Department of Psychology and Neuroscience, University of Massachusetts, Amherst, MA, USA.
Prog Brain Res. 2011;191:75-89. doi: 10.1016/B978-0-444-53752-2.00012-6.
Healthy aging is characterized by a diminished quality of sleep with decreased sleep duration and increased time awake after sleep onset. Older adults awaken more frequently and tend to awaken less from rapid eye movement (REM) sleep and more from non-REM (nREM) sleep than young adults. Sleep architecture also begins changing in middle age leading to a dramatic decrease in the deepest stage of nREM-slow wave sleep (SWS)-as aging progresses. Other less marked nREM changes include reduced numbers of sleep spindles and K-complexes. In contrast, the amount of REM diminishes only slightly. Both circadian and homeostatic sleep-regulatory processes are affected by aging. Circadian rhythms of temperature, melatonin, and cortisol are phase advanced and their amplitude diminished. An increased number of nocturnal awakenings and diminished daytime sleepiness suggest diminished homeostatic sleep pressure. A variety of endocrine and neuromodulatory changes (e.g., reduced growth hormone and dopamine levels) also accompany healthy aging. Healthy aging is characterized by declines in working memory and new episodic memory performance with relative sparing of semantic memory, recognition memory, and priming. Memory systems impacted by aging are associated with volumetric and functional changes in fronto-striatal circuits along with more limited changes in medial temporal structures (in which larger aging-related changes suggest neuropathology). Cross-sectional studies generally associate poorer sleep quality with poorer neuropsychological functioning. However, paradoxically, older adults appear to be more resistant to the cognitive effects of sleep deprivation, restriction, and fragmentation than younger adults. A new and expanding field examines the interaction between aging and sleep-dependent memory consolidation. Among forms of learning displaying prominent sleep-dependent consolidation in young adults, motor-sequence learning displays loss of sleep-dependent consolidation with aging whereas sleep-dependent consolidation of verbal declarative memory appears spared. Findings suggest that improving sleep through behavioral or pharmacological treatments may enhance cognition and performance in older adults.
健康老龄化的特点是睡眠质量下降，睡眠时间缩短，入睡后觉醒时间增加。老年人比年轻人更容易频繁醒来，而且更容易从非快速眼动（NREM）睡眠中醒来，而不是从快速眼动（REM）睡眠中醒来。睡眠结构也从中年开始改变，导致 NREM-慢波睡眠（SWS）的最深阶段急剧减少，随着年龄的增长。其他不太明显的 NREM 变化包括睡眠纺锤波和 K 复合波数量减少。相比之下，REM 的数量仅略有减少。昼夜节律和稳态睡眠调节过程都会受到衰老的影响。体温、褪黑素和皮质醇的昼夜节律提前相位，并降低其振幅。夜间觉醒次数增加和白天嗜睡减少表明稳态睡眠压力降低。各种内分泌和神经调制变化（例如，生长激素和多巴胺水平降低）也伴随着健康老龄化。健康老龄化的特点是工作记忆和新情景记忆表现下降，而语义记忆、识别记忆和启动相对保留。受衰老影响的记忆系统与额纹状体回路的体积和功能变化有关，而内侧颞叶结构的变化则更为有限（其中较大的与衰老相关的变化表明存在神经病理学）。横断面研究通常将较差的睡眠质量与较差的神经心理功能联系起来。然而，矛盾的是，与年轻人相比，老年人似乎对睡眠剥夺、限制和碎片化的认知影响更有抵抗力。一个新的和不断扩大的领域研究了衰老和睡眠依赖性记忆巩固之间的相互作用。在年轻人中表现出明显的睡眠依赖性巩固的学习形式中，运动序列学习表现出随着年龄的增长而丧失睡眠依赖性巩固，而睡眠依赖性陈述性记忆的巩固似乎得到了保留。研究结果表明，通过行为或药物治疗改善睡眠可能会增强老年人的认知和表现。
