Nocturnal erections, differential diagnosis of impotence, and diabetes.

In this study it is shown that monitoring of nocturnal penile tumescence (NPT) is an objective method for determining the erectile status of patients who complain of impotence. The characteristics of 11 diabetic patients with abnormal NPT, 11 patients with normal NPT and no medical disorders, and 11 normal men are presented. Also described are several sociodemographic characteristics of the first 100 patients undergoing an NPT evaluation as part of a screen for patients seeking implantation of a penile prosthesis. It is suggested that NPT monitoring should be a component of the differential diagnosis procedure for every patient who complains of impotence and that it provides a tool for the concentrated study of the mechanisms of erection and impotence.