident. When results show a relationship between the severity of perceived symptoms and the prognosis, as many whiplash-related research does, this recruiting characteristic could be of paramount importance. Furthermore, since the present results reveal that anxiety symptoms are related to the

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prognosis, this also shows that recruiting among emergency room visitors could lead to a possible bias. It is feasible that the emergency room visit itself increases the patient’s anxiety level, especially when transport by ambulance is involved. It is also possible that the actual emergency room visit is not so much dependent on the professional evaluation of a medical professional but on the level of anxiety of the patient. All in all, it is clear that these assumptions provide ample opportunities for future research, especially since the results could have major consequences for acute trauma support on the accident scene as well as in the emergency room.

Self-report dataIn the studies presented, patient data was collected using self-report questionnaires. Although this is a widely used and generally accepted form of data collection, some remarks are in order.It should be acknowledged that any questionnaire-based data holds a risk of self-report bias. While the recruited patients had initiated compensation claim procedures, this gives no reason beforehand to assume that this introduced a bias towards patients whose complaints were more serious. However, although the accompanying letter clearly explained that the research was fully independent from the claim and the results would only be used anonymously and were in no way related to the claim procedure, it cannot be ruled out that this specific context has consequences for the collected data and research results. For instance, it is conceivable that financial arguments gave rise to symptom exaggeration, or a belief that whiplash complaints are more financially beneficial. This cannot be predicted and can only be ruled out by repeating the same research in different populations.

Because the studies presented were limited to self-report data, other research instruments could not be used. Behavioural instruments such as measuring attention bias in cognitive tasks, which would provide further insight into the relationships found and interesting clues for future research, were not feasible in the present context.

Discussion of results: what can we learn from them?The present results regarding work disability and whiplash show that work disability is an important subject when considering the consequences of neck pain after motor vehicle accidents. The results show that concentration complaints are the main symptoms related to the prognosis of work disability. The nature of the work (white or blue-collar) appears to be of minor importance. Therefore, a planned intervention should aim at the cognitive symptoms regardless of the assessed or presumed cognitive load of a certain job. Since neither self-employment nor gender was found to be of relevance, there seems to be no need to incorporate these often-mentioned characteristics into a screening or intervention

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programme. In line with the known research, age was found to be related to the prognosis of work disability. Obviously, age is not a modifiable parameter but should nevertheless be considered when a preventive programme targets high-risk subjects.

The palliative coping style, which was found to be related to the duration of neck pain, includes distractive and avoidant behaviour. It is this avoidant behaviour which provides a link to the fear-avoidance model. Some aspects of this model were investigated. Although kinesiophobia/fear of (re)injury was related to the duration of neck complaints, this relationship diminished when early somatic complaints were considered. From a practical point of view, this symptom-related information is readily available and has been proven to predict the duration of neck complaints over and above kinesiophobia. As a predictive instrument kinesiophobia has no additional value and is therefore not a suitable screening instrument for high-risk patients.

The results show that although kinesiophobia has some interesting relationships (for instance, with neck pain intensity and duration of neck pain when ignoring the intensity of acute somatic complaints) it is not the main variable related to the prognosis. However, the results fuel the idea that anxiety is an important concept in any model describing whiplash.

Post-traumatic stress disorder has been found to be very common after motor vehicle accidents. The present data showed that it is approximately five times more common in patients with neck complaints. Furthermore, the intensity of whiplash-related complaints is associated with concurrent post-traumatic stress disorder symptoms, making it clear that post-traumatic stress disorder is a serious factor which should be considered in all accident victims, but especially in victims exhibiting neck complaints. Inflated physical complaints could give rise to increased catastrophic interpretations and heighten the general anxiety level of an accident victim. The treatment of post-traumatic stress disorder involves examining psychological factors, thereby possibly decreasing somatic attention and hence fixation. Since hyperarousal symptoms, especially, are related to concurrent whiplash complaints as well as to the prognosis of neck complaints, it is clear that characteristic post-traumatic stress disorder symptoms such as avoidance and re-experiencing are of minor importance in whiplash. Because the hyperarousal symptoms closely resemble anxiety-disorder symptoms, this finding seems to indicate that general anxiety symptoms bear an important influence on the perceived severity of whiplash complaints. In line with the results of the research on kinesiophobia, the findings regarding post-traumatic stress disorder symptoms support the view that anxiety can be considered an important factor, although neither of the two anxiety variants can be pointed to as the single responsible factor.

In the fear-avoidance model, threatening illness beliefs and catastrophizing thoughts fuel the dysfunctional process leading to chronic complaints. The present findings

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regarding causal attribution suggest that the diagnosis, independent of the severity of symptoms, is related to the prognosis. Recent research has shown that expectations are important in the prognosis of whiplash.49 Individuals’ expectations about recovery were found to be important in prognosis, even after controlling for symptom severity. This interesting finding suggests that future interventions should aim to provide more realistic expectations. Another interesting question concerns the origins of these negative and catastrophic expectations. The present results showed that the patients’ early opinion regarding the diagnosis ‘whiplash’ may be of paramount importance here. The results suggest that the term ‘whiplash’ is associated with negative connotations and dysfunctional beliefs regarding the course and prognosis. These dysfunctional beliefs could very well fuel negative thoughts regarding recovery, thereby providing an explanation for the development of negative expectations and providing an even better target for future interventions.

Therefore, the findings suggest modifying symptom expectations regarding whiplash and altering the causal attribution of initial myogenic neck complaints as two possible therapeutic strategies.

Altering symptom expectation is a cultural process that should be employed at the population level, typically requiring educational campaigns and professional guidelines. Although this could lead to a broad and definitive strategy at the population level, it is to be expected that this will be a slow process, taking several years. Altering causal beliefs is an individual process that can be readily employed by developing a cognitive behavioural intervention aimed at modifying these specific causal convictions.

The early opinion or conviction is at least partly formed by physicians and other health workers who make the diagnosis. In light of the fact that the conviction of suffering from ‘whiplash’ is apparently related to a poor prognosis, a simple and easy first step in preventing the development of chronic neck complaints appears to be to no longer use the term ‘whiplash’. ‘Whiplash’ is a strange diagnosis, originally meant to describe a specific movement of the head. It is associated with a large number of atypical symptoms and apparently has a bad name in certain countries, fuelled by catastrophic patient stories and other media attention, which is often commercially driven and aimed more at reaching and entertaining large groups of readers or viewers than providing genuine and correct information.

