Anand Pandyan - The lumping and splitting of spasticity
1. 24/09/2012
Conceptual Model of
motor control
Sensei
Motor control / capacity …
The lumping and splitting of
spasticity
Mark
Prof Anand D Pandyan
Independence
a.d.pandyan@keele.ac.uk
Me
threshold
0 Twilight zone
Life span (years)
An illustration of motor control Control significantly improves with
practice over time
Stroke is one of many adverse The paradoxical symptoms resulting
events in life… from loss of activation
Motor control / capacity …
Stroke Increased activity Reduced activity
•Increased reflexes •Weakness
•Spasticity •Fatigueability
•Altered tone •Loss of fine
•Spasm & Clonus motor control
Independence
threshold
•Abnormal
movement patterns &
0 Twilight zone co-contraction
Life span (years)
1
2. 24/09/2012
Why should one consider spasticity The starting point for measuring
as important?
spasticity
Motor control / capacity …
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
Independence
threshold
the stretch reflex …
0 Twilight zone
Life span (years)
What is muscle tone? Measuring spasticity
1. Resistance one feels when The Lance definition….
stretching the joint A motor disorder characterised by a velocity
Need a measure of stiffness dependent increase in the tonic stretch reflex
(muscle tone) with exaggerated tendon
reflexes, resulting from the hyper-excitability of
the stretch reflex...
2. The state of readiness of the muscle
to act Need a measure of muscle
activity
Measuring stiffness & muscle activity
Displacement
Force to move limb
EMG
M uscle activity extensors Force/M oment
Muscle activity flexors
EMG
Joint Angle
2
3. 24/09/2012
Does stiffness change if muscle
Relationship between muscle
activity is eliminated?
activity and stiffness
100 RTPM Pre - 0.432 (0.674) 100 RTPM pre - 1.063
20 Brisk
movement
60 Brisk
movement 70 RTPM Post - 0.155 (0.881)70 RTPM post – 1.001
Force Slow EMG Slow
Force (N)
Force (N )
40 40
EMG (uV)
10 40 moveme
Force (N)
movemen
t Force nt EMG 10 10
20 20 38 56 74 92 110 128 146 164 182 200 20 38 56 74 92 110 128 146 164 182 200
0 20 40 60 80 100 120 20 20
50 50
10
0 20 40 60 80 100 120
Angle (Degrees) Angle (Degrees)
Angle (Degrees) Angle (Degrees) Pre Pre
RTPM pre treatment Fast Flexor EMG pre treatment
Lin. Reg Pre Lin. Reg Pre
RTPM post treatment Slow Flexor EMG pre treatment Post Post
Linear Reg Post Linear Reg Post
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
No Spasticity (~10%)
So what did muscle activity
look like
3
4. 24/09/2012
Lance was correct velocity There also position dependent
dependence existed ~ 20% activity ~ 30%
The combination of course ~ 40% Two anomalies~1%
Total Number of articles
Medline-314,Science direct-64 ,Web of science-309
So what did muscle activity
look like – very variable Total Number of articles read – 787
Relevant articles – 265
Literature Review – 47 Controlled trial – 204
SCS - 14
4
5. 24/09/2012
1. Spastic paralysis (this is a term I have
seen in the literature since 1890’s) Spasticity
2. The term is then used in the context of
Researcher
clinician
the positive symptoms in the
Patient
Nurse
Therapist
Carer
classification developed by Hughlings
Jackson
3. First form of a clinical definition Lance Muscle None Other
produced by Denny-Brown 1960’s
Tone
31% 35% 31% 3%
4. The Lance definition of the 1980’s
The assessment framework was
no better There was a definition …
• Clinically the
primary measure but this was not an agreed
is the AS (& MAS)
v an Wijck et al 2001. definition per se and it did not
inform measurement or
• The Tardieu
Method is clinical practice
growing in
popularity Haugh et al
2006.
