The aim is to present an integrated multidisciplinary ... · Overview Four lower‐limb muscles 27...

The aim is to present an integrated multidisciplinary approach for spasticity assessment, by providing

information about accurate and valid methods that are suitable for the clinic.

An instrumented assessment of spasticity developed for routine clinical practice can assist clinicians

to make more goal directed decisions about the treatment pathways for their patients, to choose the

most efficient and cost effective management option for the individual patient and to verify the

efficacy of various procedures. Crucial in the instrumented spasticity assessment is the

multidisciplinary approach to the problem by aiming for an optimal combination of the

biomechanical, neurophysiological and clinical aspects of the problem. Three groups of signals during

standardised passive isolated movements in different lower limb joints, which are (1) stretch

characteristics (joint angle parameters), (2) reactive resistance and (3) muscle activity, are integrated

to provide objective spasticity parameters. Clinically meaningful parameters for spasticity assessment

are described and relations between biomechanical and neurophysiological characters of the reflex

responses and velocity of lengthening are highlighted. These associations between parameters, as

well as innovative parameters describing additional phenomena of spasticity, can be used to unify all

multidisciplinary knowledge in an integrated clinical spasticity assessment, illustrated by clinical

cases.

September 10, 2014 AACPDM 2014 GCMAS Symposium Desloovere Kaat

1

Outline

• Introduction

• Instrumented Spasticity Assessmento Protocolo Spasticity parameterso Angle Of Catch (AOC)o Treatment

• Advanced data-analysis for treatment fine-tuning

• Introduction



Outline

A velocity dependent increase in tonic stretch reflex (muscle tone) with exaggerated tendon jerks,

Resulting from hyper excitability of the stretch reflex,As one component of the upper motor neurone

syndrome

Lance 1980

sSpasticity definitions

3

0 1 1+ 2 3 4

Scoring the resistance felt in a specificmuscle group by passively moving a limb

at one velocity

Bohannon and Smith 1987

Clinical grading of spasticity

Modified Ashworth Scale


2

Clinical grading of spasticity

Related to muscle activity

CP Increased resistance to passive motion

Related to passive structures

E.g. Spasticity

Stiffness

Viscosity

Inertia

Outline

• Introduction



1.3Instrumented spasticity assessmentInstrumented Spasticity Assessment (ISA) Instrumented spasticity assessment


3

Reactiveresistance

Muscle length/lengthening velocity

Tonic stretch reflex

Spasticity assessment

Reactiveresistance

Tonic stretch reflex


Joint angles/velocity(muscle length/lengthening velocity)

Reactiveresistance



EMG (Tonic stretch reflex)

Torque (reactiveResistance)



EMG (Tonic stretch reflex)


4

Signals measured simultaneously

Manually performed passive stretches

Three stretch velocities

Signal integration

Electromyography (EMG)

-2 -1.5 -1 -0.5 0 0.5 1 1.5 2-0.2

-0.1

0

0.1

0.2

0.3

0.4

Time (s)

Raw

EMG (m

V)

-4 -3 -2 -1 0 1 2-20

0

20

40

60

80

100

120

140

160

Ang

lula

r ve

loci

ty (°

/s)

Time (s)

Angles and angular velocity Torque

torq

ue(N

m)

Joint angle (°)

Bar-On et al. 2013

Outline

• Introduction



Protocol: Instrumented Spasticity assessment (ISA)



Signal integration

Bar-On et al. 2013

• Manually performed passive stretches

• Three stretch velocities: • Low (5sec), Medium (1s), High (as fast as possible)

• 3 good repetitions

• 7 seconds rest between stretches

Data acquisition and sensor processing

Overview


5


OverviewMeasuring the Velocity of Stretch

Inertial Measurement Units (IMU) sensors

1. placed arbitrarily 2. joint motions/positions calibrated during measurement protocol

Gyroscope: angular velocity

Accelerometer: gravity and acceleration

Force/Torque-sensor

Interaction force therapist-patient

– 3 forces– 3 torques

Specific adaptors to attach sensor to limb.

