Frequency distribution of the number and amplitude of electromyographic waveforms of the masseter muscle during sleep in patients with a clinical diagnosis of sleep bruxism
Ai Kudo, Taihiko Yamaguchi, Saki Mikami, Miku Saito, Toshinori Nakajima, Masana Maeda, Mebae Takahashi, Sota Takahashi, Akihito Gotouda
Abstract
OBJECTIVE: This study aimed to clarify frequency distribution of number and peak amplitude of electromyographic (EMG) waveforms of sleep bruxism (SB) in outpatients with clinical diagnosis of SB (probable bruxer: P-bruxer). METHODS: Subjects were 40 P-bruxers. Masseteric EMG during sleep was measured at home using a wearable EMG system. EMG waveforms with amplitude of more than two times the baseline and with duration of 0.25 s were extracted as SB bursts. Clusters of bursts, i.e. SB episodes, were also scored. RESULTS: There were large variations among the subjects in numbers of SB bursts and episodes and in burst peak amplitude. As for burst peak amplitude within a subject, a wide right-tailed frequency distribution was shown with the highest frequency at the class of 5-10% maximum voluntary contraction. CONCLUSION: The number and amplitude of SB waveforms for P-bruxers were distributed over a wide range, indicating the existence of large individual differences.