The assessment of nocturnal REM erection in the differential diagnosis of sexual impotence.

A new method for differentiating psychogenic from organic cases of sexual impotence is described based on the assesst of nocturnal REM erection in nine patients. It is our tentative impression that in psychogenic impotence nocturnal REM erection may be normal in amount and degree and an excellent indicator of erectile potential. In these cases a marked discrepancy exists between the amount and degree of nocturnal erection and the patient's daytime performance level attained during attempted coitus or masturbation. In the organic patients, on the contrary, such a discrepancy does not exist; instead, the maximal nocturnal erection attained corresponds closely to and mirrors the patient's impaired waking performance. This new method may be very useful in the diagnosis, prognosis, and decision as to type of treatment, especially in difficult cases.