Urgency urinary incontinence and the interoceptive network: a functional magnetic resonance imaging study

Abstract

Background Treatment of urgency urinary incontinence has focused on pharmacologically treating detrusor overactivity. Recent recognition that altered perception of internal stimuli (interoception) plays a role in urgency urinary incontinence suggests that exploration of abnormalities of brain function in this disorder could lead to better understanding of urgency incontinence and its treatment. Objectives 1) To evaluate the relationship between bladder filling, perceived urgency and activation at brain sites within the interoceptive network in urgency urinary incontinence 2) To identify coactivation of other brain networks that could affect interoception during bladder filling in urgency incontinence 3) To demonstrate interaction between these sites prior to bladder filling by evaluating their resting state connectivity Study Design We performed an observational cohort study using functional magnetic resonance imaging to compare brain function in 53 women with urgency urinary incontinence and 20 Controls. Whole-brain voxel-wise ANCOVAs were performed to examine differences in functional brain activation between groups during a task consisting of bladder filling, hold (static volume) and withdrawal phases. The task was performed at three previously established levels of baseline bladder volume, the highest exceeding strong desire to void volume. All women continuously rated their urge on a 0–10 point Likert scale throughout the task and a mixed measures ANOVA was used to test for differences in urge ratings. Empirically derived regions of interest from analysis of activation during the task were used as seeds for examining group differences in resting state functional connectivity. Results In both urgency urinary incontinent participants and Controls changes in urge ratings were greatest during bladder filling initiated from a high baseline bladder volume and urgency incontinent participants’ rating changes were greater than Controls. During this bladder filling phase urgency incontinent participant’s activation of the interoceptive network was greater than Controls, including in the left insula and the anterior and middle cingulate cortex. Urgency Incontinent Participant’s activation was also greater than Controls at sites in the Ventral Attention Network and Posterior Default Mode Network. Urgency incontinent participant’s connectivity was greater than Controls between a middle cingulate seed point and the Dorsal Attention Network, a “top down” attentional network. Control connectivity was greater between the mid-cingulate seed point and the Ventral Attention Network, a “bottom up” attentional network, Conclusions Increasing urge was associated with greater urgency incontinent participant than Control activation of the interoceptive network and activation in networks that are determinants of self-awareness (Default Mode Network) and of response to unexpected external stimuli (Ventral Attention Network). Differences in connectivity between interoceptive networks and opposing attentional networks (Ventra...

Methodology for a trial of brain-centered versus anticholinergic therapy in women with urgency urinary incontinence

“…We hypothesize that hypnotherapy will decrease abnormal brain activation in UUI patients and will modulate brain functional connectivity, and will investigate whether this normalization will be greater in hypnotherapy compared to pharmacotherapy. The fMRI methods and baseline findings have been previously published [14]. …”

“…FMRI uses brain oxygen level dependent (BOLD) signal on brain imaging as an indicator of neuronal activity. FMRI researchers commonly administer stimuli, or “tasks”, to elicit change in BOLD signal to compare differences between patients and controls [14]. UUI researchers have commonly used bladder filling as that task [7,8,14].…”

“…FMRI researchers commonly administer stimuli, or “tasks”, to elicit change in BOLD signal to compare differences between patients and controls [14]. UUI researchers have commonly used bladder filling as that task [7,8,14]. In addition to task oriented brain activation, specific brain regions also demonstrate similar fluctuations in BOLD signal over time that are intrinsic in nature [15].…”

“…We have reported the fMRI methodology and baseline differences in patients and controls [14], and will evaluate fMRI changes in patients following RCT interventions at 8 weeks.…”

“…(Figure 1). Details of the procedures, including the fMRI task, data acquisition and processing, and analytic methods have been previously published [14]. In brief, prior to fMRI, bedside cystometry is performed.…”