Autonomic nervous activities associated with bruxism events during sleep

Abstract Objectives: To confirm the relationship between sleep bruxism (SB) and autonomic nervous (AN) activities to elucidate SB physiology. Methods: Subjects included 11 healthy males (mean age, 24.7 ± 2.3 years). These data were recorded in the sleep laboratory using a system composed of a two-axis accelerometer, an infrared camera, electroencephalography, electromyography, and electrocardiography. Time lapse analysis confirmed correlations between AN activity and SB events during sleep in subjects. Relationships between SB strength and length and AN activity were evaluated. Results: Sympathetic nerve (SN) and parasympathetic nerve (PSN) activities occurred significantly in 93.3% of cases (p < 0.01), with similar predictable patterns during SB. Furthermore, SB length and SN activity in seven of the subjects (four subjects, p < 0.05; three subjects p < 0.01), and PSN and SB muscle activities (% maximum voluntary contraction) in five subjects (four subjects, p < 0.05; one subject, p < 0.01) were significantly correlated. Discussion: The authors believe that SB is closely related to SN as well as PSN activities and may control the AN system.