Outcome of Mild Head Injuryand Persistent Post-concussion Syndrome

Brain Injury and Law

• Worker’s Comp Law– Worker must demonstrate injury or disability that arises out of and

during the course of employment and is accidental – Need to establish physical or mental stimulus (e.g., extreme stress)

that causes the mental injury– Sometimes hard to determine whether there was a preexisting

condition

• Tort of Emotional Distress– Relies on judicial proceedings exclusively, rather than administrative

decision-making– Case law vs. statutory law– Damages set by a jury, rather than fixed schedule

Mild TBI and Forensic NP• Mild TBI most common type of case seen by forensic NP in

personal injury setting (torts)

• Many cases of mTBI or post-concussion syndrome don’t show acute injury characteristics consistent with TBI

• mTBI refers to alteration of ongoing mental processing either due to loss of consciousness (59mins or less) or post-traumatic amnesia (not beyond 24hrs)

• For non-complicated mTBI, expect full NP recovery ~3mo post-trauma

Larrabee & Rohling, 2013

Post-concussion Syndrome• Cluster of sx including:

– memory/concentration difficulty– headache– vertigo– depression/anxiety/irritability/fatigue– blurred vision/photophobia– hyperacoustism

• Cause is controversial– Cerebral dysfunction vs. psychogenic origin– Now more commonly seen as somatoform-esque

• Incidence is unrelated to severity of injury or NP status

• Issue is lack of specificity of PCS sx bc they tend to occur in everyday life

Mitterberg et al., 1992

Post-concussion Syndrome• Mittenberg et al. (1992) asked pts with TBI & healthy controls (who

imagined they had a TBI) what symptoms they experienced/expected 6 mo following an injury

• Number of sx TBI pts reported wasn’t significantly different from what controls expected

• Headaches and visual difficulties were expected more often than they occurred

• Irritability, fatigue, and difficulty with memory occurred more often than controls expected

• However, there was a tendency of TBI to attribute premorbid sx to TBI

Mitterberg et al., 1992

Financial Incentives after Head Injury

• Controversy in the field about whether financial incentives maintain disability and symptoms after closed-head injury

• Mild head trauma w/post-concussion syndrome (PCS) has been called “compensation neurosis” that clears after settlement of litigation

Binder & Rohling, 1996

Financial Incentives after Head Injury

• Meta-analysis of financial incentives on disability, symptoms, and objective findings– Reviewed 17 articles, total of 2,353 individuals

• Found overall moderate effect size (0.47)– ^ report of abnormality and disability in patients with financial

incentives, even with less severe injuries– Monetary incentives are more powerful for mild TBI

• Findings suggest that considering secondary gain is important in an NP eval, especially for mild TBI

Binder & Rohling, 1996

So What Symptoms are Legit?

• Factors that can affect sx:– Severity of injury (e.g., length of coma,

nonreactive pupils, mass lesions, CNS complications)

– Time from injury to testing– Patient’s personal characteristics (e.g., mood,

personality)

mTBI Post-Injury Outcomes

• At one week post-trauma: domains with greatest effect size were WM, verbal and visual learning/memory

• At 93 days: only WM was significantly different from 0

Larrabee & Rohling, 2013

NP Outcomes at 1-Year Post Injury• Head injuries requiring hospitalization are associated with NP impairments at 1-

year post injury– Significant dose-response relationship– No one value or range of Impairment Index that can classify all TBI

• Impairments are shifted about 25%ile points down from GT controls

• Selective impairments in attention and memory start to emerge as head injury increases in severity– With ^ severity, most domains become affected

• More reliable differences noted on measures like Finger Tapping, PIQ, and overall NP performance, rather than attention or memory only

• Significant NP impairment due to a mild head injury is very unlikely

Dikmen et al., 1995

Should we be more stringent about test procedures to discriminate potential

psychogenic PCS vs. organically-based PCS? (e.g., should NP testing or trials for compensation only be done

after 1-year, etc.)

Dangers of Incorrectly Diagnosing Impairments

• Self-fulfilling prophecy– Patients believe they are incapable of getting

better or lack control over progress

• Potential mistreatment– Expensive or labor-intensive treatments that are

unnecessary – Unnecessary management services

Bauer, 1997

Relevance to Forensic NP

• Clinical eval of mental injury similar in torts and WC

• Aside from assessing whether there is an injury, need to understand whether it was due to work or a result of the action by the defendant; also, need to comment on prognosis

“Deadly Sins” of Forensic NP in Brain Damage Cases

(According to Dr. Bauer in 1997)1. It’s elementary

- If a test result is abnormal, must mean the person has brain damage

2. What you see is what you get- Ecological validity of NP tests

3. Two deficits are worse than one- Taking each domain as an independent sample of behavior; failing to interpret the overall pattern

4. All people are created equal- All people should fall ≥ average

“Deadly Sins” of Forensic NP in Brain Damage Cases

(According to Dr. Bauer in 1997)5. The proof is in the pudding

- If neuroradiological evidence is absent, just means NP is more sensitive

6. One man’s ceiling is another man’s floor- All NP data are subject to interpretation of the professional

7. You can use a wedge to putt from the fringe, as long as you blade it correctly- NP tests can be applied in all settings and whoever can

administer/interpret

8. If the patient complains, it must hurt- All info that the patient reports must be true

“Deadly Sins” of Forensic NP in Brain Damage Cases

(According to Dr. Bauer in 1997)9. What I don’t know won’t hurt me

- NP data and interview are enough to infer past functioning

10. It’s all in the name- You can tell what a test measures by looking at its name

11.Three words to remember: localization, localization, localization- Every test has its own special location in the brain