Reproducibility of surface EMG in the human masseter and anterior temporalis muscle areas.

The aim of this study was to test the hypothesis that surface electromyography (sEMG) recordings, made at mandibular rest position from the masseter and temporalis anterior areas, are intra- and inter-session reproducible. A template was designed and built to permit the correct electrode placement from one session to the next session. A sample of 18 subjects was examined. Two groups, homogeneous for age, sex, and craniofacial morphology were selected. The first group included asymptomatic subjects with no signs or symptoms of temporomandibular joint dysfunction (TMD) and the second group included patients suffering from muscle-related TMD. Data were obtained from different sEMG recordings made at mandibular rest position in the same session and in different sessions, repositioning the electrodes using a template designed for that purpose. The electromyograph used in this, study is part of the EMG K6-I Win Diagnostic System. Results showed that reproducibility of sEMG signals from the masseter and anterior temporalis areas at mandibular rest position is possible.