Assessment of awake bruxism-Combinational analysis of ecological momentary assessment and electromyography

Purpose: No consensus exists regarding the examination methods and assessment criteria for awake bruxism (AB). In this study, masticatory muscle activity measured using electromyography (EMG) was recorded simultaneously with the ecological momentary assessment (EMA) of bruxism events. Data were collected to identify distinctive EMG parameters in AB. Methods: A total of 104 individuals were classified into the bruxism (BR) or control (CO) groups based on clinical findings. The participants recorded EMA on a tablet device under continuous EMG recording using a data log-type wireless EMG device. For EMA recording, a warning was randomly provided three times each hour for five hours. A receiver operating characteristic (ROC) curve was obtained based on EMA and EMG events. Maximum voluntary contraction (MVC) at the time of maximum bite force was set at 100%. The muscle activity was assessed as a relative value. Results: Based on discriminant analysis, analysis of participants who had four or more positive clenching EMA responses was appropriate. The assessed parameters for the EMG cutoff value determination procedure, which combined EMG and EMA, resulted in a cutoff value that enabled the distinction between the BR and CO groups. The area under the ROC curve was 0.77 and the cut-off value was 3.2 events/hour under the EMG of 20% MVC with a duration of >= 1 s. Conclusions: This is the first study to report a combined analysis of the EMA and EMG. These results suggest its effectiveness as a cutoff value for AB screening.