Sensory evoked potentials of the human lower urinary tract

Abstract

PURPOSE: To investigate feasibility and reliability of recording sensory evoked potentials (SEPs) following lower urinary tract (LUT) electrical stimulation. SEPs might reveal improved insights in afferent processing within specific locations of the human LUT. SUBJECTS AND METHODS: Electrical stimulation with 0.5Hz and 3Hz was applied to the bladder dome, trigone, proximal, and distal urethra using a transurethral catheter. SEPs were recorded cortical at the Cz electrode, referenced to the Fz electrode. All measurements were repeated three times for reliability assessment using intraclass correlation coefficients (ICCs). RESULTS: Ten healthy female subjects with mean heights of 168±6cm and mean age of 23±4years were included. The most prominent and consistent SEPs landmark across different locations was the first negativity peak (N1). Following 0.5Hz stimulation N1 was reliably recorded at 128.8±23.8ms (ICC=0.88), 141.9±51.5ms (ICC=0.83), 133.1±32.1ms (ICC=0.90), and 132.5±33.6ms (ICC=0.81) at the bladder dome, trigone, proximal and distal urethra, respectively in all subjects. Following 3Hz stimulation, no reliable SEPs could be recorded. CONCLUSIONS: SEPs can be reliably recorded from different locations of the LUT following 0.5Hz stimulation with a characteristic N1 response at about 130ms. These latencies are compatible with a conduction velocity in the range of 3-10m/s which corresponds to transmission by A-delta fibers. The inability to retrieve reliable responses at 3Hz stimulation might potentially be related to less involvement of fast conduction fibers (i.e. A-beta) in afferent sensation along the human LUT. The value of a more distinct diagnosis of sensory sensation in LUT disorders needs to be evaluated in further studies.