Diagnostic accuracy of sleep bruxism scoring in absence of audio-video recording: a pilot study

Based on the most recent polysomnographic (PSG) research diagnostic criteria, sleep bruxism is diagnosed when >2 rhythmic masticatory muscle activity (RMMA)/h of sleep are scored on the masseter and/or temporalis muscles. These criteria have not yet been validated for portable PSG systems. This pilot study aimed to assess the diagnostic accuracy of scoring sleep bruxism in absence of audio-video recordings.

Ten subjects (mean age 24.7 ± 2.2) with a clinical diagnosis of sleep bruxism spent one night in the sleep laboratory. PSG were performed with a portable system (type 2) while audio-video was recorded. Sleep studies were scored by the same examiner three times: (1) without, (2) with, and (3) without audio-video in order to test the intra-scoring and intra-examiner reliability for RMMA scoring.

The RMMA event-by-event concordance rate between scoring without audio-video and with audio-video was 68.3 %. Overall, the RMMA index was overestimated by 23.8 % without audio-video. However, the intra-class correlation coefficient (ICC) between scorings with and without audio-video was good (ICC = 0.91; p < 0.001); the intra-examiner reliability was high (ICC = 0.97; p < 0.001). The clinical diagnosis of sleep bruxism was confirmed in 8/10 subjects based on scoring without audio-video and in 6/10 subjects with audio-video.

Although the absence of audio-video recording, the diagnostic accuracy of assessing RMMA with portable PSG systems appeared to remain good, supporting their use for both research and clinical purposes. However, the risk of moderate overestimation in absence of audio-video must be taken into account.