Anand Pandyan - The lumping and splitting of spasticity

24/09/2012

1

The lumping and splitting of spasticity

Prof Anand D Pandyan

[email protected]

Conceptual Model of

motor control

Mo

tor c

on

tro

l /

ca

pa

city

…

Me

Ma

rk

Se

nse

i

0 Twilight zone Life span (years)

Independence threshold

An illustration of motor control Control significantly improves with practice over time

Stroke is one of many adverse

events in life…

Mo

tor c

on

tro

l /

ca

pa

city

…



Stroke Increased activity

•Increased reflexes

•Spasticity

•Altered tone

•Spasm & Clonus

•Abnormal

movement patterns &

co-contraction

The paradoxical symptoms resulting from loss of activation

Reduced activity

•Weakness

•Fatigueability

•Loss of fine

motor control

24/09/2012

2

Why should one consider spasticity

as important?

Mo

tor c

on

tro

l /

ca

pa

city

…



Stroke

The Lance definition…. A motor disorder characterised by a velocity

dependent increase in the tonic stretch reflex

(muscle tone) with exaggerated tendon

reflexes, resulting from the hyper-excitability of

the stretch reflex …

The starting point for measuring spasticity

1. Resistance one feels when

stretching the joint

2. The state of readiness of the muscle

to act

What is muscle tone?

Need a measure of stiffness

Need a measure of muscle

activity

The Lance definition…. A motor disorder characterised by a velocity

dependent increase in the tonic stretch reflex

(muscle tone) with exaggerated tendon

reflexes, resulting from the hyper-excitability of

the stretch reflex...

Measuring spasticity

Measuring stiffness & muscle activity

Joint Angle

Fo

rce

to

mo

ve

lim

b

EMG

EMG

Displacement

Force/Moment

Muscle activity flexors

Muscle activity extensors

24/09/2012

3

Relationship between muscle activity and stiffness

0 20 40 60 80 100 120

10

10

20

RTPM pre treatment

RTPM post treatment

Angle (Degrees)

Fo

rce (

N)

0 20 40 60 80 100 120

20

40

60

Fast Flexor EMG pre treatment

Slow Flexor EMG pre treatment

Angle (Degrees)

EM

G (

uV

)

0 20 40 60 80 100 120

10

10

20

RTPM pre treatment

RTPM post treatment

Angle (Degrees)

Fo

rce (

N)

0 20 40 60 80 100 120

20

40

60

Fast Flexor EMG pre treatment

Slow Flexor EMG pre treatment

Angle (Degrees)

EM

G (

uV

)Slow

moveme

nt EMG

Slow

movemen

t Force

Brisk

movement

Force

Brisk

movement

EMG

Does stiffness change if muscle activity is eliminated?

20 38 56 74 92 110 128 146 164 182 200

50

20

10

40

70

100

Pre

Lin. Reg PrePost

Linear Reg Post

Angle (Degrees)

Fo

rce (

N)

RTPM pre - 1.063

RTPM post – 1.001

20 38 56 74 92 110 128 146 164 182 200

50

20

10

40

70

100

Pre

Lin. Reg PrePost

Linear Reg Post

Angle (Degrees)

Fo

rce (

N)

RTPM Pre - 0.432 (0.674)

RTPM Post - 0.155 (0.881)

Confounders (in brief) In the context of spasticity I

decided to leave the

measurement of stiffness aside and focus on the

measurement of muscle activity

So what did muscle activity look like

No Spasticity (~10%)

24/09/2012

4

Lance was correct velocity dependence existed ~ 20%

There also position dependent activity ~ 30%

The combination of course ~ 40% Two anomalies~1%

So what did muscle activity look like – very variable

Total Number of articles

Medline-314,Science direct-64 ,Web of science-309

Relevant articles – 265

Literature Review – 47 Controlled trial – 204

Total Number of articles read – 787

SCS - 14

24/09/2012

5

1. Spastic paralysis (this is a term I have seen in the literature since 1890’s)

2. The term is then used in the context of the positive symptoms in the classification developed by Hughlings Jackson

3. First form of a clinical definition produced by Denny-Brown 1960’s

4. The Lance definition of the 1980’s

Spasticity

Pa

tie

nt

clin

icia

n

The

rap

ist

Nu

rse

Ca

rer

Re

sea

rch

er

Lance Muscle

Tone

None Other

31% 35% 31% 3%

The assessment framework was no better

• Clinically the primary measure is the AS (& MAS) van Wijck et al 2001.

