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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
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
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
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
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
24/09/2012




                           Quantifying reflex excitability
                                              Raw EMG Amplitude            mk0  m                                                   Stretch Reflex Delay (Smooth)                       Outcome              Main finding
                                        Amplitude
                3
                                                                                                             5

                2
                                                                                                                              mk1  m mk3  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
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
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

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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 mk0  m Stretch Reflex Delay (Smooth) Outcome Main finding Amplitude 3 5 2 mk1  m mk3  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