Background: The use of surface electromyography (sEMG) measurements to evaluate the bioelectrical activity of the pelvic floor muscle (PFM) during therapeutic intervention is now well established. This study investigates the diagnostic possibilities of sEMG in women with stress urinary incontinence (SUI). The aim of this study was to carry out objective assessments of the bioelectrical activity of the PFM in women after menopause and determine the prognostic value of sEMG for assessing the PFM in patients with SUI.
Methods: This was a prospective, observational study that evaluated the bioelectrical activity of the PFM in postmenopausal women with or without SUI (SUI group, n = 89 vs. non-SUI group, n = 62). The study was carried out between January 2013 and December 2018 at the Clinic of Urology (Wroclaw, Poland). The protocol for all sEMG measurements of PFM activity consisted of following elements: "baseline", "quick flicks", "contractions", "static hold", and "rest tone"; we then compared these results between groups. To determine the optimal cutoff level for sEMG activation of the PFM to detect the occurrence of SUI, we performed receiver operating characteristic (ROC) curve analysis (with Youden's index).
Results: Significantly lower results were obtained for all PFM measurements in women with SUI. The optimum diagnostic cutoff for "baseline" was 3.7 μV (area under curve (AUC), 0.63), "quick flicks" was 9.15 μV (AUC, 0.84), "contractions" was 11.33 μV (AUC, 0.80), "static hold" was 9.94 μV (AUC, 0.84), and "rest" was 3.89 μV (AUC, 0.63).
Conclusions: Measuring sEMG activity in the PFM may be a useful diagnostic tool to confirm the absence of SUI. We can expect that the sEMG activity of subjects with SUI will be lower than that of healthy people. In order to determine appropriate reference values for assessing sEMG activity data in the PFM, it is now necessary to conduct multicenter studies.
Keywords: pelvic floor muscle; surface electromyography; urinary incontinence.