MP07-16 MAPPING PELVIC FLOOR HYPERTONICITY IN WOMEN WITH IC/BPS USING HIGH-DENSITY SURFACE EMG

Abstract

INTRODUCTION AND OBJECTIVE: Pelvic floor hypertonicity (PFH) is a debilitating symptom of interstitial cystitis/bladder pain syndrome (IC/BPS). The diagnosis and assessment of PFH are based on subjective pelvic examinations, and results between examiners may vary. Precise assessment is critical to the clinical diagnosis and management of PFH. The objective of this study is to provide innovative techniques to objectively assess neurogenic PFH in women with IC/BPS using an intra-vaginal high-density surface electromyography (HD-sEMG) probe. METHODS: Seven female subjects (44±13 yr.) with IC/BPS were recruited. A full pelvic exam was administered to identify hypertonic muscles. Intra-vaginal HD-sEMG was then acquired at rest from a novel 64-channel HD-sEMG probe, as shown in Figure 1(a). Z-scores were calculated using the subjects without hypertonicity as a reference population, as shown in Figure 1(b). Root-mean-squared (RMS) amplitude during resting state was calculated from differential signals for each channel to define a hypertonicity index. Innervation zones (IZs) were identified from the bipolar mapping of decomposed signals, and summarized into an IZ distribution mapping. RESULTS: Of the 7 subjects recruited, 5 had normal pelvic floor muscle tone and 2 exhibited hypertonicity upon muscle palpation. Women with PFH demonstrated a much higher hypertonicity index (12.6±3.5 vs. 4.5±1.2). The hypertonic zone defined by the RMS mapping coincided with the digital hypertonic muscle assessment, as shown in Figures 1(c) and 1(d) for two subjects without hypertonicity, and Figures 1(e) and 1(f) for the two subjects with hypertonicity. Motor units were decomposed, and the corresponding IZs were localized, as shown in Figures 1(g) and (h) for two women without hypertonicity, and Figures 1(i) and (j) for the women with hypertonicity. CONCLUSIONS: This study represents the first effort to employ intra-vaginal HD-sEMG to assess PFH in women with IC/BPS. Our results demonstrate the feasibility of HD-sEMG to provide a quantitative analysis of PFH and provide a precise localization of hypertonic muscles and IZs. The proposed HD-sEMG based techniques provide promising tools for clinical diagnosis and treatment of PFH, such as the personalized guidance of BoNT injections.Source of Funding: This study received funding support from the SUFU Foundation and NIH DK113525.