The next step in early management would be to supply the patient with correct information regarding the complaints and to eliminate catastrophic beliefs regarding the diagnosis, course and prognosis. It is to be expected that at an early stage a limited cognitive intervention could lead to correction of an otherwise catastrophic course.

When complaints persist for a longer period (for example, three months) a structured cognitive behavioural intervention may be employed. Considering the relatively early

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stage, it is conceivable that this treatment would be provided by a general practitioner. Increasingly, general practitioners are receiving specialized training in providing cognitive behavioural therapy interventions to deal with unexplained somatic symptoms.50

Patients suffering from persistent symptoms should be referred to specialized centres aimed at treating unexplained somatic complaints. Future research and where to go from hereThe present research project showed that work disability is a very relevant factor in the context of neck pain after motor vehicle accidents. The costs of sick leave and disability pensions are higher than the costs of acute medical care, demonstrating that future research should also consider absenteeism from work and work disability, alongside somatic parameters such as complaint severity.

The relevance of coping strategies, the fear-avoidance model, catastrophizing and causal beliefs with regard to work disability, remain unclear but they should all be targets for future research, to gain an insight into the relevance of these factors in relation to work disability.

The important finding - that the prognosis of neck complaints after a motor vehicle accident is related to the early causal belief that the symptoms are the result of whiplash - gives rise to several directions for future research. Since the connotations regarding whiplash are highly culture-dependent, it could well be that the Causal Beliefs Questionnaire-Whiplash (CBQ-W) would lead to different results in a different population, especially when different cultural beliefs regarding neck complaints after motor vehicle accidents exist. Some research in this direction has already been conducted.51-53 However, it would be beneficial to investigate expectations and beliefs regarding whiplash in relation to perceived severity, course and prognosis in different populations. It would also be interesting to investigate causal illness beliefs regarding whiplash complaints in emergency room visitors and non-emergency room visitors, to test the assumption that emergency room visitors have stronger somatic beliefs regarding their symptoms, or higher anxiety levels. In addition, it seems worthwhile to investigate whether ambulance transport and an emergency room visit leads to increased anxiety levels. Furthermore, it seems important to learn whether the suggested pathway from dysfunctional causal illness beliefs to negative expectations is indeed correct. This would provide further evidence and steering in the development of future interventions and prevention programmes.

The results of interventions aimed at changing causal beliefs should be investigated. It would be interesting to learn if causal beliefs can be changed, and by what kind of intervention. The effects of interventions aimed at changing causal beliefs should be investigated in terms of the influence on patients’ expectations regarding course and prognosis, as well as on the actual prognosis itself.

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General conclusionsThe present results clearly show that whiplash complaints should be taken seriously. Not only in terms of delayed recovery but also in terms of work disability. The studies have shown that anxiety and anxiety-related symptoms form an important part of the whiplash complaints presented, although they are not related to recovery. Nevertheless, the results show that post-traumatic stress disorder and pain catastrophizing inflate concurrent whiplash complaints. In addition, post-traumatic stress disorder is five times more prevalent among patients with neck pain, illustrating the importance of considering post-traumatic stress symptoms when evaluating or treating patients with whiplash.

A palliative coping style and hyperarousal symptoms were found to have prognostic value for the persistence of whiplash complaints. In addition, early causal beliefs, including the belief that complaints are caused by ‘whiplash’, are related to more severe concurrent complaints as well as a poor prognosis for whiplash symptoms. These findings suggest that the early causal beliefs regarding symptoms are of paramount importance, providing a target for future interventions that aim to provide realistic expectations and decrease catastrophic and dysfunctional causal beliefs.

Because the present results are essentially correlational in nature no clear conclusions can be drawn regarding the causal status of the variables studied. Controlled studies specifically aimed at causal beliefs and expectations may not only be of important clinical value but may also allow more definitive conclusions to be revealed regarding the causal role of specific psychological factors in the recovery from whiplash complaints.

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The term whiplash originally referred to a specific movement of the head due to a rear-end collision. Later the term was used to refer to the complex of symptoms itself. The main feature of whiplash is neck pain. There may be a wide variety of other symptoms accompanying the neck pain, but the presence of neck pain is usually considered necessary for the diagnosis of whiplash. The accident is still the prerequisite to the complaints but has become defined in ever broader terms.

In 1995 the Quebec Task Force introduced the term Whiplash Associated Disorder (WAD) to capture the wide variety of symptoms attributed to whiplash by that time. Other terms used in the literature are late or post-whiplash syndrome, which indicate symptoms after a whiplash accident or movement. Over recent decades chronic neck pain has become a common complaint after motor vehicle accidents.

Although the majority of patients show spontaneous recovery within the first few months of a traffic accident, in as many as 40 percent of cases, acute complaints lead to a chronic syndrome with neck pain often accompanied by cognitive complaints. To date no somatic injury has been identified that can explain the chronic symptoms, which are thereby generally identified as medically unexplained, and this has given rise to various views, studies and controversies regarding their possible somatic, psychological or psychosomatic nature.

In research on low back pain it is well established that psychological factors are related to chronic pain and disability. Given the fact that in chronic whiplash there is also chronic musculoskeletal pain related to the spine without identification of a somatic cause, it seems reasonable to assume that psychological parameters can play a role in the aetiology and course of persisting whiplash symptoms. Therefore, the major aim of the studies presented in this thesis was to explore the relationships between psychological determinants and the prognosis of whiplash symptoms, as well as the consequences of these complaints for work disability.

Traffic accident victims who had initiated compensation claim procedures for personal injury with a Dutch insurance company were asked to participate in the various studies. Participants were assessed at one, six and twelve months after their accident, using relevant questionnaires. The longitudinal data was used to analyse predictive characteristics and the temporal order of events. To keep the total number of questionnaires small, and thereby ensure a sufficient response, different samples were used for each study with the exception of the study on work disability (Chapter 2), in which the sample was formed by combining the other four.

Chapter 1 provides a general introduction and overview of possible psychological parameters involved in whiplash. It concludes with an outline of the thesis.

