Polysomnographic scoring of sleep bruxism events is accurate even in the absence of video recording but unreliable with EMG-only setups

Kirsi Sipilä,Sami Myllymaa,Katja Myllymaa,Anu Muraja-Murro,Susanna Westeren-Punnonen,Reijo Lappalainen,Tomi Miettinen,Juha Töyräs,Esa Mervaala,Taina Hukkanen

doi:10.1007/s11325-019-01915-2

Abstract

PurposeTo determine the accuracy of scoring masticatory muscle activity (MMA) events in seven different polysomnography (PSG) setups.MethodsNineteen volunteers (13 females, 6 males, age 31.1 ± 12.9 years, 12 self-proclaimed bruxers) attended one-night PSG recording, supplemented with audio, video, and a separate frontal electroencephalography electrode set (FES). The same examiner scored the MMA events with seven different setups, with varying number of channels available: (1) one, (2) two, and (3) four EMG channels, (4) PSG without audio or video (PSG-N), (5) home PSG with FES and audio (FES-A), (6) PSG with audio (PSG-A), and (7) PSG with audio and video (PSG-AV). A subset (n = 10) of recordings was scored twice to determine intra-scorer reliability. MMA indices and accuracy of scoring the events in different setups were compared against PSG-AV.ResultsThe intra-class correlation coefficient (ICC) between PSG-AV and PSG-A was high (0.940, p < 0.001) as well as for FES-A (0.927, p < 0.001), whereas for PSG-N, it was lower (0.835, p < 0.001); for setups with only EMG channels, coefficients were very low (ICC < 0.100 for all). Intra-examiner reliability was high (ICC > 0.939 for all setups), with the exception of PSG-N (ICC = 0.764, p = 0.002). When comparing against the MMA events scored in PSG-AV, the sensitivity of MMA event recognition for PSG-A was 78.5% and specificity 95.5%, which were substantially higher than sensitivity (52.0%) and specificity (87.2%) of PSG-N.ConclusionsMMA event scoring accuracy with PSG-A or FES-A is almost comparable to PSG-AV. Since precise event recognition is essential for accurate MMA scoring, it is evident that one cannot rely exclusively on EMG.

Highlights

Sleep bruxism (SB) is masticatory muscle activity (MMA) that occurs involuntarily during the sleep [1]
The MMA indices scored with the PSG with audio (PSG-A) setup are very consistent and comparable to the indices scored with the PSG with audio and video (PSG-AV) setup: the intra-class correlation coefficient (ICC) between PSG-A and PSG-AV was
Similar to the estimates made with ICC, strong linear correlation with the MMA indices of PSG-AV setup was found with the PSG-A and frontal electroencephalography electrode set (FES)-A setups, a slightly weaker correlation with PSG-N with the weakest correlations present with all EMG setups (Table 1)

Summary

Introduction

Sleep bruxism (SB) is masticatory muscle activity (MMA) that occurs involuntarily during the sleep [1]. Verification is needed for the results of a higher MMA scoring accuracy when sleep stage scoring is included [21] or when only the MMA events during sleep periods are taken into account in the assessment of SB activity [18]. This further verification is needed due to the fact that even though it is true that many of the OFA and OMA events (26–72%) occur during short periods of wakefulness [12, 18], so too do some of the MMA events (26%, [12])

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