Foot-piece:Triceps

Calf-piece:Hamstrings Knee extensors

Measuring the torque

1. Standard electrode placement (SENIAM)

2. Maximal Voluntary Contraction (MVC)

3. EMG in rest

Wireless EMG

Measuring Muscle Activity

(Hermens et. al. 2000)


6


Overview

sEMG

Motion capturingsystem

Interaction force

Clinical informationand context.

Synchronized acquisition andGrafical User Interface (GUI)

Synchronous


Acquisition set‐up


Overview

Clinical ProtocolCalibration motion sensors

• Ankle• Neutral position• Move to plantar flexion

• Knee• Full extension• Move to knee flexion

• Hip• Neutral ab/adduction• No motion


7

Calculating the net internal joint torque

Taking into account:

• Forces in non-perpendicular directions

• Moments exerted by the therapist

• Inertia

• Gravity

(Anthropometric models of Drillis 1964, and Jensen 1986)


Overview

Four lower‐limb muscles

27



Signal integration

Bar-On et al. 2013

Adductors Gastrocnemius

RectusFemoris

Hamstrings

Outline

• Introduction


• Advanced data-analysis for Treatment fine-tuning


8

Comparison between velocities

-2 -1 0 1 2 3 4 5-40

-20

0

20

Time [s]

-2 -1 0 1 2 3 4 50

50

100

150

Time [s]

-2 -1 0 1 2 3 4 50

0,02

0,04

-2 -1 0 1 2 3 4 50

10

20

Time [s]

Position

Velocityn

RMS-EMGn

Torquen

Low velocity

Time (s)


-2 -1 0 1 2 3 4 5-40

-20

0

20

Time [s]

-2 -1 0 1 2 3 4 50

50

100

150

Time [s]

-2 -1 0 1 2 3 4 50

0,02

0,04

-2 -1 0 1 2 3 4 50

10

20

Time [s]

Positionn

Velocityn

RMS-EMGn

Torquen

Time (s)

Low velocityHigh velocity


-2 -1 0 1 2 3 4 5-40

-20

0

20

Time [s]

-2 -1 0 1 2 3 4 50

50

100

150

Time [s]

-2 -1 0 1 2 3 4 50

0,02

0,04

-2 -1 0 1 2 3 4 50

10

20

Time [s]

Positionn

Velocityn

RMS-EMGn

Torquen

Time (s)


Muscle Activity

32

Raw EMG

Stretch at high velocityStretch at low velocity

Example of patient

Example of typical subject


9

Muscle Activity

Raw EMG

Stretch at high velocity

rms EMG

Muscle Activity

Start: 200 msec prior to the time of max velocityEnd: at 90% of total range of motion

Muscle Activity

• Average of EMG Area under rms EMG-time curve divided by

time and expressed as % of MVC

• Knee angle and angular velocity at EMG onset


1. Slow (ROM)

2. Medium (Ashworth-like)

3. High (Tardieu-like)

Period of interest

Change between velocities

Low Medium HighAver

aged

nor

mal

ised

rms

EMG


-2 -1 0 1 2 3 4 5-40

-20

0

20

Time [s]

-2 -1 0 1 2 3 4 50

50

100

150

Time [s]

-2 -1 0 1 2 3 4 50

0,02

0,04

-2 -1 0 1 2 3 4 50

10

20

Time [s]

Positionn

Velocityn

RMS-EMGn

Torquen

Time (s)



10

Torque at 70° knee flexion To

rque

(Nm

)

Position (°)

Low velocity

Torque

High velocity

Torque at 70° knee flexion

Torque

Torq

ue (N

m)

Position (°)

Low velocity

Torque at 70° knee flexion

Torque

Position (°)

Change between Low and High

Torq

ue(N

m)

Work

From maximum velocity until 90% of the ROM

Position (°)

Torq

ue(N

m)


11

Change between High and Low

Work

From maximum velocity until 90% of the ROM

Position (°)

Torq

ue(N

m)

Work


1. Slow (ROM)



Work


Work

43


1. Slow (ROM)



Work


Low Medium High0

1

2

3

4

5

6

7

8

Wor

k [J

]

