Protocol for a prospective, single-arm pilot trial assessing the clinical and supraspinal neural effects of non-invasive transcranial neuromodulation in adults with overactive bladder

Background Overactive bladder (OAB) is a prevalent condition characterized by urinary urgency, frequency, and nocturia, with or without urge urinary incontinence. It significantly affects quality of life and is associated with increased rates of depression and sexual dysfunction. Lower urinary tract (LUT) control relies on coordinated activity across peripheral, spinal, and supraspinal networks. Individuals with OAB exhibit abnormal supraspinal network activity. Current treatments primarily target peripheral pathways and have limited efficacy. Repetitive transcranial magnetic stimulation (rTMS) offers a non-invasive approach to modulate networks involved in LUT control. Methods This prospective, single-center, single-arm, pilot trial evaluates the clinical and neural effects of neuronavigated rTMS in individuals with OAB. Baseline functional MRI (fMRI) guides individualized targeting of OAB-relevant regions. Participants undergo five sessions of low-frequency stimulation of the pelvic supplementary motor area (SMA) followed by high-frequency rTMS to the dorsolateral prefrontal cortex (DLPFC). Primary endpoints are changes in LUT control network functional connectivity (FC) during full and empty bladder conditions. Secondary outcomes include changes in OAB symptoms, urinary frequency and incontinence episodes, quality of life, and patient-perceived bladder condition. Pelvic floor muscle (PFM) electromyography (EMG) recorded during the first and fifth sessions provides exploratory physiological outcomes. Clinical outcomes are assessed immediately, three and six weeks post-treatment. Discussion This study is the first to evaluate non-invasive neuromodulation of supraspinal regions in individuals with OAB. By targeting brain networks involved in LUT control, this neuronavigated approach may improve FC and provide a novel therapeutic strategy for individuals with OAB refractory to conventional treatments. Trial Registration Number NCT06198439. Participant enrollment and follow-up have been completed.