Validity of Bulbocavernosus Reflex Latency and Pudendal Somatosensory Evoked Potential in Impotence

This study was designed to verify the validity of bulbocavernosus reflex latency(BCRL) and pudendal somatosensory evoked potential(SEP) in the evaluation of neurogenic erectile dysfunction and to lay out a scheme to uplift the diagnostic accuracy of BCRL and pudendal SEP. Eighty four subjects who were referred to Seoul National University Hospital EMG laboratory for the evaluation of the erectile dysfunction were examined. At first, history taking, physical examination, measurement of serum hormone level, rigiscan with audiovisual sexual stimulation were performed. In the next step, intracorporial papaverine injection, nocturnal penile tumescence test, BCRL and pudendal SEP were performed as indicated. Then the results of BCRL and pudendal SEP were compared to the final diagnosis obtained through additional studies. Psychogenic cause was most common and neurogenic, vascular, and hormonal causes followed. The diagnostic sensitivity of BCRL and pudendal SEP in the discrimination of neurogenic cases from nonneurogenic cases was 89.5% and 93.7%, respectively. The specificity was 89.7% and 64.7% in order. Among twenty seven subjects with abnormal BCRL or pudendal SEP, eight subjects were confirmed as psychogenic impotence at the final diagnosis. But psychogenic impotence was not found among nine subjects who had abnormal BCRL and pudendal SEP. Twenty three subjects with abnormal BCRL were divided into delayed latency group and no response group. Among thirteen subjects of delayed latency group, psychogenic cases were six and among ten subjects of no response group, psychogenic case was not found. In the evaluation of neurogenic impotence, BCRL was a sensitive and specific tool while pudendal SEP was sensitive but less specific. BCRL alone or pudendal SEP alone would be inadequate for the evaluation of neurogenic impotence, especially in discrimination with psychogenic one. To improve diagnostic accuracy in the evaluation of impotence, BCRL and pudendal SEP should be checked out all together. In the situation when only BCRL is available, it is recommendable to take unevokable bulbocavernosus reflex as meaningful.

Pudendal somatosensory evoked potential and bulbocavernosus reflex testing in erectile dysfunction

Pudenal somatosensory evoked potential (PSEP) and bulbocavernosus reflex (BCR) testing have been reported to be useful in the evaluation of erectile dysfunction and neurogenic bladder. 461 patients with sexual dysfunction were studied to determine the usefulness of the above tests. Abnormality of PSEP was found significantly in upper motor neuron (UMN) type spinal cord patients and average prolonged P1 latency was 47.4 +/- 9.8 msec. Lower motor neuron (LMN) type spinal cord patients revealed great abnormality in BCR latency with an average value of 44.9 +/- 14.5 msec on the right and 44.2 +/- 15.6 msec on the left. Additionally significant differences were obtained in patients with diabetes mellitus, pelvic trauma and spinal cord lesion of the UMN type in the study of PSEP. There was also a significant difference in the patients with diabetes mellitus, pelvic trauma and spinal cord lesion of the LMN type in the BCR study. The findings of our study suggest that PSEP together with BCR study is useful in assessing the integrity of the sacral reflex arc and the central afferent pathway, in differentiating the lesion site and in providing basic data for the management plan in sexual rehabilitation. Furthermore, because erection is under the influence of both the somatic and autonomic nervous system, BCR study and PSEP combined with currently studied electrical activity of the corpus cavernosum would provide a more accurate evaluation of the neurogenic erectile dysfunction patients.