Short latency somatosensory evoked potentials during active hand movements.

This study was designed to investigate the effect of active movement on spinal and cortical evoked responses. During voluntary hand movements the cervical and cortical short latency somatosensory evoked potentials (SEP) elicited by stimulation of the median nerve at the wrist were studied in nine healthy subjects. The latencies of the SEPs were not affected by active movements whereas the peak to peak amplitudes of the main cervical (N13-P15) and the main cortical (N20-P25) deflections were significantly reduced. The cortical subcomponents (N16 and N17), probably reflecting thalamic and thalamocortical activity, were not significantly affected by movements. The amplitude reductions in the cervical and cortical recordings might be related to proprioceptive feedback from the muscle afferents.