Agreement between pelvic floor muscle assessment methods in women with stress urinary incontinence: a cross-sectional study

Stress urinary incontinence (SUI) is associated with impaired pelvic floor muscle (PFM) function; however, the relationships and agreement among commonly used PFM assessment methods remain unclear. This study investigated the associations between digital vaginal palpation using the Modified Oxford Scale (MOS) and surface electromyography (sEMG) measurements, as well as the agreement between transperineal (TP-sEMG) and intravaginal (IV-sEMG) recordings in women with SUI. In this cross-sectional observational study, 25 women with SUI were recruited between December 25, 2025, and January 25, 2026. PFM function was assessed sequentially using MOS, TP-sEMG, and IV-sEMG. Associations between MOS scores and sEMG parameters were examined using Spearman''s rank correlation coefficient, whereas agreement between TP-sEMG and IV-sEMG was evaluated using intraclass correlation coefficients (ICCs) and Bland–Altman analysis. Moderate positive correlations were observed between MOS scores and selected sEMG parameters during the 5-s contraction protocol (ρ = 0.414–0.445, p < 0.05), whereas the remaining correlations were not statistically significant. Agreement between TP-sEMG and IV-sEMG was poor across the evaluated parameters (ICC = −0.136 to 0.162). Bland–Altman analysis revealed systematic bias for selected parameters and wide limits of agreement. These findings indicate generally limited associations between MOS scores and sEMG parameters and poor agreement between the two sEMG recording methods under the investigated conditions. However, they do not establish whether the methods assess distinct physiological constructs or provide complementary clinical information. Further studies with larger samples, standardized EMG acquisition and processing procedures, and validated reference methods are warranted to clarify their clinical relevance and potential interchangeability.