Sensory evoked cortical potentials of the lower urinary tract in healthy men.

AIMS: To assess the afferent innervation of various locations in the male lower urinary tract (LUT) using sensory evoked cortical potentials (SEPs).

METHODS: Twelve healthy men (mean age: 29.6 ± 7.2 years, mean height: 1.8 ± 0.1 m) underwent repetitive slow (0.5 Hz/1 ms) and fast (3 Hz/0.2 ms) electrical stimulations of bladder (dome/trigone) and urethral (proximal/membranous/distal) locations with simultaneous cortical SEP recording (Cz-Fz). Latencies (ms) and peak-to-peak amplitudes (μV) for SEP components P1, N1, and P2 were analyzed. Tibial SEPs were assessed as methodological control. The reproducibility was investigated from between visits and inter-rater assessments using Bland-Altman plots. Statistical tests comprised analysis of variance (ANOVA), linear regressions, and paired t-tests. Values are given as mean ± standard deviation.

RESULTS: Typical LUTSEPs with P1, N1, and P2 components were successfully detected (100% responder rate) for slow but less successfully for fast stimulation. The slow stimulation provided reproducible LUTSEPs with position specific N1 latencies: dome 125.6 ± 21.3 ms, trigone 122.9 ± 20.5 ms, proximal- 116.1 ± 21.4 ms, membraneous- 118.8 ± 29.3 ms, and distal urethra 108.8 ± 17.8 ms. Despite good inter-rater agreement, latency variability between and within subjects was higher for LUTSEPs than for tibial SEPs. N1 latencies became shorter (P < 0.01) with increasing subject age for bladder dome and distal urethra stimulation.

CONCLUSIONS: LUTSEPs can be successfully obtained for different LUT locations in men using slow electrical stimulation. Location specific differences in N1 latencies may indicate different local afferent innervation. Larger variability of LUTSEPs versus tibial SEPs may be related to the more challenging approach and afferent fibre access within the LUT. Further studies optimizing measurement and analysis approach are required.