Psychology Department and Interdepartmental Neuroscience Program, Northwestern University, Evanston, Illinois, USA.
J Int Neuropsychol Soc. 2012 May;18(3):490-500. doi: 10.1017/S135561771200001X. Epub 2012 Feb 3.
Whereas patients with Alzheimer's disease (AD) experience difficulties forming and retrieving memories, their memory impairments may also partially reflect an unrecognized dysfunction in sleep-dependent consolidation that normally stabilizes declarative memory storage across cortical areas. Patients with amnestic mild cognitive impairment (aMCI) exhibit circumscribed declarative memory deficits, and many eventually progress to an AD diagnosis. Whether sleep is disrupted in aMCI and whether sleep disruptions contribute to memory impairment is unknown. We measured sleep physiology and memory for two nights and found that aMCI patients had fewer stage-2 spindles than age-matched healthy adults. Furthermore, aMCI patients spent less time in slow-wave sleep and showed lower delta and theta power during sleep compared to controls. Slow-wave and theta activity during sleep appear to reflect important aspects of memory processing, as evening-to-morning change in declarative memory correlated with delta and theta power during intervening sleep in both groups. These results suggest that sleep changes in aMCI patients contribute to memory impairments by interfering with sleep-dependent memory consolidation.
与阿尔茨海默病（AD）患者形成和检索记忆困难不同，他们的记忆障碍可能部分反映了睡眠依赖巩固过程中未被识别的功能障碍，而正常情况下，睡眠依赖巩固过程可以稳定跨皮质区域的陈述性记忆存储。遗忘型轻度认知障碍（aMCI）患者表现出局限性的陈述性记忆缺陷，许多患者最终会被诊断为 AD。aMCI 患者是否存在睡眠中断，以及睡眠中断是否导致记忆障碍尚不清楚。我们在两晚时间内测量了睡眠生理学和记忆，发现 aMCI 患者的 2 期纺锤波比年龄匹配的健康成年人少。此外，与对照组相比，aMCI 患者的慢波睡眠时间较少，睡眠期间的 delta 和 theta 功率较低。睡眠期间的慢波和 theta 活动似乎反映了记忆处理的重要方面，因为两组中，陈述性记忆在傍晚到清晨的变化与睡眠期间的 delta 和 theta 功率相关。这些结果表明，aMCI 患者的睡眠变化通过干扰睡眠依赖的记忆巩固导致记忆障碍。