Studying increased reflexes
Increased activity Spasticity
Mechanism
•Increased reflexes •Increased reflexes
•Spasticity •Altered tone
•Altered tone •Spasm & Clonus L1 L2 L1
k d L2
2
•Spasm & Clonus •Abnormal k k
•Abnormal movement EMG
movement patterns patterns & co- electrodes
& co-contraction contraction Goniometer l
D D
m*g*l*sin(
I B K mgl sin
5
6. 24/09/2012
Quantifying reflex excitability
Raw EMG Amplitude mk0 m Stretch Reflex Delay (Smooth) Outcome Main finding
Amplitude
3
5
2
mk1 m mk3 m Latency measure
0
Amplitude Greater in non-impaired subject p<0.05
1
Degree s, V
5
Volts (V)
0
Latency Latency shorter in stroke p<0.05
10
1
2 15
Rise time No difference
Duration
3 20
0 100 200 300
Time (ms)
400 500 600 700 0 100 200 300 400 500 600 700 Duration No difference
Time (ms)
Raw EMG
Rectified EMG Angle
Smooth EMG Smooth EMG
The lumping
Disordered sensori-motor control,
resulting from an upper motor
neurone lesion, presenting as
intermittent or sustained
involuntary activation of muscles
There was an attempt at splitting The start of the splitting - 1
(N.American Task Force) Spasticity
• Spastic hypertonia: Velocity dependent •Increased reflexes (Not necessarily
increase in hypertonia with a catch when abnormal)
a threshold is exceeded. (no abnormal •Altered tone
resting position) •Spasm
• Dystonic hypertonia: After testing the limb will return to fixed resting
posture that can vary with state of mind or attempted movement.
•Clonus
(stiffness is independent of direction) •Abnormal movement patterns & co-
• Rigid hypertonia: Resistance to passive movement is not velocity
dependent and no consistent abnormal posture is observed. contraction
(stiffness is independent of direction)
6
7. 24/09/2012
Altered tone The start of the splitting - 2
Spasticity
1. Resistance one feels when •Increased reflexes
stretching the joint •Altered tone
This is a confounded measure so •Spasm
cannot contribute to a definition
•Clonus
•Abnormal movement patterns & co-
2. Readiness of the muscle to act contraction
This is reduced and is no different
to the definition of paralysis or
weakness – so there is a problem
The start of the splitting - 3 The start of the splitting - 4
Spasticity Spasticity
•Increased reflexes •Increased reflexes
•Altered tone •Altered tone
•Spasm •Spasm
•A transient but continuous muscular contraction •Clonus
(cutaneous trigger) •A transient rhythmic / cyclical muscle contraction
•Clonus – attenuated if a stimulus is removed
•Abnormal movement patterns & co- (proprioceptive and/or cutaneous)
contraction •Abnormal movement patterns & co-
contraction
The start of the splitting - 5 The patterns of muscle activity –
Spasticity how do we define this?
•Increased reflexes An increase in the gain
•Altered tone and/or reduction in
•Spasm threshold of a phasic
•Clonus stretch reflex
•Abnormal movement patterns & co- demonstrated in a
contraction There is a need to resolve the relaxed muscle !
pathology and physiology
conundrum
7
8. 24/09/2012
Environment
SE
Evidence for an epiphenomenon
W0 W6 W12 W24 W32
Individual Muscle NF 1.1 0.97 0.73 0.74 0.7
activity at (0.2) (0.3) (0.2) (0.2) (0.1)
MC SP a slow F 1.1 1.1 1.4 0.82 1.7
stretch (0.4) (0.5) (0.6) (0.2) (0.6)
Task
Muscle NF 1.2 1.1 0.9 0.7 0.8
activity at (0.3) (0.3) (0.2) (0.1) (0.1)
a fast F 1.0 1.3 1.3 1.1 1.9
stretch (0.4) (0.6) (0.7) (0.3) (0.7)
Spasticity as disorder control
Capacity (some arbitrary units)
My funders
– Action Medical Research, UK.
– N.Staffs Medical Institute, UK.
– EU
– DoH
– Biometrics Ltd, UK
– Allergan, UK
Time (an arbitrary non-linear scale)
Time course and muscle changes
8