Instrumented spasticity assessment

• Spatisticity parameters are reliable• Instrumented spasticity has discriminative validity

(between CP and TD)• Parameters can distinguish different levels of spasticity


12

Outline

• Introduction



Quantification of the spastic catch

• Subjective• Inaccurate

Haugh et al. 2006; Van de Noort 2010

Modified Tardieu Scale

Maximum change in torque (dT/dt)AOC 1

Maximum decelerationAOC 2

ISOLATED BIOMECHANICAL SIGNALSVan de Noort 2010; Wu et al. 2010

Quantitative definitions


13

Velocity dependence of the catch angle

Wu et al. 2010

The faster the stretch, the later the catch?!

We assume that the earlier the catch, the more severe the spasticityBUT

Problem with the AOC!

Angle of catch (AOC)

Joint angular position

Time (s)

Joint angular velocity

EMG

Torque

Quantification of angle of catch

-2 -1 0 1 2 3

0

1

2

3

4

5

Time [s]

Pow

er [W

]

POWER (ω*T)

-2 -1 0 1 2 3-1

0

1

2

3

4

5

6

7

Time [s]

Torq

ue [N

m]

-2 -1 0 1 2 3 4-20

0

20

40

60

80

100

120

140

160

180

Time [s]

Velo

city

[deg

/s]

TORQUE (T) VELOCITY (ω)

AOC 3 = min. (ω*T)

INTEGRATED SIGNAL

Integration of signalsQuantification of the spastic catch

Spastic Catch conclusions

The AOC depends on the velocity of stretch. AOC best defined by integrating signals. The intensity at which the catch occurs should additionally

be considered.


14

Outline

• Introduction



CP (n=31), Hamstrings muscles (n=40)

Average age 9 years

Male/female 18 male, 13 female

Paralysis injury11 unilateral involvement

20 bilateral involvement

GMFCS Range I - IV

Timing of pre-btx measurement 9 ± 15 days before

Timing of post-btx measurement 43 ± 16 days afterAssessment

Sensitivity to BTX-A treatment

Instrumented parameters pre vs. post BTXp

RMS-EMG (mV) *<0.001

Torque at 70˚ (Nm) *<0.001

Torque at VMAX (Nm) *0.009

Work (J) *<0.001

AOC (%) *<0.001

AOC power (W) *<0.001

Spasticity parameters are sensitive to the effect of BTX

Sensitivity to BTX-A treatment2.3

ElineBTX dosage

Pre Ashworth

Post Ashworth

PreTardieu

PostTardieu

GAS 3U/Kg 1+ 1+ -15° -15°

MEH 4U/Kg 1+ 1+ -50° -50°

Yana

GAS 3U/Kg 1+ 1+ -15° -10°MEH 1U/Kg 1+ 1+ -50° -70°

Clinical cases: Eline and YanaBTX‐dosage and clinical results


15

Instrumented spasticity assessmentEffect of botulinum toxin

• Spatisticity parameters are sensitive in measuring the effect of BTX-A in the hamstrings

• Instrumented spasticity is more responsive than clinical scales

• Torque is less sensitive to BTX than EMG

Outline

• Introduction



How can we explain the variation in response to treatment?

• Advanced analysis of EMG

• Advanced analysis of torqueTime (s)

SLOW stretch

RMS‐EM

G (mV)

RMS‐EM

G (mV) FAST stretch

Time (s)

Gastrocnemius

Advanced analysis of EMG


16

Time (s)

RMS‐EM

G (mV)

RMS‐EM

G (mV)

Time (s)

Gastrocnemius

RMS‐EM

G (mV)

RMS‐EM

G (mV)

Time (s)Time (s)

Hamstrings

EMG

SLOW stretch FAST stretch

SLOW stretch FAST stretch

EMG

-4 -2 0 2 4 6 8 10-40

-30

-20

-10

0

10

20

30

Time [s]

Posi

tion

[deg

]

90% ROM

63.33% ROM

36.66% ROM

10% ROM

Position zones

P1 P2 P3

12

3

1

2

3

0

5

10

Fast stretch

Slow stretch

More muscle length

Aver

age

norm

aliz

ed

RM

S-EM

G (%

)