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Work disabilityWork disability is one of the major financial factors in liability claims relating to whiplash complaints. Furthermore, previous research has shown that sick leave and disability pension costs are much higher than the costs of acute medical care, demonstrating that these parameters are of paramount importance when evaluating the consequences of neck pain after motor vehicle accidents. However, the previous studies on work disability related to whiplash are very heterogeneous, mainly due to cultural diversity in the conceptualization of work disability and social security systems, and they are often limited in sample size and consequently show wide variability in results. To gain an insight into the consequences of whiplash complaints for work disability, a prospective cohort study, described in Chapter 2, was designed to investigate the relationship between whiplash, its symptoms and work-related factors in a group of 879 participants with neck pain after a motor vehicle accident. These participants were followed up after six and twelve months.

A total of 58.8 percent of the population with neck complaints in our sample was work-disabled after the accident. Age and concentration complaints were important independent predictors of long-lasting work disability, whereas no evidence emerged to indicate that the degree of manual labour (blue or white-collar work) or educational level was involved in persistent work disability. The results suggest that whiplash-induced work disability is a highly frequent condition that could benefit most from interventions related to recovery from cognitive complaints and less from physically related interventions.

Coping styleCoping can be defined as the way in which someone behaviourally, cognitively and

emotionally adapts so as to manage external or internal stressors. The accident itself, as well as the pain afterwards, can be considered an external stressor and therefore as requiring coping efforts. Dysfunctional coping styles might lead to enhanced pain experience or catastrophic interpretations of symptoms, thereby contributing to a bad prognosis. To gain an insight into the role of coping style in the generation and maintenance of whiplash symptoms, the prospective cohort study described in Chapter 3 investigated the relationship between coping style and the course of physical and cognitive symptoms in a cohort of 363 participants with neck pain after a motor vehicle accident. Participants were followed up after six and twelve months. The coping styles were determined using the Utrecht Coping List. The duration of neck complaints was measured from the time of the accident and from the time of filling in the first questionnaire. Survival analysis was used to study the association between the duration of neck complaints and the explanatory variables. The duration of the neck complaints was found to be associated with gender, palliative reaction, and the seeking of social support, which was one of the defined coping styles.

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KinesiophobiaThe fear-avoidance model was developed to provide an integrated model of risk factors known to be associated with chronic pain. Central to this model is the concept of fear of pain. An excessively negative orientation towards pain catastrophizing and fear of movement/(re)injury (kinesiophobia) are important in the aetiology of chronic symptoms. Dysfunctional coping styles could fuel anxiety and psychosomatic mechanisms. Anxiety related to avoidance, such as that found in kinesiophobia or fear of (re)injury could play an important role in prolonging whiplash symptoms, considering their apparent relevance to other chronic pain syndromes.

To gain an insight into the role of kinesiophobia in the course of whiplash symptoms, the prospective cohort study described in Chapter 4 investigated the predictive value of early kinesiophobia in relationship to the course of physical and cognitive symptoms in a cohort of 367 participants with neck pain after a motor vehicle accident. Kinesiophobia was assessed using the Tampa Scale of Kinesiophobia (TSK-DV). Follow-up questionnaires were administered, six and twelve months after the collision. Survival analysis was used to study the relationship between the duration of neck symptoms and kinesiophobia as well as physical and cognitive complaints.In a regression model that did not include physical and cognitive complaints, kinesiophobia was found to be related to a longer duration of neck pain. However, when symptom-related information was entered into the model, the effect of kinesiophobia did not reach statistical significance.

It was therefore concluded that, although a higher score on the TSK-DV is associated with a longer duration of neck symptoms, information on early kinesiophobia does not improve the ability to predict the duration of neck pain after motor vehicle collisions. However, the results suggest that anxiety is associated with recovery from whiplash.

Post-traumatic stress symptomsImportantly, neck complaints in whiplash are caused by an accident, or at least experienced after one. An accident is often a frightening or terrifying experience which can lead to anxiety. Post-traumatic stress disorder is a specific anxiety related to the experience of a life-threatening event. Post-whiplash syndrome and post-traumatic stress disorder are both relatively common conditions following traffic accidents. Post-traumatic stress disorder is known to have high psychiatric and medical comorbidity. Post-traumatic stress symptoms may give rise to increased anxiety and vigilance levels, thereby fuelling catastrophic, dysfunctional interpretations of acute neck pain. It could therefore be expected that the post-traumatic stress anxiety symptoms are related to the severity of somatic complaints and could play a role in the prognosis of neck pain after motor vehicle accidents.

To investigate this hypothesis a prospective cohort study of 240 participants with

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neck pain after a motor vehicle accident was designed and presented in Chapter 5. The relationship between post-traumatic stress disorder (and its symptoms) and the severity and course of whiplash at one, six and twelve months was presented. The Self-Rating Scale for post-traumatic stress disorder (SRS-PTSD) was used to assess the post-traumatic stress symptoms.

Post-traumatic stress disorder was related to the presence and severity of concurrent post-whiplash syndrome. More specifically, the intensity of hyperarousal symptoms that were related to post-traumatic stress disorder at one month was found to have predictive validity for the persistence and severity of post-whiplash syndrome at six and twelve-months follow-up. The results therefore suggest that post-traumatic stress disorder hyperarousal symptoms have a detrimental influence on the recovery from and severity of whiplash complaints following car accidents.

Pain catastrophizing and causal illness beliefsPain catastrophizing refers to an exaggerated negative orientation towards actual or anticipated pain. It has been associated with heightened disability in chronic pain, independent of the level of actual physical impairment.

Causal illness beliefs can be defined as the patient’s ideas about the origin or cause of the symptoms or illness experienced. The causal beliefs of the patient seem very relevant in relation to the persistence of complaints when no organic cause has been identified. When patients are diagnosed with an illness they generally develop an organized pattern of beliefs about their condition. These illness perceptions or cognitive representations directly influence behaviour parameters and the emotional response. Causal beliefs lead to expectations regarding the course of complaints. Negative expectations could give rise to avoidant behaviour, leading to avoidance of movement and physical activity, ultimately leading to disuse and a heightened state of fear.

