Neurobiology of erectile dysfunction in multiple sclerosis

OBJECTIVE: To analyze the neurological alterations responsible for impotence in multiple sclerosis. METHODS: We conducted a pharmacologic erection test and a neuroandrologic profile study in 11 patients with multiple sclerosis and impotence. This study consisted in: bulbocavernosus EMG, S2-S4 evoked potentials, somatosensory potentials of pudendal nerve, electromyography of cavernous smooth muscle (SPACE), sympathetic skin response (SSR) and cystometry. RESULTS: The most frequent neurological lesion was complete suprasacral (7 cases; 64%) and parasympathetic (7 cases; 64%) lesions. The parasympathetic lesions were of the upper motor neuron type in 6 of the 7 cases (86%). Peripheral autonomic [sympathetic in 2 cases (18%); parasympathetic in 1 case (9%)] and pudendal lesions (3 cases; 27%) were also observed. CONCLUSIONS: The main cause of impotence in multiple sclerosis could be ascribed to a suprasacral lesion. Some cases also present peripheral autonomic lesions.