Center for Rett syndrom Kvantitativ spastictets-evaluering Neurologisk faggruppe - Generalforsamling 2011 Forskning i Neurologisk Fysioterapi 29. oktober 2011 Fysioterapeut, cand.scient.san., PhD Jakob Lorentzen
Agenda Hvad er spasticitet? Pathofysiologisk / klinisk Hvordan kan spasticitet evalueres kvantitativt (elektrofysiologisk og biomekanisk) Er disse parametre relaterede til de kliniske evalueringsmetoder? Stivhed efter læsion eller sygdomme I CNS stammer fra forskellige patofysiologiske mekanismer og kan vi påvirke disse?
Spasticitet Hvad er det for noget? 1822-7 A spasticity or want of pliancy in the muscular fibres. (http://www.oed.com/) Lat. Spasticus; Pull towards yourself (http://zeus.atilf.fr/tlf.htm)
Elementer som bidrager til forøget tonus
Definition på spasticitet Spasticity is a motor disorder characterized by a velocitydependent increase in tonic stretch reflexes ( muscle tone ) with exaggerated tendon jerks, resulting from hyperexcitability of the stretch reflex, as one component of the upper motor neuron syndrome. Lance 1980
Monosynaptisk refleks
Spinale adaptationer over tid Spasticity is a motor disorder characterized by a velocitydependent increase in tonic stretch reflexes ( muscle tone ) with exaggerated tendon jerks, resulting from hyperexcitability of the stretch reflex, as one component of the upper motor neuron syndrome. Lance 1980
Forskellige mekanismer I rygmarven er indvolveret I reguleringen af stræk refleksen Post-activation depression I følge litteraturen er der ikke god overensstemmelse mellem kliniske test og presynapktisk inhibition og reciprok inhibition Post-aktiverings depression?
Post-aktiverings depression decreased probability of transmitter release from the synapses.
Post-aktiverings depression
Har Post-aktiverings depression nogen indflydelse på den mekaniske manifestation af spasticitet? 6 5 4 Torque Nm 3 2 1 0 0 50 100 150 200 250 Stretch velocity deg/s
Resultater Post-aktiverings depression Stræk evokeret torque Postactivation depression of reflex Torque (size of reflex torque at 1 s as % of reflex torque at 15 s) Grey et al., 2008
Post-aktiverings depression bidrager til tonus den samlede tonus Dette forklarer måske hvorfor der ikke er god overensstemmelse mellem Post-aktiverings depression og AS!
Andre faktorer end Post-aktiverings depression bidrager til forøgede reflekser Andre faktorer end forøgede reflekser bidrager til forøget tonus Kliniske spasticitetsevalueringssystemer er måske ikke sensitive nok til at identificere små ændringer Men, hvad er det egentlig vi mærker I klinikken?
Patienter har ofte forskellige symptomer Forøget muskel tonus Hyperexcitable strækreflekser Forøgede flexor reflexer Spasmer Babinski Dystoni Kontrakturer? disordered sensi-motor control, resulting from an upper motor neuron lesion, presenting as intermittent or sustained involuntary activation of muscles Kilde: Pandyan et al. Spasticity, clinical perceptions and neurological realities and meaningful measurements. Disabil Rehabil 2005;27:2-6.