In the large body of research on whiplash its cultural dependence is often the subject of discussion. The fact that whiplash only seems to occur in a restricted number of countries and runs an apparently different course in various countries seems to imply that the cultural context is a major factor to be considered. However, the actual nature of that cultural context has never been subject to research. Causal illness beliefs are shaped by cultural factors. Beliefs and expectations regarding whiplash were found to vary profoundly across countries, thereby providing a cultural parameter relevant to the prognosis of muscular neck pain.

Chapter 6 describes a prospective cohort study of 140 participants with neck pain after a motor vehicle accident, and was designed to examine the role of pain catastrophizing and causal beliefs with regard to the severity and persistence of neck complaints after motor vehicle accidents. Individuals involved in traffic accidents were sent questionnaires

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containing the Neck Disability Index (NDI), the Pain Catastrophizing Scale (PCS) and the Causal Beliefs Questionnaire-Whiplash (CBQ-W). Complaints were monitored using additional questionnaires administered six and twelve months after the accident.

The study found that pain catastrophizing and causal beliefs were related to the severity of concurrent whiplash symptoms. The severity of initial complaints was related to the severity and persistence of whiplash complaints. However, attributing initial neck complaints to whiplash was also found to predict the persistence of disability at six and twelve-months follow-up.

The results suggest that causal beliefs may play a major role in the perceived disability and course of neck complaints after motor vehicle accidents, whereas pain catastrophizing is predominantly related to concurrent disability. The current findings are consistent with the view that an early conviction that neck complaints are caused by the medico-cultural entity of ‘whiplash’ has a detrimental effect on the course of symptoms.

Finally, in Chapter 7 the results of the various studies are integrated and discussed. A summary of the main results and a general discussion of the findings is presented. A Causal Beliefs-Anxiety Model is proposed, combining the results in an integrated framework. In this model, causal beliefs play an important role because they are the main factor leading from neck pain to the conviction that the pain is caused by ‘whiplash’. They function as the gatekeeper, guarding the entrance to the chronic pain circle. This illness belief is moderated by culturally embedded beliefs. Once the belief is established, catastrophizing fuels the process, leading to anxiety and increased attention to and focus on the perceived symptoms. Eventually the process of focusing on perceived pain and anxiety results in central sensitization, which provides a theoretical explanation for unexplained chronic pain.

The chapter also discusses methodological issues. Although there is no apparent reason to suspect that the samples studied, in which participants were recruited on the basis of their liability claims, contained a bias towards patients whose complaints were more serious, the personal injury claim context should nevertheless be taken into account when interpreting or generalizing the findings.

Since the connotations regarding whiplash are highly culture-dependent, the extrapolation of culture-related results from one population to another should be undertaken with care. It could well be that causal beliefs regarding whiplash differ from one population or country to another. Furthermore, since the samples studied consisted mainly of participants who had not visited an emergency room, this aspect should be taken into account when comparing the results with other studies.

The results suggest that modifying symptom expectations regarding whiplash and altering the causal attribution of initial myogenic neck complaints are two possible therapeutic strategies. Altering symptom expectation is a cultural process that should

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be employed at the population level, typically requiring educational campaigns and professional guidelines, whereas altering causal beliefs is an individual process that can be readily undertaken by developing a cognitive behavioural intervention aimed at modifying these specific causal convictions.

Because the present results are essentially correlational in nature, no clear conclusions can be drawn regarding the causal status of the variables studied. Controlled studies specifically aimed at causal beliefs and expectations may not only be of important clinical value but may also allow more definitive conclusions to be drawn regarding the causal role of specific psychological factors in the recovery from whiplash complaints.

Future research should use functional outcome parameters such as work disability. Furthermore, the finding – that the prognosis of neck complaints after a motor vehicle accident is related to the early causal belief that the symptoms are the results of whiplash – gives rise to several directions for future research. In addition, the proposed Causal Beliefs-Anxiety Model provides ample suggestions for future research looking for further evidence that can steer the development of future interventions and prevention programmes.

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De term whiplash verwijst naar een specifieke beweging van het hoofd na een kop-staart botsing. Later werd de term gebruikt voor een complex van symptomen. Het hoofdkenmerk van whiplash is nekpijn. Alhoewel veel andere klachten aanwezig kunnen zijn, wordt de aanwezigheid van nekpijn gewoonlijk als voorwaarde voor de diagnose whiplash beschouwd. Een ongeval gaat aan de klachten vooraf, maar is in de loop der tijd steeds breder gedefinieerd.

In 1995 introduceerde the Quebec Task Force de term Whiplash Associated Disorder (WAD), om daarmee het gehele complex aan symptomen te beschrijven die tegen die tijd aan whiplash werden toegeschreven. Andere termen die in de literatuur wel worden gebruikt zijn laat- of post-whiplash syndroom. In de afgelopen tientallen jaren is chronische nekpijn na een ongeval een veel voorkomende klacht geworden.

Alhoewel de meerderheid van patiënten in de eerste maanden na het ongeval spontaan herstellen, kunnen tot 40% van de mensen met acute klachten chronisch klachten houden met naast nekpijn ook vaak cognitieve klachten. Tot op heden is geen lichamelijk letsel gevonden die de chronische klachten kan verklaren, die daarmee dan ook als medisch onverklaard worden gezien. Dit geeft aanleiding tot veel verschillende visies, onderzoeken en controverses over de mogelijke lichamelijke, psychologische of psychosomatische origine.

Uit onderzoek naar lage rugpijn is bekend dat psychologische factoren een belangrijke rol spelen bij chronische pijn. Gezien het feit dat er in het geval van chronische whiplash ook sprake is van chronische pijn, zonder aanwijsbare lichamelijke oorzaak, gerelateerd aan het bewegingsapparaat, lijkt het aannemelijk dat psychologische factoren ook een rol kunnen spelen in het ontstaan en persisteren van whiplash klachten. De in dit proefschrift gepresenteerde studies onderzoeken psychologische factoren in relatie tot de prognose van whiplash klachten, naast de gevolgen van die klachten voor arbeidsgeschiktheid.

