Urinary incontinence, core morphology and their impact on balance and fatigue in multiple sclerosis: an observational study

Introduction Multiple Sclerosis (MS) is a chronic condition affecting the central nervous system, often leading to urinary incontinence (UI), balance disturbances, and fatigue. This study examines the relationship between UI, core muscle morphology, balance, and fatigue in patients with MS (PwMS) to inform rehabilitation strategies. Methods A cross-sectional observational study was conducted with 27 PwMS (17 with UI and 10 without). Abdominal muscle thickness (transversus abdominis (TA), internal obliques, and external obliques) was assessed via ultrasound. UI-related Quality of Life was evaluated using questionnaires (ICIQ-SF and I-QOL), balance was assessed with the Trunk Impairment Scale (TIS) and Berg Balance Scale (BBS), and fatigue was measured using the Modified Fatigue Impact Scale (MFIS). Results Significant correlations were observed between UI, TA thickness during contraction and balance with the TIS demonstrating greater sensitivity than the BBS. PwMS with UI exhibited reduced TA thickness and poorer scores in balance and fatigue, particularly in the cognitive subscale of the MFIS. Logistic regression revealed that the severity of UI predicts functional balance, with an overall model accuracy of 70.8%. Conclusions Core dysfunction may link UI, balance and fatigue in PwMS. Strengthening the TA and pelvic floor muscles should be a rehabilitation priority to improve UI, postural stability, and daily function.