Department of Psychology and Neuroscience, Baylor University, Waco, TX.
Department of Communication Sciences and Disorders, Baylor University, Waco, TX.
Sleep. 2019 Jun 11;42(6). doi: 10.1093/sleep/zsz055.
Prospective memory, or remembering to execute future intentions, accounts for half of everyday forgetting in older adults. Sleep intervals benefit prospective memory consolidation in young adults, but it is unknown whether age-related changes in slow wave activity, sleep spindles, and/or rapid eye movement (REM) sleep mediate hypothesized effects of aging on prospective memory consolidation.
After an adaptation night, 76 adults aged 18-84 completed two experimental nights of in-laboratory polysomnography recording. In the evening, participants encoded and practiced a prospective memory task and were tested the next morning. On a counterbalanced night, they encoded and practiced a control task, and were tested the following morning.
Increasing age predicted worse prospective memory consolidation (r = -.34), even when controlling for encoding, speed, and control-task performance (all ps < .05). Frontal delta power, slow oscillations, and spindle density were not related to prospective memory consolidation. REM sleep duration, however, explained significant variance in prospective memory consolidation when controlling for age (∆R2 = .10). Bootstrapping mediation showed that less REM sleep significantly mediated the aging effect on prospective memory consolidation [b = -.0016, SE = 0.0009 (95% confidence interval [CI] = -0.0042 to -0.0004)]. REM sleep continued to mediate 24.29% of the total effect of age on prospective memory after controlling for numerous demographic, cognitive, mental health, and sleep variables.
Age-related variance in REM sleep is informative to how prospective memory consolidation changes with increasing age. Future work should consider how both REM sleep and slow wave activity contribute, perhaps in a sequential or dynamic manner, to preserving cognitive functioning with increasing age.
前瞻性记忆，即记住执行未来的意图，占老年人日常遗忘的一半。在年轻人中，睡眠间隔有利于前瞻性记忆的巩固，但尚不清楚与年龄相关的慢波活动、睡眠纺锤波和/或快速眼动（REM）睡眠的变化是否介导了衰老对前瞻性记忆巩固的假设影响。
在适应夜之后，76 名年龄在 18-84 岁的成年人完成了两个实验室多导睡眠图记录的实验夜。晚上，参与者对前瞻性记忆任务进行编码和练习，并在第二天早上进行测试。在平衡的晚上，他们对控制任务进行编码和练习，并在第二天早上进行测试。
年龄增长预测前瞻性记忆巩固能力下降（r = -.34），即使在控制编码、速度和控制任务表现的情况下也是如此（所有 p <.05）。额部 delta 功率、慢波和纺锤波密度与前瞻性记忆巩固无关。然而，REM 睡眠时间解释了前瞻性记忆巩固中年龄变化的显著差异（∆R2 =.10）。自举中介分析表明，REM 睡眠时间减少显著介导了年龄对前瞻性记忆巩固的影响 [b = -.0016，SE = 0.0009（95%置信区间 [CI] = -0.0042 至 -0.0004）]。在控制了众多人口统计学、认知、心理健康和睡眠变量后，REM 睡眠仍然介导了年龄对前瞻性记忆总效应的 24.29%。
与年龄相关的 REM 睡眠时间的变化有助于了解前瞻性记忆巩固如何随年龄增长而变化。未来的工作应该考虑 REM 睡眠和慢波活动如何以某种顺序或动态方式共同促进认知功能随年龄增长而保持。
