Pelvic floor nerve conduction studies: establishing clinically relevant normative data.

Objective: The purpose of this study was to establish data for normative distributions for pudendal and perineal nerve compound muscle action potential data in healthy women across a wide age range and varied history of vaginal deliveries.

Study Design: We studied 42 continent women, aged 20 to 67 years, including 29% nulliparous women with a disposable St. Mark's electrode to stimulate the pudendal nerve at the ischial spine by a transvaginal approach. The pudendal terminal motor latency and amplitude were detected with the use of surface patch electrodes overlying the external anal sphincter; the perineal responses were measured with the use of a surface ring electrode at the proximal urethra.

Results: None of the data were distributed normally and required the use of negative inverse and cube root transformations to create a normal distribution. Clinical correlations were found with advancing age and vaginal delivery.

Conclusion: The collection of these data allows for the definition of normal limits and begins the study of clinically important variables on test results and clinical outcomes.