Sleep Bruxism is a Disorder Related to Periodic Arousals During Sleep

TLDR

Sleep bruxism is an arousal‑related phenomenon characterized by transient arousals occurring every 20–40 s during non‑REM sleep and organized by a cyclic alternating pattern. The study compared sleep architecture between bruxers and matched controls and examined how bruxism episodes relate to transient arousals. Polysomnography was performed on six bruxers and six matched controls to assess sleep structure and arousal patterns. Bruxers exhibited no differences in standard sleep metrics but had significantly more transient arousals, with most bruxism episodes occurring during stages 1–2, linked to the cyclic alternating pattern, elevated heart rate, and tibial muscle jerks, supporting a unified arousal‑based model.

Abstract

There is evidence that sleep bruxism is an arousal-related phenomenon. In non-REM sleep, transient arousals recur at 20- to 40-second intervals and are organized according to a cyclic alternating pattern. Polysomnographic recordings from six subjects (two females and four males) affected by sleep bruxism (patients) and six healthy age-and gender-matched volunteers without complaints about sleep (controls) were analyzed to: (1) compare the sleep structure of bruxers with that of non-complaining subjects; and (2) investigate the relations between bruxism episodes and transient arousals. Patients and controls showed no significant differences in conventional sleep variables, but bruxers showed a significantly higher number of the transient arousals characterized by EEG desynchronization. Bruxism episodes were equally distributed between non-REM and REM sleep, but were more frequent in stages 1 and 2 (p < 0.0001) than in slow-wave sleep. The great majority of bruxism episodes detected in non-REM sleep (88%) were associated with the cyclic alternating pattern and always occurred during a transient arousal. Heart rate during the bruxism episodes (69.3 ± 18.2) was significantly higher (p < 0.0001) than that during the pre-bruxing period (58.1 ± 15.9). Almost 80% of all bruxism episodes were associated with jerks at the anterior tibial muscles. The framework of the cyclic alternating pattern offers a unified interpretation for sleep bruxism and arousal-related phenomena.