Department of Neurology, National Neuroscience Institute, Singapore, Singapore.
Duke-NUS Graduate Medical School, Singapore, Singapore.
J Neurol Neurosurg Psychiatry. 2016 Dec;87(12):1375-1383. doi: 10.1136/jnnp-2016-314191. Epub 2016 Oct 19.
Depressive symptoms negatively influence global cognition in the elderly; however, the mechanism of this effect remains unclear.
To investigate whether depressive symptoms influence global cognitive function in patients with mild cognitive impairment (MCI) and mild Alzheimer's disease (AD) by impeding specific neuropsychological abilities and under what conditions this effect might occur.
A sample of 259 participants (104 cognitively normal elderly controls, 66 patients with MCI and 89 patients with mild AD) underwent a comprehensive neuropsychological assessment. Global cognitive impairment was indexed by the composite of Mini-Mental State Examination and Montreal Cognitive Assessment scores and severity of depressive symptoms was measured with the Geriatric Depression Scale (GDS).
Among patients with MCI, greater severity of depressive symptoms was associated with greater global cognitive impairment, with a moderate effect size. A mediation analysis revealed that patients with MCI experiencing depressive symptoms may exhibit global cognitive impairment because their depressive symptoms were reducing their capacity for working memory, episodic memory and non-speed-based executive functions. A moderation analysis indicated that this effect was consistent across age, gender, years of education and APOE-e4 status for working memory and episodic memory, and was observed in patients with MCI older than 65 years for executive functions. In cognitively normal elderly adults and patients with AD, depressive symptoms were not associated with global cognitive impairment.
Depressive symptoms influence global cognitive function in patients with MCI indirectly by reducing mental space, mental flexibility and their capacity for consolidating and retrieving memories. These findings may guide clinicians to better diagnose and manage cognitive impairment in the context of concomitant depressive symptoms.
抑郁症状会对老年人的整体认知能力产生负面影响；然而，这种影响的机制尚不清楚。
通过阻碍特定的神经心理学能力，探讨抑郁症状是否会影响轻度认知障碍（MCI）和轻度阿尔茨海默病（AD）患者的整体认知功能，以及在什么情况下可能会发生这种影响。
一项包含 259 名参与者（104 名认知正常的老年对照组、66 名 MCI 患者和 89 名轻度 AD 患者）的样本接受了全面的神经心理学评估。整体认知障碍由 Mini-Mental State Examination 和 Montreal Cognitive Assessment 评分的综合指标来表示，抑郁症状的严重程度用老年抑郁量表（GDS）来衡量。
在 MCI 患者中，抑郁症状的严重程度与整体认知障碍的严重程度呈正相关，具有中等效应量。中介分析表明，患有 MCI 且伴有抑郁症状的患者可能会出现整体认知障碍，因为他们的抑郁症状会降低他们的工作记忆、情景记忆和非速度依赖的执行功能能力。调节分析表明，这种效应在工作记忆和情景记忆方面，在年龄、性别、受教育年限和 APOE-e4 状态方面在认知正常的老年成年人和 AD 患者中是一致的，并且在执行功能方面在 65 岁以上的 MCI 患者中观察到。在认知正常的老年成年人和 AD 患者中，抑郁症状与整体认知障碍无关。
抑郁症状通过减少心理空间、心理灵活性以及整合和检索记忆的能力，间接地影响 MCI 患者的整体认知功能。这些发现可能为临床医生提供指导，以便在伴有抑郁症状的情况下更好地诊断和管理认知障碍。
