Feedback Stimulation on Polysomnographic Recordings in Patient with Sleep Bruxism

Objectives: To investigate the physiological characteristics of sleep bruxism and if bruxism can be inhibited by a newly developed electrical feedback stimulation system during sleep. Methods: Ten bruxers (6 M, 4 F) slept in the laboratory for three continuous nights including one adjustment night, one night for baseline recordings, and one night with feedback stimulation. Polysomnographic recordings of electroencephalography (EEG), electro-oculography (EOG), and electromyography (EMG) of masseters were obtained. During the third night, a biofeedback system based on automatic detection of EMG activity associated with contractions of the jaw muscles and electrical stimulation (below a pain threshold) applied to the right masseter whenever the EMG activity was detected. Number of EMG episodes and duration in each sleep stage with or without feedback stimulation were analyzed. Results: Increased EMG activity indicating bruxism appeared in all sleep stages. ANOVA showed that, when the feedback system was used, the number of EMG episodes was not significantly changed (P = 1.000). The duration of EMG activity was not significantly different at each sleep stage, however, the total duration of the EMG activity was significantly decreased from 285 ± 11 s to 239 ± 11 s (P = 0.010). The total sleep duration was not significantly changed (P = 0.825), however, the sleep duration was significantly decreased (P = 0.001) in stage 3 and 4, and significantly increased (P = 0.007) in the REM stage compared to baseline recording. Additional physiological characteristics (heart rate and respiration rate) were not significantly influenced by the feedback stimulation (P > 0.386). Conclusion: This preliminary and short-term study showed that the feedback system is able to inhibit the parafunctional activities of masseter muscle during sleep, however, it may also influence the sleep structures.

Supported by ASEM-UDO foundation: DD 2004-002.