Sexual disorders may be assessed in diabetic patients with neurophysiological investigations of the perineum including electromyographic detection of perineal floor muscles, sacral latency, somatosensory evoked potentials of the pudendal nerve, sympathetic skin response and nerve conduction velocity of the dorsal nerve of the penis. Alteration of sympathetic skin response and sensory dysfunction (reduction of the velocity or reduction in the amplitude of the distal sensory potential, alteration of the pudendal cortical evoked potentials) are the more frequent signs of perineal diabetic neuropathy.