| Summary: | 碩士 === 長庚大學 === 復健科學研究所 === 92 === Somatosensory input was required for accurate motor performance and for new motor skill learning. In humans, above motor threshold peripheral nerve stimulation resulted in an increased excitability of the motor pathway to the stimulated body parts. The purpose of this study was to investigate whether peripheral sensory afferents was essential in facilitation of motor pathway by electrical stimulation. Eight subjects with sensory impairment following SCI and nine healthy subjects were recruited. Motor evoked potentials (MEP), silent period(SP) elicited by 120% motor threshold transcranial magnetic stimulation (TMS), and H-reflex elicited by median nerve stimulation were recorded on flexor carpi radialis (FCR) muscle before, during, immediately and 30 minutes after repetitive electrical stimulation (25 Hz, on/off=800ms/ 800 ms) on median nerve. In healthy subjects, the averaged amplitude of MEP increased to 154±29% of initial (P=0.01) after repetitive electrical stimulation. This increment became statically non-significant 30 min after the stimulation stopped. In subjects with SCI, the MEP did not change. The H-reflex and low frequency depression ratio did not change in both subjects. We concluded that the sensory afferent input was essential to facilitate the corticomotoneuronal excitability during peripheral nerve stimulation.
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