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 1890s) 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 1960s Tone 31% 35% 31% 3% 4. The Lance definition of the 1980s 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(縁 I縁 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