MP54-10 SUBTYPES OF SENSORY SENSITIVITY IN OVERACTIVE BLADDER SYNDROME: RESULTS OF NEUROIMAGING AND SENSORY TESTING FROM THE SYMPTOMS OF LOWER URINARY TRACT DYSFUNCTION RESEARCH NETWORK (LURN)

Abstract

Introduction: Although Overactive Bladder Syndrome (OAB) has traditionally been considered a disorder of the lower urinary tract, a subset of patients reports a global increase sensory symptoms, suggesting central amplification of sensory perception may also be involved in this condition. In this study, OAB patients and Healthy Controls (HC) completed psychophysical auditory sensitivity testing and resting state functional magnetic resonance imaging (rs-fMRI) during naturalistic bladder filling (Lai et al 2018). Methods: OAB (N = 145, female = 52%, age = 57.61 ± 14.5 years) and HC (N = 97, female = 52%, age = 52.76 ± 15.38 years) participants completed rs-fMRI following ingestion of 350 ml of water, at bladder full and post-void empty states, respectively. Participants also completed questionnaires on urinary, pain and mood symptoms. A Generalized Sensory Sensitivity (GSS) score was calculated as a measure of global sensory sensitivity (widespread body pain, response to lights and sounds). Auditory testing was conducted with a pure tone audiometer, where 6, 3-s tones were presented binaurally at various intensity levels (40-90 dB, 2000Hz). After each tone, participants rated corresponding intensity and unpleasantness on a 0 to 100 scale. Results: 50 (34%) OAB patients scored ≥ 3 on the GSS and were sub-grouped as high GSS (h-GSS). Relative to the low GSS (l-GSS) group (N = 95) and HC (N = 97), h-GSS patients reported increased pain severity and interference, anxiety, and depression, and exhibited higher scores on the Genitourinary Pain Index (GUPI) pain subscore (all ps< 0.05). Interestingly, h-GSS and l-GSS groups did not differ in GUPI urinary symptoms or quality of life. Relative to l-GSS and HC groups, h-GSS patients reported increased hearing sensitivity on a hyperacusis questionnaire (P< 0.05), and exhibited higher unpleasantness in response to 60 and 70 dB tones (P< 0.05). Finally, h-GSS patients showed higher activity in sub-regions of the default mode network (DMN), relative to l-GSS [posterior cingulate cortex (PCC)] and HC (PCC and medial prefrontal cortex) in the post-voiding phase. Conclusion: OAB patients self-reporting higher GSS demonstrate increased pain, mood issues, and auditory sensitivity. They also show greater DMN activity after voiding, consistent with higher DMN activity in fibromyalgia - the prototypical central sensory amplification syndrome - and chronic pain disorders in general. These data indicate differential neurobiological mechanisms may underlie the manifestation of clinical subtypes in OAB.