INVESTIGATION OF MONOPOLAR MULTI-CHANNEL SURFACE EMG OF THE EXTERNAL ANAL SPHINCTER MUSCLE

摘要: AIM: This study proposes a new method to investigate the geometry of fibres external anal sphincter (EAS) muscle using high density surface electromyogram (EMG). METHODS: Monopolar EMG signals recorded an array electrodes placed in circular direction have no common mode (CM) components if are circular, with constant depth within and parallel detection array. In this case monopolar can be estimated from SD compared experimental ones. Thus, presence CM physiological origin was used provide indications about EAS. Surface were EAS 12 subjects (7 females 5 males) probe carrying three arrays 16 electrodes. Single motor unit (MU) discharge times identified obtained these as triggers compute average action potential each MU. The amount MU (MUAP) analyzed respect radial (estimated by CoV MUAP amplitude arrays) position along canal (indicated higher amplitude). estimation error computed difference between original signal reconstructed (ARVe) normalized w.r.t. (ARVm). RESULTS: contribution single MUAPs is lower for MUs located more superficially at canal. CONCLUSION: Presence low voltages on related that, confirmed anatomical studies, only Large present deeply or internally Moreover, large also interference EMG, suggesting that there crosstalk far co-contracting muscles (e.g. puborectalis, glutei) deeper non-cylindrical geometry. ACKNOWLEDGEMENT: work sponsored Projects TASI (Else Kroner-Fresenius-Stiftung, Compagnia di San Paolo), TIFNI (Regione Piemonte, Italy).