Sleep bruxism (SB) is a sleep-related movement disorder, characterized by tooth grinding and/or clenching. The causes of SB range from psychosocial factors to an excessive sleep arousal response. Some studies showed that SB episodes during sleep are under the influences of transient activity of the brainstem arousal. Nocturnal groaning (NG) is a parasomnia characterized by an expiratory monotonous vocalization occurring during sleep, especially in REM sleep and during the second half of the night. The pathogenesis of NG remains still unclear and many hypotheses arose, ranging from the persistence of a vestigial ventilatory pattern rather than an expiratory upper airways' obstruction. Sleep microstructure fluctuation might modulate the NG, since the end of the NG episode usually is synchronized with a cortical arousal and an autonomic activation. Further studies should clarify the pathophysiology of SB and NG, especially when the two phenomena are associated.

中文翻译：

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磨牙症和夜间吟。

睡眠磨牙症（SB）是一种与睡眠有关的运动障碍，其特征是磨牙和/或咬合。SB的病因从社会心理因素到过度的睡眠唤醒反应。一些研究表明，睡眠中的SB发作受脑干唤醒的瞬时活动的影响。夜间吟（NG）是一种失眠症，其特征是在睡眠期间（尤其是在REM睡眠中和下半夜）出现呼气单调发声。NG的发病机制仍不清楚，并且出现了许多假说，其范围从残留的通气模式而不是上呼吸道的阻塞一直存在。睡眠微结构波动可能会调节NG，因为NG发作的结束通常与皮层唤醒和自主神经激活同步。进一步的研究应阐明SB和NG的病理生理，尤其是当两种现象相关时。