The Effect of Paired Muscle Stimulation on Preparation for Movement

ABSTRACTPaired muscle stimulation is used clinically to facilitate the performance of motor tasks for individuals with motor dysfunction. However, the optimal temporal relationship between stimuli for enhancing movement remains unknown. We hypothesized that synchronous, muscle stimulation would increase the extent to which stimulated muscles are concurrently prepared for movement. We validated a measure of muscle-specific changes in corticomotor excitability prior to movement. We used this measure to examine the preparation of the first dorsal interosseous (FDI), abductor digiti minimi (ADM), abductor pollicis brevis (APB) muscles prior to voluntary muscle contractions before and after paired muscle stimulation at four interstimulus intervals (0, 5, 10, and 75 ms). Paired muscle stimulation increased premovement excitability in the stimulated FDI, but not in the ADM muscle. Interstimulus interval was not a significant factor in determining efficacy of the protocol. Paired stimulation, therefore, did not r...