Slachtoffers van verkeersongevallen die een letselschadeprocedure startten bij een verzekeringsmaatschappij werd gevraagd aan onderzoek mee te werken. Zij werden 1, 6 en 12 maanden na het ongeval gevraagd vragenlijsten in te vullen. Deze longitudinale gegevens werden gebruikt om voorspellende karakteristieken te analyseren. Om voldoende response te genereren werden vier verschillende onderzoeken verricht waarmee het totale aantal vragenlijsten per onderzoek klein kon worden gehouden. Het onderzoek naar whiplash en arbeidsongeschiktheid (hoofdstuk 2) vond plaats door de andere vier onderzoeksgroepen samen te voegen.

Hoofdstuk 1 bevat een algemene introductie en overzicht van mogelijke psychologische factoren die een rol kunnen spelen bij whiplash. Het besluit met een overzicht van het proefschrift.

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Arbeidsongeschiktheid

De kosten van arbeidsongeschiktheid vormen één van de belangrijkste financiële onderdelen van letselschade claims op basis van whiplash klachten. Verder heeft eerder onderzoek duidelijk gemaakt dat de kosten van arbeidsongeschiktheid als gevolg van nekklachten hoger zijn dan de kosten van medische behandeling, waarmee duidelijk wordt dat arbeidsongeschiktheid van groot belang is bij het onderzoeken van de gevolgen van nekpijn na verkeersongevallen. De resultaten van eerder verricht onderzoek naar arbeidsongeschiktheid en whiplash zijn erg heterogeen, voornamelijk als gevolg van kleine onderzoeksgroepen en culturele verschillen in sociale verzekeringen en de definitie van arbeidsongeschiktheid.

In hoofdstuk 2 wordt een prospectieve cohort studie beschreven die werd opgezet om inzicht te krijgen in de gevolgen van whiplash voor arbeidsongeschiktheid. In deze studie, met meetmomenten 1, 6 en 12 maanden na het ongeval, werd in 879 deelnemers de relatie tussen arbeidsongeschiktheid en whiplash klachten onderzocht.

In totaal was 58.8% van de deelnemers arbeidsongeschikt na het ongeval. Leeftijd en concentratie klachten na 1 maand waren belangrijke, onafhankelijke voorspellers van langdurende arbeidsongeschiktheid. Voor de invloed van fysiek belastend werk of opleidingsniveau op de duur van de arbeidsongeschiktheid werd geen bewijs gevonden. Uit de resultaten blijkt dat arbeidsongeschiktheid als gevolg van whiplash veel voorkomt en waarschijnlijk het meest zal kunnen profiteren van interventies gericht op herstel van cognitieve klachten in plaats van gericht op herstel van fysiek functioneren.

Coping stijl

Coping kan worden gedefinieerd als de wijze waarop iemand gedragsmatig, cognitief en emotioneel omgaat met in- en externe stressoren. Zowel het ongeval als de pijn nadien kunnen worden gezien als externe stressoren en vereisen daarom coping strategieën. Disfunctionele copingstijlen kunnen bijdragen aan een slechte prognose als gevolg van toegenomen pijnbeleving en catastroferende interpretaties van klachten.

In Hoofdstuk 3 wordt een prospectieve cohort studie beschreven die werd opgezet om inzicht te krijgen in de rol van copingstijlen en het ontstaan en persisteren van whiplash klachten. In deze studie werd in 363 deelnemers met nekpijn na een auto-ongeval de relatie tussen copingstijlen en het beloop van fysieke en cognitieve klachten onderzocht. De copingstijl werd gemeten met de Utrechtse Copinglijst (UCL). Met behulp van survival analyse technieken werd de relatie tussen de duur van nekklachten en de verklarende variabelen onderzocht. Uit de resultaten bleek dat vrouwen langer

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nekklachten hielden dan mannen. Verder duurden nekklachten langer bij mensen met een palliatieve copingstijl. Bij mensen met het zoeken van sociale steun als coping stijl duurden de nekklachten juist relatief korter.

Kinesiofobie

Het angst-vermijdingsmodel is een geïntegreerd model van risicofactoren geassocieerd met chronische pijn. Centraal in dit model staat het concept van angst voor pijn. Een excessieve negatieve oriëntatie richting pijncatastroferen en bewegingsangst zijn belangrijk factoren in het ontstaan van chronische klachten. Disfunctionele copingstijlen kunnen angst en psychosomatische processen verder versterken. Gezien het belang van angst gerelateerde vermijding, zoals bewegingsangst (kinesiofobie) in andere chronische pijnsyndromen, kan deze mogelijk ook een belangrijke rol spelen bij het in standhouden van whiplash klachten.

In hoofdstuk 4 wordt een prospectieve cohort studie beschreven die werd opgezet om de relatie tussen kinesiofobie en het beloop van whiplash te onderzoeken. In deze studie werd in 367 deelnemers met nekpijn na een auto-ongeval de relatie tussen kinesiofobie en het beloop van fysieke en cognitieve klachten onderzocht. Kinesiofobie werd gemeten met de “Tampa Scale of Kinesiophobia Dutch version” (TSK-DV).

Met behulp van survival analyse technieken werd de relatie tussen de duur van de nekklachten en kinesiofobie en andere fysieke en cognitieve klachten onderzocht. In een regressie model zonder fysieke en cognitieve klachten bleek de bewegingsangst na 1 maand samen te hangen met langer durende nekpijn. Maar wanneer andere klachten, zoals de ernst van de na één maand ervaren nekpijn, aan het model werden toegevoegd, bleek het effect van bewegingsangst niet meer statistisch significant.

De conclusie is dat een hogere score op de TSK-DV na 1 maand weliswaar is geassocieerd met langer durende nekklachten, maar dat dit klinisch geen toegevoerde waarde heeft voor het voorspellen van de duur van nekpijn na een auto-ongeval. De resultaten suggereren echter wel dat angst mogelijk een rol speelt bij herstel van whiplash.

Posttraumatisch stress syndroom

Per definitie worden nekklachten bij whiplash ervaren na een ongeval. Een ongeval is vaak een beangstigende of angstaanjagende ervaring. Posttraumatisch stresssyndroom (ptss) is een specifieke angststoornis gerelateerd aan het ervaren van een (levens)

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bedreigende gebeurtenis. Post-whiplash syndroom en posttraumatisch stresssyndroom zijn relatief veel voorkomende beelden na verkeersongevallen. Van het posttraumatisch stresssyndroom is bekend dat deze een hoge psychiatrische en medische comorbiditeit kent. Posttraumatische stressklachten kunnen leiden tot verhoogde angst en gevoeligheid, die vervolgens catastroferende, disfunctionele interpretaties van nekklachten kunnen versterken. Het is daarom te verwachten dat posttraumatische stressklachten zijn gerelateerd aan de ernst van ervaren nekklachten en een rol kunnen spelen in de prognose van nekpijn na auto-ongevallen.

