Pudendal somatosensory evoked potentials - A standardized assessment for males and females

ObjectiveTo evaluate configuration- and sex-related differences in pudendal somatosensory evoked potential (SEP) waveform characteristics, tolerability, response stability, and test-retest reliability in healthy adults. MethodsPudendal SEPs were recorded from forty-two able-bodied adults (20 females, 22 males) across multiple electrode configurations that varied in anode-cathode placement for both sexes, and in laterality (unilateral and bilateral) for females only. Tibial SEPs were also recorded as a reference control. Peak-to-peak amplitudes were compared across configurations and between sexes and nerves using linear mixed-effects models. SEP latency was summarized descriptively. Tolerability (self-reported 1-10 Likert scale) was analyzed with cumulative link mixed models. Peak-to-peak amplitude stability was computed from exponential fits of cumulative averages and compared across configurations and nerves. Test-retest reliability for SEP latency and peak-to-peak amplitudes was assessed using intraclass correlation coefficients and Bland-Altman analyses. ResultsElectrode configuration had no effect on peak-to-peak amplitude in females or males, and no sex-based amplitude differences were observed. Tolerability varied significantly by configuration, where the configuration with the clitoral cathode and bilateral anodes was rated least tolerable in females, and the configuration with the anode on the glans and the cathode on the proximal shaft was least tolerable in males. Tibial nerve stimulation was consistently rated as more tolerable than pudendal, with a larger difference observed in females. On average, pudendal SEP amplitudes stabilized at 282 stimuli in females and 324 in males, with no differences across configurations nor compared to tibial SEPs. Test-retest analyses showed no systematic bias and revealed moderate-to-good reliability, with latency measures demonstrating greater reproducibility than peak-to-peak amplitudes. ConclusionsPudendal SEP amplitudes and response stability were robust to electrode configuration, but tolerability differed across configurations, highlighting the need to consider electrode placement when designing protocols to improve participant comfort. Test-retest analyses demonstrated moderate-to-good reproducibility, particularly for latency measures, supporting the reliability of pudendal SEPs for longitudinal or repeated assessments. SignificanceThese findings establish the feasibility and reliability of pudendal SEPs in healthy adults and provide guidance for optimizing stimulation locations in future research.