• The Tardieu Method is growing in popularity Haugh et al

2006.

There was a definition … but this was not an agreed

definition per se and it did not inform measurement or

clinical practice

Increased activity


•Spasticity

•Altered tone

•Spasm & Clonus

•Abnormal

movement patterns

& co-contraction

Spasticity


•Altered tone

•Spasm & Clonus

•Abnormal

movement

patterns & co-

contraction

EMG electrodes

Goniometer

Mechanism

Studying increased reflexes

sinmglKBI

L1 L2

k k

D D

m*g*l*sin(

l

2

21 LLdk

sinmglKBI

L1 L2

k k

D D

m*g*l*sin(

l

sinmglKBI

L1 L2

k k

D D

m*g*l*sin(

l

L1 L2

k k

D D

m*g*l*sin(

l

L1 L2

k k

D D

m*g*l*sin(

l

2

21 LLdk

24/09/2012

6

0 100 200 300 400 500 600 7003

2

1

0

1

2

3

Raw EMG

Rectified EMG

Smooth EMG

Raw EMG Amplitude

Time (ms)

Vo

lts (

V)

mk0

m

Quantifying reflex excitability

0 100 200 300 400 500 600 70020

15

10

5

0

5

Angle

Smooth EMG

Stretch Reflex Delay (Smooth)

Time (ms)

Deg

rees, V

mk1

mmk

3 m

Duration

Amplitude Latency

Outcome

measure

Main finding

Amplitude Greater in non-impaired subject p<0.05

Latency Latency shorter in stroke p<0.05

Rise time No difference

Duration No difference

Disordered sensori-motor control, resulting from an upper motor

neurone lesion, presenting as

intermittent or sustained involuntary activation of muscles

The lumping

• Spastic hypertonia: Velocity dependent increase in hypertonia with a catch when a threshold is exceeded. (no abnormal resting position)

• Dystonic hypertonia: After testing the limb will return to fixed resting posture that can vary with state of mind or attempted movement. (stiffness is independent of direction)

• Rigid hypertonia: Resistance to passive movement is not velocity dependent and no consistent abnormal posture is observed. (stiffness is independent of direction)

There was an attempt at splitting

(N.American Task Force) The start of the splitting - 1

Spasticity

•Increased reflexes (Not necessarily

abnormal)

•Altered tone

•Spasm

•Clonus

•Abnormal movement patterns & co-

contraction

24/09/2012

7

1. Resistance one feels when

stretching the joint

2. Readiness of the muscle to act

Altered tone

This is a confounded measure so

cannot contribute to a definition

This is reduced and is no different

to the definition of paralysis or

weakness – so there is a problem

The start of the splitting - 2 Spasticity


•Altered tone

•Spasm

•Clonus


contraction



•Altered tone

•Spasm •A transient but continuous muscular contraction

(cutaneous trigger)

•Clonus


contraction



•Altered tone

•Spasm

•Clonus •A transient rhythmic / cyclical muscle contraction

– attenuated if a stimulus is removed

(proprioceptive and/or cutaneous)

•Abnormal movement patterns & co-contraction



•Altered tone

•Spasm

•Clonus


contraction There is a need to resolve the

pathology and physiology

conundrum

The patterns of muscle activity – how do we define this?

An increase in the gain

and/or reduction in

threshold of a phasic

stretch reflex

demonstrated in a

relaxed muscle !

24/09/2012

8

Environment

Task

Individual

SP MC

SE

Spasticity as disorder control

Evidence for an epiphenomenon

Muscle

activity at

a slow

stretch

NF 1.1

(0.2)

0.97

(0.3)

0.73

(0.2)

0.74

(0.2)

0.7

(0.1)

F 1.1

(0.4)

1.1

(0.5)

1.4

(0.6)

0.82

(0.2)

1.7

(0.6)

Muscle

activity at

a fast

stretch

NF 1.2

(0.3)

1.1

(0.3)

0.9

(0.2)

0.7

(0.1)

0.8

(0.1)

F 1.0

(0.4)

1.3

(0.6)

1.3

(0.7)

1.1

(0.3)

1.9

(0.7)

W6 W0 W12 W24 W32

Time (an arbitrary non-linear scale)

Cap

acit

y (s

om

e ar

bit

rary

un

its)

Time course and muscle changes

My funders

– Action Medical Research, UK.

– N.Staffs Medical Institute, UK.

– EU

– DoH

– Biometrics Ltd, UK

– Allergan, UK

Health & Medicine

Anand Pandyan - The lumping and splitting of spasticity