Department of Oral Rehabilitation and Regenerative Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ward, Okayama, 700-8525, Japan.
Sleep Breath. 2012 Dec;16(4):1069-72. doi: 10.1007/s11325-011-0602-1. Epub 2012 Jan 26.
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.
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.
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.
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.
小型、独立的肌电图（EMG）检测仪/分析仪（D/A）已可用于检测阈上的咀嚼肌活动事件。这些设备声称对受试者的睡眠侵入性更小，因此不太容易引起睡眠紊乱。本研究的目的是评估夜间变异性，并检查 EMG 水平在第一夜是否存在系统变化。
10 名无症状健康志愿者（平均年龄 26.8±3.78 岁）在家中环境中使用 EMG D/A 系统连续记录 6 晚。该设备在 0-4 级水平上产生每晚 EMG 水平超过阈值的分数。由于数据是分类和非参数的，因此将 10 名受试者的 6 晚数据提交给 Friedman 重复测量方差分析。显著水平设定为 alpha 等于 0.05。
对受试者的中位数和众数进行了制表和分析，我们没有发现 6 晚 EMG D/A 水平有显著差异（p=0.287，Kendall 一致性系数=0.124，Friedman 双向重复测量方差分析）。数据确实显示出明显的、实质性的夜间变异性。
我们的受试者中明显观察到咀嚼肌 EMG 活动水平的夜间变异性很大。使用小型便携式独立 EMG 检测仪/分析仪，在这些受试者中没有观察到咀嚼肌 EMG 水平的第一夜效应样抑制或升高的变异。这些数据表明，为了确定个体夜间平均咀嚼肌 EMG 水平的合理测量值，记录应至少持续 5-6 晚。
