Soleus stretch reflex in subjects with cerebrovascular accident

Abstract

Aims The conclusion that circumferential pressure decreases reflex activity in subjects with neuromuscular disorders including cerebrovascular accidents has recently come under scrutiny due to the methods used to analyze its effects. Thus far, studies used to determine circumferential pressure's efficacy on motor neuron reflex excitability have mainly used the H-reflex technique on resting muscle. The purpose of this study was to investigate the effect that circumferential pressure has on the soleus stretch reflex (SSR) when superimposed onto a voluntary ramp movement in patients with cerebrovascular accident (CVA). Methods Thirteen patients with CVA volunteered for this study. SSR's were investigated before, during and after the application of pressure to the calf. Twenty-five SSR's were recorded and averaged for each experimental phase. Peak to peak amplitudes were measured and then normalized for comparisons. Reflex latencies were also measured. Friedman Repeated Measures Analysis of Variance on Ranks were used to analyze the differences in SSR latency and amplitude from baseline values. Findings Patients with CVA showed a decrease of 35% (P<0.006) in SSR mean amplitude. Postpressure values and latencies were not significantly different from baseline values. Conclusions The results show circumferential pressure has an inhibitory effect on spinal cord muscular reflexes for patients with CVA and may be used as a supplement to other treatments in temporarily reducing spinal cord reflex related muscle activity associated with a neurological dysfunction