In hoofdstuk 5 wordt een prospectieve cohort studie beschreven die werd opgezet om deze hypothese te onderzoeken. In deze studie werd in 240 deelnemers de relatie tussen posttraumatische stressklachten en de ernst en beloop van whiplash klachten onderzocht. Posttraumatische stressklachten werden gemeten met de Self-Rating Scale for post-traumatic stress disorder (SRS-PTSD).

Uit de resultaten bleek dat posttraumatisch stresssyndroom was gerelateerd aan de aanwezigheid en ernst van gelijktijdig voorkomende whiplash. Met name verhoogde prikkelbaarheid 1 maand na het ongeval bleek gerelateerd te zijn aan persisterende en meer ernstige whiplash klachten na 6 en 12 maanden. De resultaten suggereren dat posttraumatisch stress gerelateerde verhoogde prikkelbaarheid een nadelige invloed heeft op herstel en ervaren ernst van whiplash klachten na een auto-ongeval.

Pijn catastroferen en causale attributies

Met pijn catastroferen wordt een overdreven negatieve oriëntatie richting actuele of verwachtte pijn bedoelt. Het is geassocieerd met grotere invaliditeit bij chronische pijn, onafhankelijk van de mate van fysiek bepaalde invaliditeit.

Causale attributies kunnen worden gedefinieerd als de ideeën die een patiënt zelf heeft over de oorzaak van ervaren klachten, en waar de klachten aan worden toegeschreven. Causale attributies lijken erg relevant bij persisterende klachten zonder aantoonbare somatische oorzaak. Wanneer bij patiënten een aandoening wordt gediagnosticeerd, vormt zich doorgaans een patroon van gedachten en attributies over de aandoening. Deze ziekte percepties of cognitieve representaties beïnvloeden gedragsmatige en emotionele reacties. Causale attributies leiden tot verwachtingen ten aanzien van het beloop van klachten. Negatieve verwachtingen kunnen leiden tot vermijdingsgedrag, zoals het mijden van beweging of lichamelijke activiteit, wat uiteindelijk aanleiding kan geven tot “disuse” en een verhoogde staat van angst.

In de literatuur over whiplash is de invloed van culturele factoren vaak onderwerp van discussie. Het feit dat whiplash alleen voor lijkt te komen in bepaalde landen en bovendien in verschillende landen een verschillend beloop kent, impliceert dat de

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culturele context van groot belang is. Maar de feitelijke aard van die culturele context is nog nooit onderzocht. Causale attributies worden gevormd door culturele factoren. De verwachtingen van whiplash blijken tussen landen sterk te variëren, en vormt daarmee een culturele parameter met potentiële relevantie voor de prognose.

Hoofdstuk 6 beschrijft een prospectief cohort onderzoek, met 140 deelnemers met nekpijn na een auto-ongeval. In deze studie werd de rol van pijn catastroferen en causale attributies in relatie tot de ernst en persisteren van whiplash klachten onderzocht. De voorspellende variabelen werden o.a. gemeten met de “Pain Catastrophizing Scale” (PCS) en de “Causale Beliefs Questionnaire – Whiplash” (CBQ-W), die voor deze studie werd ontwikkeld.

Pijn catastroferen en causale attributies bleken gerelateerd aan de ernst van gelijktijdige whiplashklachten. De ernst van initiële klachten was gerelateerd aan de ernst en persisteren van whiplash klachten. Het toeschrijven van initiële nekklachten aan whiplash bleek gerelateerd aan het persisteren van klachten na 6 en 12 maanden. De resultaten suggereren dat causale attributies een belangrijke rol kunnen spelen in ervaren onvermogen en het beloop van whiplash klachten. De bevindingen zijn in overeenstemming met de visie dat een vroege overtuiging dat klachten het gevolg zijn van de medisch-culturele entiteit whiplash een nadelige invloed heeft op het beloop van de klachten.

Tot slot worden in hoofdstuk 7 de resultaten van de verschillende studies geïntegreerd

en besproken. Het causale-angst model wordt voorgesteld. Hierin zijn de resultaten in een geïntegreerd model opgenomen. In dit model spelen causale attributies een voorname rol, omdat zij de belangrijkste factor vormen die van nekpijn leidt naar de overtuiging dat de nekpijn wordt veroorzaakt door “whiplash”. Zij vormen de poortwachter die de entree tot de chronische pijn cirkel bewaakt. Deze causale attributies worden gevormd door cultureel verankerde overtuigingen. Als de overtuiging eenmaal is gevormd, voedt catastroferen het proces, leidend tot angst en toegenomen aandacht en focus op de ervaren klachten. Uiteindelijk kan het proces van focus op ervaren pijn en angst tot centrale sensitisatie leiden. Centrale sensitisatie biedt een theoretische verklaring voor het ervaren van onverklaarde chronische pijn.

Verder worden methodologische aspecten besproken. Alhoewel er geen duidelijke reden is te vermoeden dat de onderzochte groepen, bestaande uit deelnemers die een letselschade procedure hadden gestart, een tendens vertonen tot ernstiger klachten, dient toch bij de interpretatie en generalisatie van de resultaten met de letselschade context van het onderzoek rekening gehouden te worden.

Aangezien ideeën over whiplash tussen culturen sterk kunnen verschillen, dient het extrapoleren van cultureel afhankelijke resultaten met grote voorzichtigheid te

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geschieden. Het kan zeer goed zijn dat causale attributies van whiplash afwijkend zijn in verschillende culturen of landen. Verder, dient bij het vergelijken van de gepresenteerde studies met ander onderzoek rekening te worden gehouden met het feit dat een groot deel van de onderzochte deelnemers geen spoedeisende hulp of ehbo afdeling heeft bezocht na het ongeval.

