Multiple sclerosis (MS) is characterised by demyelinating lesions within the central nervous system, which can disrupt supraspinal and spinal pathways involved in pelvic floor muscle (PFM) control, potentially resulting in impaired activation and coordination. These dysfunctions contribute to neurogenic lower urinary tract symptoms, including urinary incontinence (UI). Surface electromyography (sEMG) reliably assesses PFM function and provides objective data undetected during routine examinations. This cross-sectional study aims to investigate the correlation between sEMG-derived PFM activity and the severity of UI. Furthermore, the study evaluates associations among disability levels, quality of life (QoL), physical activity, and fatigue in women diagnosed with MS. We hypothesise that impaired PFM activity is significantly associated with increased severity of UI, higher levels of disability and fatigue, reduced physical activity, and lower QoL.

Following ethical approval, this cross-sectional study enrolled female patients (30-50 years) diagnosed with MS according to the 2017 Revised McDonald Criteria. Inclusion criteria were UI as defined by the International Continence Society (ICS), an Expanded Disability Status Scale (EDSS) score below 6.5, and no cognitive or communication impairments. Exclusion criteria included refusal to participate, pregnancy, recent vaginal or cesarean delivery (within the last six months), pelvic organ prolapse, active urinary tract infection, or any alterations in MS-related medication within the preceding six months. PFM activity was assessed non-invasively using a biofeedback-assisted sEMG device (NeuroTrac Myoplus, Verity Medical Ltd, UK). After a training session, electrodes were placed at the 2 and 7 o'clock positions in the perianal area, with a reference electrode on the right thigh. The standardised protocol consisted of 10 cycles of 5-second maximal voluntary contractions (MVC) followed by 5-second baseline muscle activity (BMA), guided by verbal commands. The mean MVC (µV) of the active phase and the mean BMA (µV) of the resting state were recorded over a 50-second interval. The MVC–BMA difference was recorded, reflecting the net increase in PFM activity from rest to MVC. Clinical and functional parameters were evaluated using: EDSS, Neurogenic Bladder Symptom Score (NBSS; including total score and QoL score), International Consultation on Incontinence Questionnaire-Short Form (ICIQ-SF), Incontinence Impact Questionnaire-7 (IIQ-7), International Physical Activity Questionnaire (IPAQ), and Fatigue Severity Scale (FSS). Pearson’s correlation coefficients assessed relationships between UI severity, PFM activity, and clinical parameters.

17 female patients with MS were included in this preliminary analysis. Their sociodemographic, physical and clinical characteristics are summarized in Table 1. The Pearson correlation coefficients between the mean MVC, mean BMA, and the difference between mean MVC and mean BMA with FSS, IPAQ, ICIQ-SF, IIQ-7, NBSS total, and NBSSQoL are provided in Table 2. Statistical analysis revealed that MVC was significantly correlated with FSS, IPAQ, ICIQ-SF, IIQ-7, NBSS total, and NBSS-QoL scores (p < 0.05), but not with EDSS. On the other hand, BMA did not show any significant correlation with disease severity, fatigue, physical activity and severity of UI and neurogenic bladder symptoms. The mean MVC-BMA difference was significantly correlated with EDSS, FSS, IPAQ, ICIQ-SF, IIQ-7, NBSS total, and NBSS-QoL scores (p < 0.05).

While MVC reflects maximal contraction capacity and BMA represents resting muscle activity, the difference between MVC and BMA appears to better capture the functional ability of the PFM to increase activation above baseline. This parameter showed consistent associations with both clinical symptoms and disease severity, suggesting that net voluntary activation may be a more sensitive indicator of pelvic floor dysfunction in patients with MS.

As preliminary data, these findings highlight the need for further investigation into PFM activation in patients with MS. Although PFM activation appears to be associated with UI severity and QoL, additional studies are required to confirm these relationships and determine their clinical implications.