Features contributing to muscle tone Der er et problem med definitioner! Malhotra and Pandyan, 2009
Term Tone Hypertonia Spasticity Hyperreflexia Dystonia Active stiffness Passive Stiffness Definition The resistance felt when moving a limb passively through range due to inertia and the compliance of the tissues. A greater than normal resistance felt when moving a limb passively through range. A motor disorder charactericed by a velocity-dependend increase in tonic stretch reflexes (muscle tone) with exaggerated tendon jerks, resulting from hyperreflaxia of the stretch reflex as one component of the upper motor neurone syndrome (Lance, 1980) A greater than normal reflex response (e.g. the presence of reflex response when a relaxed muscle is stretched at the speed of normal movements). A movement disorder in which involuntary sustained or intermittent muscle contractions cause twisting and repetitive movements, abnormal postures or both (Sanger et al., 2003) The force required to lengthen a muscle, which is active (i.e. the slope of the active force-displacement curve). The force required to lengthen a muscle at rest (i.e. the slope of the force-displacement curve). Kilde: Descriptions of terms (from Barnes, 2008)
Hypertoni Årsager til hypertoni Active stiffness Passive stiffness (Contracture)
Hypertoni Afferent (disinhibited spinal reflexes) Corticospinal Rubrospinal Årsager til hypertoni Active stiffness Passive stiffness (Contracture) Vestibulospinal/tectospinal/ reticulospinal Efferent (tonic supraspinal drive) Arthrogenetic changes Myogenetic changes Ib afferent Mn Ia afferent Gr. II afferent Renshaw inhibition Ib inhibition Reciprocal inhibition Muscle
Afferent (disinhibited spinal reflexes) Proprioceptive reflexes Factors causing hypertonicity Active stiffness Passive stiffness (Contracture) Cutaneous and nociceptive reflexes Efferent (tonic supraspinal drive) (Spastic) dystonia Men hvad er klinisk relevant? Arthrogenetic changes Intra-articular adhesion formation Myogenetic changes Loss of sacromers in series
Kan aktiv- og passiv stivhed adskilles I klinikken?
Metode Klinisk metode Objektiv biomekanisk metode
Methods Normalization 17 stretch velocities 7 6 5 Torque (Nm) 4 3 2 1 0 50 100 150 200 250 Stretch velocity deg/s.
Methods - destinction between active and passive stiffness
Ischemia
Ischemia
Material Controls Persons clinically identified with spasticity Ashworth >1 (Ashworth = 0) Healthy MS Stroke Sci 31 9 ( 21) 10 12 ( 4)
Increase in reflex size for spastic persons Reflex EMG Reflex torque
Results 60 B Passiv stivhed P=0.139 Refleks stivhed Passive stifness (% of Mmax) 50 40 30 20 10 0 Healthy MS Stroke SCI All pt Lorentzen et al., 2010
Kan vi identificere forøget refleks aktivitet (spasticitet)? Refleks raske / patienter Refleks / Ashworth Lorentzen et al., 2010
Kan vi forbedre måden hvormed vi måler spasticiet klinisk med alternative metoder?
Resultater Hånd holdt / stationært dynamometer Interrater reliabilitet Unpublished data
Resultater Raske / Spastiske Konklusion Metoden kan muligvis anvendes I klinikken Unpublished data
Hvordan kan vi så behandle hypertoni? el
Baggrund ND The lack of mobility of the peripheral nerves in relation to the surrounding structures (so called mechanical stresses ) is suggested (Shacklock, 1995) to be caused by variations in blood flow, axonal transport and impulse traffic. The primary treatment objective for ND is thus to restore the natural movement of the neural tissue and surrounding mechanical tissue and thereby reduce the intrinsic pressure on the neural tissue to regain natural physiological function (Butler, 2000; Shacklock, 1995).
Ofte anvendt behandlingsform i fysioterapi. MEN ingen evidens for effekten. Ellis 2008, The Journal of Manual & Manipulative Therapy
Objektiv målt stivhed i knæleddet
ROM (R1 og R2)
Subjektiv vurderet tonus reduktion
MAS - blindet
Opsamling Post-aktiverings depression manifesterer sig biomekanisk Udviklet metode som adskiller aktiv- og passiv stivhed Klinisk adskillelse mellem aktiv- og passiv stivhed er meget vanskelig Vi fandt ikke nogen stivhedsreduktion efter ND behandlinger Ny objektiv metode til måling af stivhed som kan anvendes I klinikken
Tak for jeres opmærksomhed jlorentzen@ifi.ku.dk Center for Rett syndrom
Results Reflex stiffness * * * * * * Reflex stiffness (normalized) * * * * * * Lorentzen et al., 2010
Hvorfra stammer begrebet? 1840 Marshall Hall - muscle activity independent of control by cortex. 1863 Sechenov loss of cerebral inhibition to account for the hightened reflexes. 1880 Brissaud differentiated between muscle activity and contracture. 1886 Gowers emphasized the increase of tendon reflexes associated with spasticity 1906 Sherrington decription muscle tone whenever the term was used.