More muscle lengthening velocity

Medium stretch

Average normalized RMS-EMG

Position zones

More muscleactivation

12

3

1

2

3

0

20

40

60

80

velocity categories

zones

Avg

. nor

m. r

ms

emg

med

. ham

. [%

]

Low velocity dependent1

23

1

2

3

0

5

10

15

20

velocity categories

zones

Avg

. nor

m. r

ms

emg

med

. ham

. [%

]

Mixed pattern

Visual classification of EMG patterns

Study Results (N = 54 children with CP)

12

3

1

2

3

0

5

10

Mixed more velocity Mixed more low velocity dependent

Velocity dependent1

23

1

2

3

0

1

2

3

4

5

Gastrocnemius

Rectus Femoris

Adductors

Medial Hamstrings


17

12

3

1

2

3

0

5

10

Parameter development

EMG parameters

Fast stretch

Slow stretch

Aver

age

norm

aliz

ed

RM

S-EM

G (%

)

Medium stretch

Position zones

Study Results

Normalized RMS-EMG (%)

Nor

mal

ized

RM

S-E

MG

(%)

Pilot studySpastic hamstring muscles (n=9)

Botulinum Toxin-A

Normalized RMS-EMG (%)

Nor

mal

ized

RM

S-E

MG

(%)

Study Results

More position dependent

More velocity dependent

Pilot study

Conclusions

• Differences between musclesHamstrings and adductors => low velocity-dependentGastrocnemius and Rectus femoris => velocity dependent

• Differences between patients

Pattern definition may help to fine-tune patient specific treatment

Bar-On 2013, 2014


18

Advanced analysis of torque

Is it stiff or is it spastic?

Stiff SpasticASSESS

?Neural causes

Hyper-active stretch reflexNon-neural causes

Muscle and joint structure

Stiffness

Viscosity

Muscle activation

Inertia

Increased joint torque

Alibiglou et al. 2008Harlaar et al. 2000 De Vlugt et al. 2012

Computational models and motor-driven systems

Motor-driven systems

Stiff or Spastic?

Related to passive structures

Stiffness

Viscosity

Inertia

Torque decomposition

Anthropometric parameters

measured and estimated

(Drillis 1964 and Jensen 1986)

torque(Nm

)

Joint angle (°)

(De Vlugt et al. 2010)

1

EMG (mV)

Time(s)


19

-30 -20 -10 0 10 20 30 40

0

2

4

6

8

Non-neural

Stiffness

Viscosity

Inertia




Joint angle (°)

torq

ue(N

m)

-30 -20 -10 0 10 20 30 40

0

2

4

6

8

torq

ue(N

m)

Joint angle (°)

SLOW stretch

Resulting torque

(De Vlugt et al. 2010)

-2 -1.5 -1 -0.5 0 0.5 1 1.5 2-0.2

-0.1

0

0.1

0.2

0.3

0.4

-30 -20 -10 0 10 20 30 40

0

2

44

6

8

Joint angle (°)

torq

ue(N

m)

Time (s)

EMG

(mv)

Time (s)

-30 -20 -10 0 10 20 30 40

0

2

44

6

8

-30 -20 -10 0 10 20 30 40

0

2

44

6

8

-30 -20 -10 0 10 20 30 40

0

2

4

6

8

torq

ue(N

m)

Joint angle (°)-30 -20 -10 0 10 20 30 40

0

2

4

6

8

Non-neural

Stiffness

Viscosity

Inertia




Joint angle (°)

torq

ue(N

m)

Joint angle (°)

torq

ue(N

m)

Joint angle (°)

torq

ue(N

m)

FAST stretch

SLOW stretch

Resulting torque

-2 -1.5 -1 -0.5 0 0.5 1 1.5 2-0.2

-0.1

0

0.1

0.2

0.3

0.4

-30 -20 -10 0 10 20 30 40

0

2

44

6

8

-30 -20 -10 0 10 20 30 40

0

2

44

6

8

-30 -20 -10 0 10 20 30 40

0

2

4

6

8

torq

ue(N

m)

