Lockley S W, Skene D J, Butler L J, Arendt J
School of Biological Sciences, University of Surrey, Guildford, UK.
Sleep. 1999 Aug 1;22(5):616-23. doi: 10.1093/sleep/22.5.616.
Sleep is controlled by both circadian and homeostatic mechanisms. As the light-dark cycle is the most important time cue in humans, blind individuals may have circadian rhythm disorders including sleep. The aim of the study was to assess sleep with simultaneous measurement of an endogenous marker of the circadian clock, namely 6-sulphatoxymelatonin (aMT6s).
59 registered blind subjects were studied in their own homes.
Subjects completed daily sleep and nap diaries for at least four weeks, wore activity monitors continuously, and collected urine samples over 48 hours each week for 3-5 weeks for assessment of aMT6s rhythms.
The most sensitive indicator of a circadian rhythm disorder was day-time napping. Subjects with normally entrained (NE) aMT6s rhythms had fewer naps of a shorter duration than abnormally entrained (AE) or free-running (FR) subjects. The timing of these naps was not random; significantly more naps occurred within a five-hour range before and after the aMT6s acrophase (phi (phi)) than outside this range. Disorders in the timing and duration of night sleep in AE subjects manifested as either a permanent advance (advanced sleep phase syndrome, ASPS) or delay (delayed sleep phase syndrome, DSPS). In FR subjects there were transient advances and delays in sleep timing that paralleled aMT6s timing with increased night sleep duration and reduced number and duration of day-time naps associated with a normal aMT6s phase.
Changes in sleep and activity rhythms reflect changes in circadian phase.
睡眠受昼夜节律和稳态机制的双重控制。由于明暗周期是人类最重要的时间线索，盲人可能存在包括睡眠在内的昼夜节律紊乱。本研究的目的是通过同时测量昼夜节律钟的内源性标志物——6-硫酸氧褪黑素（aMT6s）来评估睡眠情况。
对59名登记在册的盲人受试者在其家中进行研究。
受试者连续至少四周记录每日睡眠和小睡日记，持续佩戴活动监测器，并在3至5周内每周收集48小时尿液样本以评估aMT6s节律。
昼夜节律紊乱最敏感的指标是日间小睡。aMT6s节律正常同步（NE）的受试者比节律异常同步（AE）或自由运行（FR）的受试者小睡次数更少且持续时间更短。这些小睡的时间并非随机；在aMT6s峰值相位（φ）前后5小时范围内发生的小睡明显多于该范围之外。AE受试者夜间睡眠的时间和时长紊乱表现为永久性提前（提前睡眠相位综合征，ASPS）或延迟（延迟睡眠相位综合征，DSPS）。在FR受试者中，睡眠时间存在短暂的提前和延迟，与aMT6s时间同步，夜间睡眠时间增加，日间小睡次数和时长减少，且与正常aMT6s相位相关。
睡眠和活动节律的变化反映了昼夜节律相位的变化。
