Scalp Topography of Lower Urinary Tract Sensory Evoked Potentials

Stéphanie Van Der Lely,Thomas M Kessler,Martina D Liechti,Ulrich Mehnert

doi:10.1007/s10548-020-00796-z

Stéphanie Van Der Lely, Thomas M Kessler + Show 2 more

Open Access

https://doi.org/10.1007/s10548-020-00796-z

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Abstract

Impaired lower urinary tract (LUT) afferents often cause LUT symptoms. Assessment of LUT afferent pathways is possible using bipolar cortical sensory evoked potential (SEP) recordings with the active electrode at the vertex during electrical stimulation in the LUT. This study aimed to investigate the topographical distribution and microstates of lower urinary tract sensory evoked potentials (LUTSEPs) using different stimulation frequencies. Ninety healthy subjects (18–36 years old, 40 women) were randomly assigned to one of five stimulation locations [bladder dome; trigone; proximal, membranous (men only) or distal urethra]. Cycles of 0.5 Hz/1.1 Hz/1.6 Hz electrical stimulation were applied using a custom-made catheter. Cortical activity was recorded from 64 surface electrodes. Marker setting was performed manually on an individual subject-level for the P1, N1, and P2 components of vertex recordings. N1 and P2 topographies presented with central negativities and positivities around the vertex. Regarding topographical distribution, Randomization Graphical User interface (RAGU) analyses revealed consistent frequency effects and microstates for N1/P2. Higher stimulation frequencies resulted in decreasing map strength for P1, N1, and P2. LUTSEP topographies suggest central generators in the somatosensory cortex, which are not detectable in a bipolar set-up. The observed frequency effect indicates fiber refractoriness at higher frequencies. The multichannel approach allows more comprehensive assessment of LUTSEPs and might therefore be sensitive to pathological changes. Examinations in patients with LUT symptoms are needed to further investigate this biomarker.

Highlights

The brain’s electrical response to ascending sensory input from the lower urinary tract (LUT) conveys important knowledge about the processing of afferent information
Gender, body weight, and body height, different stimulation parameters and urine production during stimulation should be considered for lower urinary tract sensory evoked potentials (LUTSEPs) analysis (Gerstenberg et al 1991; Knüpfer et al 2018; van der Lely et al 2019a)
The following subjects’ characteristics were entered as additional independent variables: age, female gender, location (BD, as comparator to other locations), body weight, body height, produced urine volume during the corresponding stimulation cycle, absolute stimulation intensity. Using this modelling set-up, we examined the effect of various measurement settings and subjects’ characteristics on LUTSEP amplitudes and latencies

Summary

Introduction

The brain’s electrical response to ascending sensory input from the lower urinary tract (LUT) conveys important knowledge about the processing of afferent information. While tibial and pudendal nerve stimulation are well established in clinical practice, the measurement of SEPs in response to repetitive electrical stimulation of the LUT has not yet progressed so far The latter, has proven feasible in healthy subjects (Ganzer et al 1991; Gerstenberg et al 1991; Gregorini et al 2015, 2013; Knüpfer et al 2018) and patients (Hansen et al 1989; Sarica et al 1996) with location-specific lower urinary tract sensory evoked potential (LUTSEP) latencies and amplitudes. Gender, body weight, and body height, different stimulation parameters and urine production during stimulation should be considered for LUTSEP analysis (Gerstenberg et al 1991; Knüpfer et al 2018; van der Lely et al 2019a)

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