Joint angle (°)-30 -20 -10 0 10 20 30 40

0

2

4

6

8

Non-neural

Stiffness

Viscosity

Inertia




Joint angle (°)

torq

ue(N

m)

Joint angle (°)

torq

ue(N

m)

Joint angle (°)

torq

ue(N

m)

FAST stretch

SLOW stretch

Resulting torque

-2 -1.5 -1 -0.5 0 0.5 1 1.5 2-0.2

-0.1

0

0.1

0.2

0.3

0.4

What part in the curve is not explained by stiffness or viscosity?

Neural

Muscle activationMuscle

activation

Fitting error

= 0.44 Nm

-30 -20 -10 0 10 20 30 40

0

2

4

6

8

joint position [deg]

mom

ent [

Nm

]

-30 -20 -10 0 10 20 30 40

0

2

4

6

8


mom

ent [

Nm

]

-30 -20 -10 0 10 20 30 40-2

0

2

4

6

8

10


mom

ent [

Nm

]

-30 -20 -10 0 10 20 30 40-2

0

2

4

6

8

10


mom

ent [

Nm

]

Joint angle (°)

Torq

ue (N

m)

Joint angle (°)

Torq

ue (N

m) SLOW stretchFAST stretch

Model deviation

Fitting error

= 0.04 NmModel deviation

Slow stretch is well explained by stiffness curve

Large deviation from stiffness during fast stretch

>

Searching for maximum fitting error

Deviation from the model


20

-30 -20 -10 0 10 20 30 400

0.005

0.01

0.015

0.02

0.025

0.03

Joint position [deg]

RM

S-EM

G (m

V)

-30 -20 -10 0 10 20 30 40-2

0

2

4

6

8

10


mom

ent [

Nm

]

-30 -20 -10 0 10 20 30 40-2

0

2

4

6

8

10


mom

ent [

Nm

]

Joint angle (°)

Torq

ue (N

m)

Joint angle (°)

RM

S-E

MG

(mV

)

NeuralNon-neural

Stiffness

Viscosity

InertiaMuscle

activation

FAST stretch

Muscle activation

Processed EMG

Deviation from the model and EMG onset

-30 -20 -10 0 10 20 30 40-2

0

2

4

6

8

10

-30 -20 -10 0 10 20 30 40-2

0

2

4

6

8

10


mom

ent [

Nm

]

Non-neural

Stiffness

Viscosity

InertiaNeural

Muscle activation

Non-neural

Stiffness

Viscosity

InertiaNeural

Muscle activation

Joint angle (°)

Torq

ue (N

m)

0.44 Nm

Bar-On 2014

Joint angle (°)

Torq

ue (N

m)

-30 -20 -10 0 10 20 30 40-2

0

2

4

6

8

10

Joint angle (°)

Torq

ue (N

m)

1.99 J

Work

VComparison of parameters

Model deviation

CP TD p-value

Model Deviation (Nm) 2.70 (1.06) 0.90 (0.63) <0.001*

Work deviation (J) 2.07 (1.06) 0.53 (0.33) <0.001*Work (J) 2.99 (1.29) 1.21 (0.55) <0.001*

ICC SEM MDC

Model Deviation (Nm) 0.96 0.36 0.84

Work deviation (J) 0.96 0.31 0.72Work (J) 0.97 0.35 0.82

Results

Reliability

Discriminate validity

Pre-BTX Post-BTX p-value

Model Deviation (Nm) 2.74 (1.01) 1.80 (0.80) 0.006*

Work deviation (J) 2.02 (0.86) 0.53 (0.33) 0.012*Work (J) 3.17 (1.46) 2.67 (1.53) 0.183

Sensitivity

Conclusions

• Neural component of torque is sensitive to treatment

• Non-neural component of torque is not sensitive to treatment

Torque decomposition may help to fine-tune patient specific treatment


References

Bar‐On, L., Aertbeliën, E., Molenaers, G., Desloovere, K. (2014). Muscle activation patterns when passively stretching spastic lower limb muscles of children with cerebral palsy. PLoS One, art.nr. doi:10.1371/journal.pone.0091759.

