Quantitative assessment of intrathecally administered baclofen in spasticity.
OBJECTIVE
To quantitatively assess the antispastic effect of intrathecally administered baclofen on muscle stiffness in spastic patients.


METHODS
Case-control study.


METHODS
Clinical laboratory in a university hospital of a city of more than 1,000,000 inhabitants.


METHODS
Eighteen healthy adult volunteers (9 men, 9 women) were recruited for establishing the normal values. Eleven spastic patients (8 men, 3 women) comprised the study group.


METHODS
The resistance to passive sinusoidal displacement of 5 degrees imposed to the ankle joint was measured at frequencies from 3 to 12 Hz. Torque and displacement signals were subjected to a Fourier analysis to isolate the elastic and viscous components of the total muscle stiffness.


RESULTS
In comparison with the period before intrathecal injection, and with the control group, it was shown that at 4 hours after injection, stretch reflex activity was abolished and elastic and viscous muscle stiffness approached control values. The abnormal residual stiffness concerned only the elastic component due to chronic transformations of the spastic muscle and/or due to changes in joints and periarticular connective tissue. This antispastic effect was completely reversed 36 hours after injection.


CONCLUSIONS
The present study shows that the antispastic effect of intrathecally administered baclofen in spastic patients can be quantitatively assessed by a sensitive method allowing measurement of elastic and viscous components of muscle stiffness.
Detrembleur
C
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Unité de Réadaptation, Université Catholique de Louvain, Brussels, Belgium.
Plaghki
L
L
D000328:Adult; D000843:Ankle Joint / Q000503:physiopathology; D001418:Baclofen / Q000008:administration & dosage*; D016022:Case-Control Studies; D004576:Electromyography; D005260:Female; D006801:Humans; D007278:Injections, Spinal; D008297:Male; D008875:Middle Aged; D009125:Muscle Relaxants, Central / Q000008:administration & dosage*; D009128:Muscle Spasticity / Q000188:drug therapy*; D016896:Treatment Outcome
D009125:Muscle Relaxants, Central; D001418:Baclofen