Naturalistic Bladder Filling Reveals Subtypes in Overactive Bladder Syndrome That Differentially Engages Urinary Urgency-Related Brain Circuits: Results From the Symptoms of Lower Urinary Tract Dysfunction Research Network (LURN)

Abstract

Purpose: Overactive bladder (OAB) may be attributed to dysfunction in supraspinal brain circuits. Overactive bladder participants enrolled in the LURN (Symptoms of Lower Urinary Tract Dysfunction Research Network) study reported sensations of urinary urgency during a bladder-filling paradigm while undergoing brain functional MRI to map supraspinal dysfunction. Materials and Methods: OAB participants and controls (CONs) completed 2 resting-state functional MRI scans following consumption of 350 mL water. Scans were conducted at fuller and emptier bladder states, interleaved with voiding. Urgency ratings (0-10) were assessed. Patterns of urgency during bladder filling were investigated using latent class trajectory models. Clusters of participants encompassing each pattern (ie, subtype) were derived from aggregated groups of OAB and CON independent of diagnosis.

Editorial Comment

“…In 2020 the same natural filling protocol was piloted in a younger cohort of healthy controls. 2 Similar to the present study, the pilot also found correlation of functional connectivity with urgency rating and voided volume. The 2 clusters discovered in the current study may reflect distinct phenotypes of OAB but also may reflect limitations of the protocol.…”

Reply By Authors

“…Intensity of bladder urgency during naturalistic bladder filling depends on a number of factors, including bladder sensitivity phenotypes and changes in brain connectivity (as reported in this paper), 1 the amount and timing of fluid intake, overall fluid status (eg, a dehydrated participant may have slower diuresis in response to fluid challenge), and bladder volume. In a naturalistic bladder-filling paradigm, we have no control over the volume of urine inside the bladder at any given time.…”