The clinical assessment of erectile dysfunction: a comparison of nocturnal penile tumescence monitoring and intracavernosal injections.

One hundred and fifty-nine men with erectile dysfunction were assessed with Rigiscan monitoring of nocturnal penile tumescence (NPT) and response to intracavernosal injections (ICI) of papaverine or prostaglandin E1. A satisfactory NPT, suggestive of psychogenic causation, was recorded in 58%, whereas 15% had clearly impaired NPT. There was a significant association between presence of vascular disease, diabetes and impairment of NPT. For ICI, only 32% showed a satisfactory response, with 48% clearly impaired. Of the 92 men with satisfactory NPT, 40% HAD clearly impaired and 41% satisfactory ICI response. Of the 51 men with satisfactory ICI response, 8% had clearly impaired and 74.5% satisfactory NPT. There was no association between ICI response and history of vascular disease. We conclude that monitoring of NPT by Rigiscan, and without sleep monitoring, is a valuable diagnostic procedure. In contrast, because of the high proportion of false negative results. ICI monitoring is of very limited diagnostic value. The explanation for false negative ICI responses, however, could prove to be of considerable theoretical and clinical importance.