School of Psychiatry, University of New South Wales, Sydney, Australia; Black Dog Institute, Sydney, Australia.
School of Psychiatry, University of New South Wales, Sydney, Australia.
J Affect Disord. 2021 Apr 1;284:1-8. doi: 10.1016/j.jad.2021.01.084. Epub 2021 Feb 5.
Depression is associated with cognitive deficits across multiple domains, including working memory. The n-back task, a convenient psychometric tool capable of computerised delivery and concurrent use with neuroimaging, can provide enhanced insight into working memory dysfunction in depression. This meta-analysis sought to investigate the n-back task under varying cognitive load conditions (i.e. different levels of 'n') to clarify the pattern of working memory deficits in depression.
We conducted a systematic review and meta-analysis of studies involving unipolar depressed participants and matched controls utilising the n-back task. Meta-analyses were performed for accuracy and response times at four levels of cognitive load (0-, 1-, 2-, and 3-back).
31 studies (total 1,666 participants) met inclusion criteria and were included for quantitative analyses. Depressed individuals had significantly reduced accuracy compared to controls for 1-, 2-, and 3-back tasks, but not the attentional 0-back task. Likewise, response latencies were prolonged for all task levels (0-, 1-, 2-, and 3-back). Additional meta-regression analyses indicated that participant age and clinical status (i.e. inpatient/outpatient) may exacerbate working memory deficits associated with depression.
Our results indicate high levels of heterogeneity between studies, particularly for response times.
Accuracy impairments were worse at higher levels of n, with the largest effect size obtained on the 2-back task, suggesting deficits to higher executive functions. Response times were consistently prolonged at all cognitive loads in agreement with a pattern of generalised psychomotor retardation.
抑郁症与多个领域的认知缺陷有关，包括工作记忆。n-back 任务是一种方便的心理计量工具，能够进行计算机化交付，并与神经影像学同时使用，可提供对抑郁症患者工作记忆功能障碍的更深入了解。本荟萃分析旨在研究不同认知负荷条件（即不同的“n”水平）下的 n-back 任务，以阐明抑郁症患者工作记忆缺陷的模式。
我们对使用 n-back 任务的涉及单相抑郁患者和匹配对照的研究进行了系统评价和荟萃分析。对四个认知负荷水平（0 次、1 次、2 次和 3 次）的准确性和反应时间进行了荟萃分析。
31 项研究（总计 1666 名参与者）符合纳入标准，并进行了定量分析。与对照组相比，抑郁患者在 1 次、2 次和 3 次任务中准确性显著降低，但在注意力不集中的 0 次任务中没有降低。同样，所有任务水平（0 次、1 次、2 次和 3 次）的反应时均延长。额外的元回归分析表明，参与者年龄和临床状况（即住院/门诊）可能会加剧与抑郁症相关的工作记忆缺陷。
我们的结果表明，研究之间存在高度的异质性，特别是在反应时间方面。
在较高的 n 水平下，准确性的损害更严重，在 2-back 任务中获得的最大效应量，表明存在较高的执行功能缺陷。反应时间在所有认知负荷水平上都持续延长，与普遍的精神运动迟缓模式一致。
