Spasticity in spinal cord injured patients: 1. Short-term effects of surface electrical stimulation

Twelve spinal cord injured subjects participated in a study of the short-term effects on leg spasticity of electrical stimulation of the quadriceps. Spasticity was quantified through the use of a normalized relaxation index (R2n) obtained from the pendulum drop test both before and after measurement of isometric quadriceps torque in response to 20 minutes of cyclic electrical stimulation. Two or three baseline evaluations were made on each subject, tests being at least one day apart. By comparing the first prestimulus baseline assessment of spasticity with that obtained poststimulus, we obtained a measure of changes in spasticity brought about by fatiguing exercise. We found that spasticity significantly (p less than or equal to 0.005) decreased after stimulation. To investigate whether this change was due to electrical stimulation or was a function of the performance of the drop test itself (ie, passive range of motion of the knees), drop-to-drop variability during the pendulum drop test both before and after stimulation was assessed. A comparison was made of the R2n value of the last drop before stimulation to that of the first drop afterward, to assess the direct effect of stimulation on spasticity. Spasticity decreased significantly (p less than or equal to 0.05) during the leg ranging inherent in the drop test itself, particularly for subjects with shorter times postinjury. Spasticity also decreased significantly as a direct result of electrical stimulation. This latter change could be accounted for by an interaction of peak quadriceps torque and the initial measure of spasticity before stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)