DISRUPTED SLEEP IN THE ELDERLY--CIRCADIAN ETIOLOGY

描述(改编自调查人员摘要)：超过四分之一 的老年人抱怨说，他们在晚年经常醒来 15%的人报告说他们在早上5点以后无法入睡 先前的研究结果表明，大多数健康的人也会在清晨醒来 没有睡眠问题的老年人、没有抑郁症的老年人和有抑郁症的老年人 没有表现出任何与年龄相关的内在昼夜节律缩短的证据 句号。由目前拨款资助的研究表明，这一与年龄有关的 后半夜睡眠中断的增加不可能 可以用昼夜节律光重置的年龄相关变化来解释 敏感度。根据最近的分析，调查人员发现：1) 与年龄相关的昼夜节律相间隔的变窄，后者 部分睡眠可以保持稳定，导致明显的年龄相关性睡眠 睡眠对昼夜节律错位的易感性增加； 2)伴随昼夜节律变异性的年龄相关性增加 相位。假设这些与年龄相关的昼夜节律变化可能 占中断的高流行率的一个重要组成部分 在老年人中观察到睡眠和清晨醒来。 这意味着，在老年人中，实现和保持精确的(和 昼夜节律和睡眠时间之间的关系是 对巩固睡眠至关重要。调查人员对该事件的调查结果 光对人体节律的影响提示最佳相位关系 老年人睡眠和内源性昼夜节律之间的关系 通过适当地定时曝光到新的光曝光图案来实现 短暂的、间歇性的明亮光脉冲。 提出了四个可检验的假说：(I)褪黑激素和 老年人的体温节律和唤醒时间将出现在较早的小时 而不是生活在家里自己选择的睡眠-唤醒时间表的年轻人； (Ii)在该等自选附表的基线条件下， 年纪大的人在最后三分之一晚上的清醒程度会更高 受试者；(3)每天四次短暂暴露在晚间强光下将 足以建立和维持睡眠-觉醒周期的夹带 在最佳的昼夜节律阶段，导致最终的觉醒减少 夜间三分之一的时间和增强的日间警觉性；及(Iv)类似的 早晨的强光照射模式不会改善昼夜节律 相位错位。

DESCRIPTION (adapted from investigator's abstract): More than one-quarter of older people complain that they wake up frequently during the latter part of the night, with 15 percent reporting that they cannot sleep past 5 AM. Prior results show that early morning awakening also occurs in most healthy older people who have no sleep complaint, who are not depressed and who do not exhibit any evidence of age-related shortening of intrinsic circadian period. Studies funded by the current grant suggest that this age-related increase in sleep interruptions during the latter part of the night cannot be explained by an age-related change in circadian photic resetting sensitivity. Based on recent analyses, the investigators have found: 1) an age-related narrowing of the circadian phase interval over which the latter part of sleep can remain consolidated, leading to a marked age-related increase in the susceptibility of sleep to misalignment of circadian phase; and 2) an age-related increase in the variability of entrained circadian phase. It is hypothesized that these age-related circadian changes may account for a substantial component of the high prevalence of disrupted sleep and early morning awakening observed among older people. This implies that in older people, achieving and maintaining a precise (and narrow) relationship between circadian phase and the timing of sleep is crucial to attain sleep consolidation. The investigators' findings on the effect of light on human rhythms suggest that the optimum phase relationship between sleep and endogenous circadian rhythms in older people can be achieved by appropriately timed exposure to a novel light exposure pattern of brief, intermittent bright light pulses. Four testable hypotheses are proposed: (I) the phase of the melatonin and temperature rhythms and wake-time will occur at an earlier hour for older than for young adults living on self-selected sleep-wake schedules at home; (II) under base-line conditions on those self-selected schedules, wakefulness in the final third of the night will be higher for older subjects; (III) four brief exposures to evening bright light each day will be sufficient to establish and maintain entrainment of the sleep-wake cycle at an optimal circadian phase, resulting in reduced wakefulness in the final third of the night and enhanced daytime alertness; and (IV) a similar pattern of bright light exposure in the morning will not improve circadian phase misalignment.