Abstract
The purpose of this study is to analyze biological signals associated with nocturnal bruxism during sleep. Polysomnographic recordings were obtained with the multi-telemeter system from 5 male subjects (mean age 33.8) . Bruxism events were detected when elevations of masseter EMG activity exceeded 5%MVC level.
A total of 660 bruxism events were recorded and divided into clenching (24.1%), grinding (58.9%) and combined (17.0%) types according to jaw movement patterns. Changes in sleep stage, heart rate, and FFT of EEG were analyzed for all the bruxism types. Results are as follows;
1) Mean masseter's EMG activity of all bruxism events was 9.3% MVC, with a mean duration time of 9.1 seconds. The mean EMG activity of the clenching type was significantly higher than that of the grinding type. However, there was no significant difference between mean durations of clenching and grinding type bruxism events.
2) Sleep stage generally became lighter after bruxism event occurred. This tendency was typical in the clenching type.
3) FFT analysis of EEG revealed an increase of mean power frequency after bruxism events. EEG mean power frequency of the grinding type was higher than that of the clenching type.
4) Heart rate increased gradually at least 8 seconds before the onset of bruxism events and its peak was observed right after the offset of bruxism events.
