BACKCROUND- Sexual dysfunction symptomatology is a common manifestation in a variety of neurological and nonneurological disorders. Neurologists are frequently poorly prepared to systematically analyze and evaluate these symptoms. The present review discusses male sexual dysfunction in the areas of erectile and ejaculatory performance and provides the clinician with basic concepts of neuroanatomy, neurophysiology, clinical history, diagnosis, and treatment. REVIEW SUMMARY- The parasympathetic and sympathetic nervous systems play complementary but incompletely understood roles in erectile function. A noncholinergic-nonadrenergic pathway mediated by nitric oxide and facilitated by acetylcholine may represent the final step in the generation of erections by promoting blood flow into the dilated cavernosal lacunar spaces. Erection is then maintained by trapping blood via veno-occlusive mechanisms. Seminal emission and ejaculation are primarily dependent on adequate sympathetic function. The somatic nervous system is responsible for the initial afferent tactile information of the sexual response and for the perineal muscular contraction at the time of ejaculation. Clinical history allows for an initial impression regarding organicity vs. psychogenicity of the erectile difficulties and distinguishes three principal disorders of ejaculation (premature ejaculation, dry ejaculation, and ejaculatory incompetence). CONCLUSIONS- Erectile dysfunction can be organic (neurogenic, endocrinogenic, iatrogenic, vasculogenic) or psychogenic. Most patients will require baseline hormonal determinations. Nocturnal penile tumescence studies are crucial to determine presence of psychogenicity. Neurophysiological intracavernosal pharmacotherapy and noninvasive vacuum erection devices should precede consideration of prostheses. There are no laboratory studies for ejaculatory disorders. Premature ejaculation and ejaculatory incompetence are treated by the sex therapist. Dry ejaculation may require withdrawal of potential iatrogenic causes, treatment of underlying erectile dysfunction (if present), or use of special invasive techniques for those seeking treatment of infertility.
