Sensory evoked potentials of the human lower urinary tract

We investigated the feasibility and reliability of recording sensory evoked potentials after lower urinary tract electrical stimulation. Sensory evoked potentials might reveal improved insights into afferent processing in specific locations of the human lower urinary tract.

Electrical stimulation (0.5 and 3 Hz) was applied to the bladder dome and trigone, and the proximal and distal urethra using a transurethral catheter. Cortical sensory evoked potentials were recorded at the Cz electrode with reference to the Fz electrode. All measurements were repeated 3 times for reliability assessment using the ICC.

Ten healthy female subjects with a mean ± SD age of 23 ± 4 years and a mean height of 168 ± 6 cm were included in the study. The most prominent, consistent sensory evoked potential landmark across different locations was the first negative peak. In all subjects after 0.5 Hz stimulation, the first negative peak was reliably recorded at a mean of 128.8 ± 23.8, 141.9 ± 51.5, 133.1 ± 32.1 and 132.5 ± 33.6 milliseconds (ICC 0.88, 0.83, 0.90 and 0.81) at the bladder dome, trigone, proximal and distal urethra, respectively. After 3 Hz stimulation, no reliable sensory evoked potentials could be recorded.

Sensory evoked potentials can be reliably recorded from different lower urinary tract locations after 0.5 Hz stimulation with a characteristic negativity at about 130 milliseconds. These latencies are compatible with a conduction velocity in the range of 3 to 10 m per second, corresponding to transmission by A-δ fibers. The inability to retrieve reliable responses at 3 Hz stimulation might potentially be related to less involvement of fast conduction fibers, ie A-β, in afferent sensation along the human lower urinary tract. The value of a more distinct diagnosis of sensory sensation in lower urinary tract disorders must be evaluated in further studies.