Division of Sleep Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
Sleep Med. 2011 Jan;12(1):83-8. doi: 10.1016/j.sleep.2010.06.007. Epub 2010 Nov 18.
Periodic limb movements in sleep (PLMS) show a time-of-night pattern, with most movements at the beginning of the night. Our study aimed to determine whether this pattern is due to an endogenous circadian rhythm, like that in the related movement disorder Restless Legs Syndrome (RLS).
Four healthy older adults with a screening PLMI>20 were studied in an inpatient forced desynchrony protocol with an imposed sleep-wake cycle of 20 h for 12 "nights," allowing separation of circadian and sleep homeostatic influences on leg movements. We recorded sleep polysomnographically throughout each scheduled episode, including left and right anterior tibialis EMG.
PLMS in Stage 2 showed both a significant time-within-sleep pattern and a significant circadian rhythm. The circadian rhythm in PLMS peaked at the circadian phases when usual sleep onset occurs, preceding the evening rise in melatonin secretion.
In our subjects, the circadian pattern of PLMs expression was very similar to that previously reported in patients with RLS. This evidence for a circadian rhythm in PLMS has implications for treatment and provides direction for future studies of the pathophysiology of this movement disorder.
睡眠周期性肢体运动（PLMS）呈现出一种夜间时间模式，大多数运动发生在夜间开始时。我们的研究旨在确定这种模式是否是由于内源性昼夜节律引起的，就像相关的运动障碍不宁腿综合征（RLS）一样。
四名筛查 PLMI>20 的健康老年人在住院强制去同步协议中接受研究，该协议采用 20 小时的强制睡眠-觉醒周期进行 12 个“夜晚”，允许对腿部运动的昼夜节律和睡眠内稳态影响进行分离。我们在每个预定发作期间进行睡眠多导睡眠图记录，包括左侧和右侧胫骨前肌 EMG。
在 2 期的 PLMS 显示出明显的睡眠内时间模式和明显的昼夜节律。PLMS 的昼夜节律在通常的睡眠开始时出现的昼夜相位达到峰值，早于褪黑素分泌的傍晚上升。
在我们的研究对象中，PLMS 表达的昼夜模式与先前报道的 RLS 患者非常相似。PLMS 昼夜节律的这一证据对治疗具有影响，并为进一步研究这种运动障碍的病理生理学提供了方向。
