CEREBRAL EVOKED-POTENTIALS AFTER STIMULATION OF THE POSTERIOR URETHRA IN MAN

Cerebral evoked potentials (EPs) were recorded in 25 neurologically normal subjects aged 22-73 years (mean 44.0) after stimulation of the posterior urethra (PU) and the pudendal nerve. After maximal PU stimulation 2 different configurations of the potential were found. In 12 cases a simple bi-triphasic wave form was recorded while in 12 cases there was a bifid form of the first negative wave. In 1 case identical EPs were recorded after PU and pudendal nerve stimulation. It was concluded that (1) PU stimulation excites fibres in the pudendal nerve at higher stimulation strength, resulting in a bifid wave form of the cerebral evoked potential in some individuals, (2) the most prominent negative peak, N1, with a latency of 102.1 ± 13.2 msec, is the most reproducible part of the PU-evoked potential, (3) the N1 is probably transmitted through Aδ fibres localized in the pelvic nerves, (4) there are differences between individuals concerning pudendal and pelvic nerve involvement in afferent innervation of the urethra. © 1990.