Evaluation of erectile dysfunction with continuous monitoring of penile rigidity.

Measurement of nocturnal penile tumescence or circumferential expansion is a valuable method for the diagnosis of erectile impotence. However, only a few investigations have been made of penile rigidity during tumescence with a single isolated measurement. A new method of continuous and simultaneous recording of nocturnal penile rigidity and circumferential expansion (tumescence) was used in 105 patients with erectile impotence. The method provided several findings concerning nocturnal penile erection. Circumferential expansion was not always accompanied by penile rigidity. A dissociation of rigidity between the tip and base of the penis was observed in some patients. Shortened episodes and low amplitude of rigidity also were seen. Of 11 patients with psychogenic impotence diagnosed by conventional methods 3 (27.3 per cent) showed abnormal nocturnal rigidity and 8 of 94 (8.5 per cent) with organic impotence diagnosed by conventional methods showed normal nocturnal rigidity. Because of its ambulatory character the continuous measurement of nocturnal penile rigidity is of value in defining features of nocturnal penile erection and differentiating psychogenic from organic impotence.