Spinal Excitability Changes Following Sensory Electrical Stimulation of The Forearm

Sensory electrical stimulation can be used to suppress tremor in Parkinson’s disease. This study investigated the central mechanism underlying this suppression in healthy participants. Reciprocal inhibition (RI) of the wrist flexors before and after a session of sensory electrical stimulation (SES) applied to the antagonistic extensor muscles was assessed using electromyography. It was hypothesized that a 15-minute session of SES, rated by participants as a 3 on a 0-10 pain scale, would produce an increase in RI. Seven of the 18 participants experienced an increase in RI at 0-5 minutes post stimulation, which returned to baseline at 10-15 minutes. The findings of the present experiment suggest that increases in RI are only observed in a “responders” subgroup consisting of predominantly male participants. More research is needed to understand the optimal stimulation intensity and any sex-linked factors that are important to produce reliable changes in reciprocal inhibition following sensory electrical stimulation