Scalp recorded somatosensory evoked potentials to posterior tibial nerve stimulation in humans

The somatosensory evoked potentials (SEPs) produced by stimulation of the right and left posterior tibial nerves individually and also by their simultaneous stimulation were recorded in 84 adult normal subjects up to 150 msec after the stimulus by electrodes placed on the cranial vertex and by rows of electrodes over the sagittal and coronal lines using references on the ear or in the nasopharynx. The statistical distribution of the latencies of their different peaks was established. The effect of simultaneous stimulation of right and left posterior tibial nerves on the early SEP components was described. Some details of the anatomy of the rolandic sulcus were inferred from the amplitude distribution of these potentials.