Bar‐On, L., Aertbeliën, E., Molenaers, G., Desloovere, K. (2014). Manually controlled instrumented spasticity assessments: a systematic review of psychometric properties. Developmental Medicine and Child Neurology, art.nr. DOI: 10.1111/dmcn.12419.

Bar‐On, L., Van Campenhout, A., Desloovere, K., Aertbeliën, E., Huenaerts, C., Vandendoorent, B., Nieuwenhuys, A., Molenaers, G. (2014). Is an instrumented spasticity assessment an improvement over clinical spasticity scales in assessing and predicting the response to integrated Botulinum Toxin‐A treatment in children with Cerebral Palsy?. Archives of Physical Medicine and Rehabilitation, 95 (3), 515‐523.

Bar‐On, L., Aertbeliën, E., Molenaers, G., Van Campenhout, A., Vandendoorent, B., Nieuwenhuys, A., Jaspers, E., Hunaerts, C., Desloovere, K. (2014). Instrumented assessment of the effect of Botulinum Toxin‐A in the medial hamstrings in children with cerebral palsy. Gait & posture, 39 (1), 17‐22.

Bar‐On, L., Desloovere, K., Molenaers, G., Harlaar, J., Thalia, K., Aertbeliën, E. (2014). Identification of the neural component of torque during manually‐applied spasticity assessments in children with cerebral palsy. Gait & Posture.

Bar‐On, L., Aertbeliën, E., Molenaers, G., Bruyninckx, H., Monari, D., Jaspers, E., Cazaerck, A., Desloovere, K. (2013). Comprehensive quantification of the spastic catch in children with Cerebral Palsy. Research in Developmental Disabilities, 34 (1), 386‐396.

Desloovere, K., Bar‐On, L. (2013). Challenges of instrumented spasticity assessment. Developmental Medicine and Child Neurology, 55 (7), art.nr. 10.1111/dmcn.12141, 586‐7.

Bar‐On, L., Aertbeliën, E., Wambacq, H., Severijns, D., Bernard, D., Bruyninckx, H., Jaspers, E., Lambrecht, K., Huenaerts, C., Janssens, L., Van Gestel, L., Molenaers, G., Desloovere, K. (2013). A Clinical Measurement to Quantify Spasticity in Children with Cerebral Palsy by Integration of Multidimensional Signals. Gait & Posture, 38, 141‐147.

Bohannon RW, Smith MB. Interrater reliability of a modified Ashworth scale of muscle spasticity. Phys Ther 1987; 67: 206–7. De Vlugt E, de Groot JH, Schenkeveld KE, Arendzen JH, van der Helm FCT, Meskers CGM. The relation between neuromechanical parameters and Ashworth score in stroke patients. J Neuroeng Rehabil 2010;7:35.Drillis Haugh AB, Pandyan AD, Johnson GR. A systematic review of the Tardieu Scale for the measurement of spasticity. Disabil Rehabil 2006; 28: 899–907. Jensen RK. Body segment mass, radius and gyration proportions of children. Journal of Biomechanics 1986;19:359–68. Lance, J. W. (1980). Pathophysiology of spasticity and clinical experience with baclofen. In R. G. Feldman, R. R.Young, & W. P. Koella (Eds.), Spasticity: Disordered motor control. Chicago: Yearbook Medical. van den Noort, J. C., Scholtes, V. A., Becher, J. G., & Harlaar, J. (2010). Evaluation of the catch in spasticity assessment in children with cerebral palsy. Archives of Physical Medicine and Rehabilitation, 91, 615–623. Wu, Y. N., Ren, Y. P., Goldsmith, A., Gaebler, D., Liu, S. Q., & Zhang, L. Q. (2010). Characterization of spasticity in cerebral palsy: Dependence of catch angle on velocity. Developmental Medicine and Child Neurology, 52, 563–569.


The aim is to present an integrated multidisciplinary ... · Overview Four lower‐limb muscles 27...

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