The Florey Institute of Neuroscience and Mental Health.
U.S. Department of Veterans Affairs National Center for Posttraumatic Stress Disorder.
Neuropsychology. 2019 Oct;33(7):964-974. doi: 10.1037/neu0000561. Epub 2019 Aug 1.
Previous studies have shown that paired associate learning (PAL), a type of episodic memory, is impaired in early Alzheimer's disease (AD). Such tasks require that a set of associations (e.g., pattern-location) be learned over several trials, and the objective is to reduce errors with each trial. Currently, the nature and magnitude of impairment and decline on PAL measures in cognitively normal (CN) older adults with elevated levels of beta-amyloid (Aβ+) is unknown.
This study examined PAL errors in Aβ+ and Aβ - CN older adults, both within a single assessment and over time. Participants (210 Aβ - CN, 146 Aβ + CN) from the Australian Imaging, Biomarkers, and Lifestyle (AIBL) study underwent three assessments over 36-months (baseline, and 18- and 36-month follow-ups) using a computerized paired associate learning task (CPAL). Aβ status was determined by positron emission tomography (PET) neuroimaging.
No significant group differences in PAL were evident at baseline. Significant groupxtime interactions were observed, with the Aβ - CN group, but not the Aβ + CN group, evidencing improvement over time (Cohen's d = 0.30 [0.08, 0.51]). Despite this, no group differences were evident at 36-months.
Results suggest that PAL dysfunction is evident over time in Aβ + CNs. This indicates a lack of benefit from repeated exposure to the task over time associated with Aβ+, which is not the case for Aβ - CNs. Further, results suggest that assessing change in Aβ+ related cognition over time, rather than at a single assessment, provides greater understanding of dysfunction in early AD. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
先前的研究表明，成对联想学习（PAL）是一种情景记忆，在早期阿尔茨海默病（AD）中受损。此类任务需要在几次试验中学习一组关联（例如，模式-位置），其目的是在每次试验中减少错误。目前，尚不清楚认知正常（CN）老年人中β-淀粉样蛋白（Aβ+）水平升高的情况下，PAL 测量的损害和下降的性质和程度。
本研究在单次评估和随时间评估中检查了 Aβ+和 Aβ- CN 老年人的 PAL 错误。来自澳大利亚成像、生物标志物和生活方式（AIBL）研究的参与者（210 名 Aβ- CN，146 名 Aβ+ CN）在 36 个月内（基线以及 18 和 36 个月随访）使用计算机化的成对联想学习任务（CPAL）进行了三次评估。Aβ 状态通过正电子发射断层扫描（PET）神经影像学确定。
在基线时，两组在 PAL 方面没有明显差异。观察到显著的组间时间交互作用，Aβ- CN 组，而不是 Aβ+ CN 组，随着时间的推移有所改善（Cohen's d = 0.30 [0.08, 0.51]）。尽管如此，在 36 个月时，两组之间没有差异。
结果表明，Aβ+ CN 随时间推移出现 PAL 功能障碍。这表明，与 Aβ+ 相关的任务随着时间的推移，反复暴露并没有带来益处，而 Aβ- CN 则不是这样。此外，结果表明，随着时间的推移评估 Aβ+相关认知的变化，而不是在单次评估中，更能理解早期 AD 中的功能障碍。（PsycINFO 数据库记录（c）2019 APA，保留所有权利）。
