Velocity-dependent suppression of somatosensory evoked potentials during movement.

Sensory transmission is known to be impaired during movement of the stimulated body part. This phenomenon is manifested by a decrease of perceptual acuity and a correlated decrease in the size of somatosensory evoked potentials (SEPs). The goal of the present study was to define the relationship between SEP amplitude and speed of movement. SEPs were elicited by brief (25 msec) loading of the wrist flexor muscles. Stimuli were applied while the wrist joint was stationary or moving voluntarily at one of several velocities. In all subjects, SEP amplitude was approximately inversely related to speed of movement at the time of stimulation. The findings refine and extend studies suggesting the velocity dependence of sensory suppression during movement.