Multiple sleep bruxism data collected using a self-contained EMG detector/analyzer system in asymptomatic healthy subjects

• Published in: Sleep & breathing 2012-12, Vol.16 (4), p.1069-1072
• Main Authors: Minakuchi, Hajime, Sakaguchi, Chiyomi, Hara, Emilio S., Maekawa, Kenji, Matsuka, Yoshizo, Clark, Glenn T., Kuboki, Takuo
• Format: Article
• Language: English
• Subjects: Adult; Biological and medical sciences; Dentistry; Disorders of higher nervous function. Focal brain diseases. Central vestibular syndrome and deafness. Brain stem syndromes; Electromyography - instrumentation; Electromyography - statistics & numerical data; Equipment Design; Female; Fundamental and applied biological sciences. Psychology; Humans; Internal Medicine; Male; Masseter Muscle - physiopathology; Medical sciences; Medicine; Medicine & Public Health; Monitoring, Ambulatory - instrumentation; Monitoring, Ambulatory - statistics & numerical data; Multiple sclerosis and variants. Guillain barré syndrome and other inflammatory polyneuropathies. Leukoencephalitis; Nervous system (semeiology, syndromes); Neurology; Original Article; Otolaryngology; Otorhinolaryngology; Pediatrics; Pneumology/Respiratory System; Polysomnography - instrumentation; Polysomnography - statistics & numerical data; Reference Values; Signal Processing, Computer-Assisted - instrumentation; Sleep Bruxism - diagnosis; Sleep Bruxism - physiopathology; Sleep disorders; Sleep. Vigilance; Vertebrates: nervous system and sense organs
• ISSN: 1520-9512; 1522-1709
• DOI: 10.1007/s11325-011-0602-1

Purpose Small, self-contained electromyographic (EMG) detector/analyzer (D/A) devices have become available for the detection of jaw muscle activity events above threshold. These devices claim to be less intrusive to the subjects sleep so it is less prone to induce disturbed sleep. The objective of this study was to evaluate for night-to-night variability and examine for a systematic alteration on the first night in EMG levels. Methods Ten asymptomatic healthy volunteers (mean age, 26.8 ± 3.78) were recorded for six sequential nights in their home environment using EMG D/A system. The device yields a nightly EMG level above threshold score on a 0–4 level. Because the data are categorical and nonparametric, the data of the ten subjects across six nights were submitted to a Friedman repeated measures ANOVA. The significant level was set as alpha equal to 0.05. Results The median and mode values of the subjects were tabulated and analyzed and we did not find a significant difference in EMG D/A level across the six nights ( p  = 0.287, Kendall's coefficient of concordance = 0.124, Friedman two-way repeated measures ANOVA). The data did show clear and substantial night-to-night variability. Conclusion Substantial night-to-night variability in masseter EMG activity levels was clearly observed in our subjects. There was no evidence of a suppressed or elevated first-night effect-like variability on masseter muscle EMG level seen in these subjects using a small portable self-contained EMG detector/analyzer. These data suggest that recordings should be at least 5–6-nights duration to establish a reasonable measure of an individual's average nightly masseter EMG level.