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. Markʹs 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.