Erectile dysfunction in men with obstructive sleep apnea: an early sign of nerve involvement.

Erectile dysfunction (ED) is common in men with obstructive sleep apnea (OSAS) but no completely convincing hypotheses about the underlying pathogenic mechanisms have been published in the literature. The aims of the present study were to assess the presence of ED in a group of OSAS patients without daytime respiratory failure and to determine whether this dysfunction was related to peripheral nerve involvement. Evaluation of the bulbocavernosus reflex (BCR) and the somato-sensory evoked potentials of pudendal nerve (PSEPs), the most widely established method of documenting pudendal neuropathies as being the cause of impotence, was performed in 25 patients. Data on BCR were compared with those of 25 healthy males volunteers matched for age. BCR was altered in 17 patients: in 6 it was elicited while in 11 it had a prolonged latency and reduced amplitude. Patients with altered BCR presented an higher AHI, an higher percentage of sleep time spent with SaO2 <90% (TST90) and a lower daytime PaO2. Six patient had clinically silent neurophysiological signs of mild polyneuropathy. The degree of OSAS and gas exchange alteration was more severe in patients with polyneuropathy than in those with isolated BCR alteration. ED is a common finding in OSAS patients and this alteration seems to be related to a nerve dysfunction. The development of nerve dysfunction is associated with a more severe degree of OSAS and nocturnal hypoxia.