title: Optimal placement of bipolar surface EMG electrodes in the face based on single motor unit analysis.
abstract: Locations of surface electromyography (sEMG) electrodes in the face are usually chosen on a macro-anatomical basis. In this study we describe optimal placement of bipolar electrodes based on a novel method and present results for lower facial muscles. We performed high-density sEMG recordings in 13 healthy participants. Raw sEMG signals were decomposed into motor unit action potentials (MUAPs). We positioned virtual electrode pairs in the interpolated monopolar MUAPs at different positions along muscle fiber direction and calculated the bipolar potentials. Electrode sites were determined where maximal bipolar amplitude was achieved and were validated. Objective guidelines for sEMG electrode placement improve the signal-to-noise ratio and may contribute to reduce cross talk, which is particularly important in the face. The method may be regarded as an important basis for improving the validity and reproducibility of sEMG in complex muscle areas.
authors.affiliation: Department of Orthodontics, Albert Ludwigs University, Freiburg, Germany. bernd.lapatki@uniklinik-ulm.de
authors.forename: Bernd G
authors.initials: BG
authors.lastname: Lapatki
authors.forename: Robert
authors.initials: R
authors.lastname: Oostenveld
authors.forename: Johannes P
authors.initials: JP
authors.lastname: Van Dijk
authors.forename: Irmtrud E
authors.initials: IE
authors.lastname: Jonas
authors.forename: Machiel J
authors.initials: MJ
authors.lastname: Zwarts
authors.forename: Dick F
authors.initials: DF
authors.lastname: Stegeman
mesh_terms: D000328:Adult; D003627:Data Interpretation, Statistical; D004566:Electrodes; D004576:Electromyography; D005145:Face / Q000033:anatomy & histology / Q000294:innervation* / Q000502:physiology*; D005152:Facial Muscles / Q000166:cytology / Q000502:physiology*; D005260:Female; D006801:Humans; D008046:Lip / Q000294:innervation / Q000502:physiology; D008297:Male; D009046:Motor Neurons / Q000502:physiology*; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D055815:Young Adult