Assessment: Neurological Evaluation of Male Sexual Dysfunction

Overview. Male sexual dysfunction includes disorders of libido and of erectile and ejaculatory function. Erectile dysfunction or impotence is a common symptom in many neurologic diseases. Peripheral neuropathies, cauda equina syndrome, pelvic and pudendal nerve lesions, and spinal cord trauma and diseases as well as many disorders of higher brain centers, such as trauma, parkinsonism, Alzheimer's disease, multiple sclerosis, and cerebrovascular insufficiency, are common causes of sexual dysfunction. Furthermore, vascular abnormalities, many drugs, and psychological disorders associated with disturbance of neurologic or neuromuscular function may also be associated with impotence. These facts have led to the increasing involvement of the neurologist in the evaluation of impotence. There are now several increasingly effective surgical and nonsurgical methods of treating impotence. The effectiveness and therefore the selection of treatment in an impotent patient is, in part, dependent on the diagnosis. Recent studies showing that intracorporeal injection of vasoactive substances is effective in producing erections have, in many ways, altered the traditional diagnostic approach while offering treatment that had not previously existed. For example, intracorporeal injection of papaverine was noted to be more effective in neurogenic impotence. A functional erection produced by this procedure in effect rules out a vascular cause of impotence and the need for vascular diagnostic studies or vascular surgery. Demand for more accurate diagnostic tools for evaluating impotence has increased the use of many of these tools within the field of neurology. The neurologist is often the primary physician the impotent patient depends upon for diagnosis and advice. In impotent patients, failure to address the issue of sexual dysfunction may adversely affect the patient's quality of life. Increasingly, however, patients are being referred specifically for the neurologic investigation of impotence, ejaculatory disturbances, and anorgasmia with the following question—is this patient's sexual problem neurologic? Although the primary causes of ejaculatory disturbances such as retrograde ejaculation and secondary organic anorgasmia—the inability to achieve orgasm—may be neurologic, this review will concentrate on the evaluation of erectile dysfunction.