De resultaten van dit proefschrift suggereren dat een goede therapeutische strategie kan worden gevormd door het veranderen van causale attributies en verwachtingen ten aanzien van de initiële myogene klachten. Het veranderen van verwachtingen is voornamelijk een cultureel proces dat zou moeten worden ingezet op populatie niveau, met behulp van voorlichtingscampagnes en professionele richtlijnen. Het veranderen van causale attributies is meer een individueel proces, wat snel kan worden toegepast met behulp van een cognitief gedragsmatige interventie gericht op het aanpassen van specifieke overtuigingen.

Omdat de gepresenteerde resultaten correlationeel van aard zijn, kan geen uitspraak worden gedaan over de causale bijdrage van de onderzochte variabelen. Gecontroleerde studies, specifiek gericht op causale attributies en verwachtingen kunnen niet alleen van belangrijke klinische waarde zijn, maar kunnen tevens leiden tot meer definitieve conclusies aangaande de oorzakelijke rol van specifieke psychologische factoren in het herstel van whiplash klachten.

Toekomstig onderzoek zou meer gebruik moeten maken van functionele uitkomst parameters zoals arbeidsongeschiktheid. Verder geeft de bevinding dat de prognose van nekklachten na een auto-ongeval is gerelateerd aan de vroege overtuiging dat de klachten het gevolg zijn van whiplash, aanleiding tot verschillende richtingen voor onderzoek. Het voorgestelde causale-angst model geeft meerdere mogelijkheden voor verder onderzoek, die mogelijk kunnen bijdragen aan adequate interventies en preventie programma’s.

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Dankwoord

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Dankwoord

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Dankwoord

Een zogenoemd extern promotietraject is meestal een langdurige zaak en kent niet zelden, zo heb ik me laten vertellen, geen succesvolle afronding. Dat dit traject toch tot een resultaat heeft geleid is te danken aan veel mensen. Traditiegetrouw worden die bedankt in het dankwoord. Ik ben niet iemand voor een lang dankwoord, en houd het dan ook kort.

Terugkijkend is deze promotie eigenlijk begonnen in 1998 toen ik besloot, naar voorbeeld en op suggestie van Jerry Spanjer, om de afsluitende scriptie van de specialisatie tot arts voor Arbeid en Gezondheid in de vorm van een wetenschappelijk artikel te gieten. Tegen die tijd kwam ik in mijn werk als medisch adviseur letselschade bij Univé veel met mensen met nekklachten in aanraking, die ik daarvoor slechts sporadisch had gezien. Chronische pijn en niet objectiveerbare aandoeningen hadden al langer mijn interesse, dus een onderwerp voor onderzoek was daarmee geboren.Het bleek een onderwerp met vele kanten en meer dan voldoende inhoud om mij de afgelopen tien jaar aan het werk te houden. Univé gaf mij gelegenheid voor het verzamelen van onderzoeksgegevens en was later bereid haar ‘maatschappelijk ondernemen beleid’ te concretiseren door mij enige uren per week vrij te maken voor medisch wetenschappelijk onderzoek en onderwijs aan medisch studenten.

Jan Jaspers, wiens naam ik kende van publicaties over whiplash en posttraumatische stressstoornis, ontving mij gastvrij en was zeer bereid mee te denken en te schrijven aan nieuw onderzoek. Na altijd inspirerend contact met Johan Groothoff in 2002, was de promotie ambitie geboren. Via een bezoek aan Johan Vlaeyen kwam Peter de Jong op mijn pad, toen net vanuit Maastricht professor geworden in Groningen. Ook hij ontving mij gastvrij, was zeer enthousiast en wilde graag meedenken en schrijven aan mijn onderzoeksideeën. Mijn ‘promotie-team’ was daarmee geboren. Gevieren hebben we dan nu de eindstreep gehaald.

In die 10 jaar zijn er honderden patiënten geweest die belangeloos hebben meegewerkt aan het onderzoek, in de hoop en verwachting mee te werken aan verbetering van diagnostiek, zorg of inzicht in klachten die hen soms ernstig raakten. Ik hoop dat het hier gepresenteerde onderzoek een bijdrage zal kunnen leveren aan het verbeteren van inzicht en daarmee het voorkomen of behandelen van die klachten en dat in die zin hun medewerking zinvol is geweest.

Gegevens moeten worden geanalyseerd. In het begin heb ik veel gehad aan het statistische werk van Vaclav Fidler. Later ging ik meer op eigen benen staan met regelmatige ondersteuning van Roy Stewart.

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Het schrijven van een wetenschappelijk artikel blijkt weerbarstig te zijn. Dit geldt misschien wel des te meer voor iemand die het naast ander dagelijks werk moet doen. Menig vrije avond, zonnige zomerdag en vroege zondagochtend, heb ik doorgebracht achter mijn computerscherm, met soms uiteindelijk maar enkele zinnen of alinea’s als resultaat. En natuurlijk was het soms moeilijk de motivatie op te blijven brengen. En natuurlijk ben ik boos geweest op afwijzingen van tijdschriften die niet voldoende inzicht hadden om het niveau van het aangeboden werk op zijn waarde te schatten. Maar de voldoening van een gepubliceerd artikel maakt veel goed en - het menselijke geheugen is onbetrouwbaar - doet het afzien vergeten.

Zoals ik al zei, ik ben ik niet iemand voor een lang dankwoord. Achteraf gezien is het meer een beschrijving geworden. Een beschrijving van een traject dat achteraf zo’n tien jaar heeft geduurd en waaraan veel mensen hebben bijgedragen, waarvan ik niet graag één zou vergeten. Ik wil dan ook besluiten met iedereen te bedanken die op enigerlei wijze heeft bijgedragen aan het totstandkomen van dit proefschrift. Dank jullie wel!

