Pelvic floor muscle function differs between postmenopausal women with and without stress urinary incontinence: An...

Electromyography (EMG) is a well-established method for the quantification of pelvic floor muscle (PFM) activity. The aim of the present study was to evaluate the strength and activity of the urethral sphincter (US) and levator ani muscles (LAMs) by analyzing EMG variables for these PFMs separately using an airbag-type stretchable/inflatable electrode array (ASEA) device. In addition, the study assessed the predictive value of surface EMG (sEMG) signals obtained via ASEA in postmenopausal women with stress urinary incontinence (SUI). The study included an SUI group (n=67) and a healthy control group without pelvic floor dysfunction (n=65). sEMG recordings of the US and LAMs comprised the following components: i) Anterior resting potential; ii) maximum voluntary contraction (MVC); iii) tonic contraction potential (TCP); iv) endurance contraction potential (ECP); and v) posterior resting potential. Receiver operating characteristic (ROC) curve analysis was also performed to determine the optimal cut-off levels for sEMG activation of the PFMs. Muscle strength assessed using bidigital palpation and the modified Oxford grading system revealed that the scores in the SUI group were lower than those in the control group. Similarly, the sEMG activities measured using the ASEA device were significantly lower in the SUI group, particularly the MVC, TCP and ECP activities in the US and LAMs. ROC curve analysis demonstrated that the US and specific LAMs, namely the puborectalis and pubococcygeus muscles, demonstrated cut-off values with discriminative ability for SUI. However, the in sEMG of the iliococcygeus muscles did not significant differ between the two groups, The present study indicates that US defects and dysfunctional LAMs play an important role in the pathogenesis of SUI. Furthermore, region-specific assessment of US and LAMs may support the development of reliable and optimized treatment strategies for the precise rehabilitation of PFMs.