Center for Brain Disorder and Cognitive Science, Shenzhen University, Shenzhen, China.
Center for Neuroimaging, Shenzhen Institute of Neuroscience, Shenzhen, China.
J Alzheimers Dis. 2020;76(4):1637-1650. doi: 10.3233/JAD-190990.
Both sleep quality and depression could affect cognitive performance in older adults. Previous studies have suggested that there are bi-directional relationships between sleep quality and depression. Possibly, the influence of sleep quality on cognition is partly mediated by depression, and vice versa.
We aimed to assess the mediation effects of sleep quality and depression on each other's relationship with various cognitive functions in non-demented older adults.
Correlations were examined among sleep quality indices, depressive severity score, and five cognitive functions in 206 cognitively normal (CN) older adults and all participants that included these CN and 40 mild cognitive impairment (MCI) individuals. We then analyzed the mediation effects for the significant cognitive correlations of sleep disturbance and depression using the bias-corrected Bootstrap method in the two populations.
Both sleep disturbance and depression were significantly correlated with memory recall and processing speed. In CN, depression could mediate the relationships of sleep disturbance with both cognitive functions, while sleep disturbance could only mediate the relationship of depression with processing speed, but not memory recall. However, in all participants, sleep disturbance could mediate the relationships of depression with both cognitive functions.
Different mediation effects in the two models in CN older adults might suggest differential mechanisms underlying the pathways from sleep disturbance and depression to various cognitive functions. The mediation results in all participants might indicate that the mechanisms underlying the pathways from sleep disturbance and depression to memory recall were different between MCI and CN older adults.
睡眠质量和抑郁都会影响老年人的认知表现。先前的研究表明，睡眠质量和抑郁之间存在双向关系。可能睡眠质量对认知的影响部分是通过抑郁来介导的，反之亦然。
我们旨在评估睡眠质量和抑郁对彼此与认知功能的关系的中介作用，这些认知功能在认知正常的老年人中。
我们检查了 206 名认知正常（CN）老年人和所有参与者（包括这些 CN 和 40 名轻度认知障碍（MCI）个体）的睡眠质量指数、抑郁严重程度评分和五种认知功能之间的相关性。然后，我们使用偏置校正的自举方法分析了这两个群体中与睡眠障碍和抑郁相关的显著认知相关性的中介效应。
睡眠障碍和抑郁均与记忆回忆和处理速度显著相关。在 CN 中，抑郁可以中介睡眠障碍与这两种认知功能的关系，而睡眠障碍只能中介抑郁与处理速度的关系，而不是记忆回忆。然而，在所有参与者中，睡眠障碍可以中介抑郁与这两种认知功能的关系。
CN 老年人中两个模型的不同中介效应可能表明睡眠障碍和抑郁与各种认知功能之间的途径存在不同的机制。所有参与者的中介结果可能表明，MCI 和 CN 老年人中，记忆回忆与睡眠障碍和抑郁之间的途径的机制不同。