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About the Author

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About the Author

Jan Buitenhuis werd geboren op zaterdag 18 juli 1964 in Meppel. Na de studie Genees-kunde aan de Rijksuniversiteit Groningen ging hij in 1992 werken als onderwijscoördi-nator/docent en arts-assistent op de afdeling Chirurgie van het Academisch Ziekenhuis Groningen. In 1995 maakte hij de overstap naar de sociale geneeskunde bij de BVG (bedrijfsvereniging voor de Gezondheid, Geestelijke en Maatschappelijke belangen), het latere Cadans en begon daar met de specialisatie tot verzekeringsarts. Sinds 1998 werkt hij als medisch adviseur voor Univé Verzekeringen in Assen. Daarnaast is hij verbonden aan de afdeling Gezondheidswetenschappen, Sociale Geneeskunde van het Universitair Medisch Centrum Groningen als docent en onderzoeker. In zijn vrije tijd doet hij aan hardlopen en speelt hij akoestisch ‘fingerstyle’ gitaar

Jan Buitenhuis was born 18 July 1964 in Meppel, the Netherlands. After graduating in medicine at the University of Groningen in 1992, he worked as a lecturer and intern at the Department of Surgery of University Hospital Groningen. In 1995, he switched to social medicine and started to specialize in Insurance Medicine. In 1998 he joined Univé Insurance in Assen as a medical advisor. He also works as a lecturer and research associate for the Department of Social Medicine of University Medical Center Groningen. In his leisure time he enjoys long-distance running and playing acoustic fingerstyle guitar.

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Graduate School for Health Research SHARE

This thesis is published within the research program Public Health and Health Services Research of the Graduate School for Health Research SHARE. More information regarding the institute and its research can be obtained from our internetsite: www.rug.nl/share.

Previous dissertations from the program Public Health and Public Health Services Research

Santvoort, MM van (2009) Disability in Europe; policy, social participation and subjective well-beingSupervisor: prof dr WJA van den HeuvelCo-supervisors: dr JP van Dijk, dr LJ Middel

Stewart RE (2009) A multilevel perspective of patients and general practitionersSupervisors: prof dr B Meyboom-de Jong, prof dr TAB Snijders, prof dr FM Haaijer-Ruskamp

Jong J de (2009) The GALM effect study; changes in physical activity, health and fitness of sedentary and underactive older adults aged 55-65Supervisor: prof dr EJA Scherder Co-supervisors: dr KAPM Lemmink, dr M Stevens

Buist I (2008) The GronoRun study; incidence, risk factors, and prevention of injuries in novice and recreational runnersSupervisors: prof dr RL Diercks, prof dr W van MechelenCo-supervisor: dr KAPM Lemmink

Škodová Z (2008) Coronary heart disease from a psychosocial perspective: socioeconomic and ethnic inequalities among Slovak patientsSupervisor: prof dr SA ReijneveldCo-supervisors: dr JP van Dijk, dr I Nagyová, dr LJ Middel, dr M Studencan

Havlíková E (2008) Fatigue, mood disorders and sleep problems in patients with Parkinson’s diseaseSupervisor: prof dr JW GroothoffCo-supervisors: dr JP van Dijk, dr J Rosenberger, dr Z Gdovinová, dr LJ Middel

Bos EH (2008) Evaluation of a preventive intervention among hospital workers to reduce physical loadSupervisor: prof dr JW GroothoffCo-supervisor: dr B Krol

Wagenmakers R (2008) Physical activity after total hip arthroplastySupervisors: prof dr S Bulstra, prof dr JW GroothoffCo-supervisors: dr M Stevens, dr W Zijlstra

Zuurmond RG (2008) The bridging nail in periprosthetic fractures of the hip; incidence, biomechanics, histology and clinical outcomesSupervisor: prof dr SK BulstraCo-supervisors: dr AD Verburg, dr P Pilot

Wynia K (2008) The Multiple Sclerosis Impact Profile (MSIP), an ICF-based outcome measure for disability and disability perception in MS: development and psychometric testingSupervisors: prof dr SA Reijneveld, prof dr JHA De Keyser

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Co-supervisor: dr LJ Middel

Leeuwen RR van (2008) Towards nursing competencies in spiritual careSupervisors: prof dr D Post, prof dr H Jochemsen Co-supervisor: dr LJ Tiesinga

Vogels AGC (2008) The identification by Dutch preventive child health care of children with psychosocial problems : do short questionnaires help?Supervisors: prof dr SA Reijneveld, prof dr SP Verloove-Vanhorick

Kort NP (2007) Unicompartmental knee arthroplastySupervisor: prof dr SK BulstraCo-supervisors: dr JJAM van Raay, dr AD Verburg

Van den Akker-Scheek I (2007) Recovery after short-stay total hip and knee arthroplasty; evaluation of a support program and outcome determinationSupervisors: prof dr JW Groothoff, prof dr SK BulstraCo-supervisors: dr M Stevens, dr W Zijlstra

Van der Mei SF (2007) Social participation after kidney transplantationSupervisors: prof dr WJA van den Heuvel, prof dr JW Groothoff, prof dr PE de JongCo-supervisor: dr WJ van Son

Khan MM (2007) Health policy analysis: the case of PakistanSupervisors: prof dr WJA van den Heuvel, prof dr JW GroothoffCo-supervisor: dr JP van Dijk

Rosenberger J (2006) Perceived health status after kidney transplantationSupervisors: prof dr JW Groothoff, prof dr WJA van den HeuvelCo-supervisors: dr JP van Dijk, dr R Roland

Šléškova M (2006) Unemployment and the health of Slovak adolescentsSupervisors: prof dr SA Reijneveld, prof dr JW GroothoffCo-supervisors: dr JP van Dijk, dr A Madarasova-Geckova

Dumitrescu L (2006) Palliative care in RomaniaSupervisor: prof dr WJA van den HeuvelThe B (2006) Digital radiographic preoperative planning and postoperative monitoring of total hip replacements; techniques, validation and implementationSupervisors: prof dr RL Diercks, prof dr JR van HornCo-supervisor: dr ir N Verdonschot

Jutte PC (2006) Spinal tuberculosis, a Dutch perspective; special reference to surgerySupervisor: prof dr JR van Horn Co-supervisors: dr JH van Loenhout-Rooyackers, dr AG Veldhuizen

Leertouwer H (2006) Het heil van de gezonden zij onze hoogste wet; de geschiedenis van de medische afdeling bij de arbeidsinspectieSupervisors: prof dr JW Groothoff, prof dr MJ van Lieburg, prof dr D Post

Jansen DEMC (2006) Integrated care for intellectual disability and multilpe sclerosisSupervisors: prof dr D Post, prof dr JW GroothoffCo-supervisor: dr B Krol

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