Computer-guided EMG activity collection during usual and unusual oral behaviors

Objectives: Little is known about contraction patterns of masticatory muscles during numerous usual and unusual oral behaviors. Our aim was to assess electromyographic (EMG) activity of the masticatory muscles during different oral tasks performed under computer guidance.

Methods: EMG activity was recorded from the right-side masseter, anterior temporalis and suprahyoid muscles by means of surface electrodes in eleven subjects (5 men, 6 women; age=34.6±10.8 years), who performed twenty-two tasks (Table 1) standardized with the support of explanatory text, pictures and animations. During experiments, well-timed task performance was achieved by extensive use of countdown and progress bars. Dual-tone multi-frequency sounds acted as task markers for off-line analyses. Synchronously, a video was recorded by a digital camera. Data was analyzed by ANOVAs.

Results: Task- and muscle-related EMG activities are summarized in Table 1. Significant interaction between muscle and gender was found (F=6.7; p=0.001), as masseter and suprahyoid muscles were more active in males, whereas stronger temporalis activity was found in females.

Conclusions: The proposed approach provided further insight into task-, muscle- and gender-specific EMG patterns during usual and unusual oral behavior.

Table 1