Cerebral-evoked response from stimulation of dorsal nerve in impotent men

Cerebral-evoked responses from 128 uncategorized, impotent men were compared with responses from 17 healthy age-height matched controls, after stimulation of two penile sites, and one tibial nerve at the ankle. Our goal has been to establish a simple screening test to identify neurogenic impotence in patients with normal superficial sensation. High-frequency stimulation at 5.7 c/s and minimal repetitions (300) per trial, allowed thirty to forty minute sessions in alert subjects. With these methods, the amplitudes of cerebral responses at N2 were most informative. All volunteers had measurable amplitude while 11.9 percent of patients did not. An additional 4.5 percent of patients had amplitude suppression of 2 SD compared with the control mean, suggesting that as many as 16.4 percent of such patients may have neural damage. Prolonged latencies alone were rare and not included in this total. Ninety-two of these 128 patients had Doppler flow studies, and only 2 showed both Doppler and electrical abnormalities. This suggests that neurogenic problems may often be independent of vascular disease. This evoked-response screen of the entire genitocerebral neuraxis offers a safe method of identifying a portion of those patients with neurogenic impotence.