Functional mapping of the pelvic floor and sphincter muscles from high-density surface EMG recordings

Abstract

Introduction and Hypothesis Knowledge of the innervation of pelvic floor and sphincter muscles is of great importance to understanding the pathophysiology of female pelvic floor dysfunctions. This study aims to present our high-density intravaginal and intrarectal electromyography (EMG) probes and a comprehensive innervation zone (IZ) imaging technique based on high-density EMG readings to characterize the IZ distribution. Methods Both intravaginal and intrarectal probes are covered with a high-density surface electromyography electrode grid (8 X 8). Surface EMG signals were acquired in 10 healthy female subjects during maximum voluntary contractions of their pelvic floor. EMG decomposition was performed to separate the motor unit action potentials (MUAPs) and then localize their IZs. Results High-density surface EMG signals were successfully acquired over the vaginal and rectal surfaces. The propagation patterns of muscle activity were clearly visualized for multiple muscle groups of the pelvic floor and anal sphincter. During each contraction, up to 218 and 456 repetitions of motor units were detected by the vaginal probe and the rectal probe, respectively. MUAPs were separated with their IZs identified at various orientations and depths. Conclusions The proposed probes are capable of providing a comprehensive mapping of the innervation zones of the pelvic floor and sphincter muscles. They can be employed as diagnostic and preventative tools in clinical practices.

Motor unit number estimation based on high-density surface electromyography decomposition

“…The duration of the entire procedure could be further significantly reduced if contractions are only performed at one fixed MVC level, as long as the fixed MVC level is kept the same for the purpose of consistently tracking of the disease progression. In addition, with promising decomposition results achieved (Peng et al, 2015, 2016), we expect to apply this new MUNE method on pelvic floor muscles, the motor unit number of which plays an important role in the pathophysiology of pelvic floor disorders but has never been estimated.…”

Innervation asymmetry of the external anal sphincter in aging characterized from high‐density intra‐rectal surface EMG recordings

“…These characteristics of HD‐sEMG enable the repeated and long‐term assessment of neuromuscular function while providing a wealth of information regarding the health of the muscle. However, limited effort has been made to apply HD‐sEMG to pelvic muscles, possibly because of the complexity of pelvic anatomy . A 64‐electrode intra‐rectal HD‐sEMG probe was developed in our lab to provide a direct contact and complete coverage of the EAS, while minimizing physical discomfort.…”

Female pelvic floor biomechanics

“…The pelvic floor consists of a complex and highly interdependent network of connective tissues and muscles designed to counteract gravitational forces, inertial forces and intra-abdominal pressures while providing support to the pelvic organs [1, 2]. When this network is compromised, pelvic floor disorders (PFDs) can occur including pelvic organ prolapse (POP).…”