Department of Neurology, School of Medicine, Washington University in St. Louis.
Department of Psychiatry, School of Medicine, Washington University in St. Louis.
Neuropsychology. 2024 Jan;38(1):69-80. doi: 10.1037/neu0000905. Epub 2023 Apr 20.
Observational studies on aging and Alzheimer's disease (AD) typically focus on mean-level changes in cognitive performance over relatively long periods of time (years or decades). Additionally, some studies have examined how trial-level fluctuations in speeded reaction time are related to both age and AD. The aim of the current project was to describe patterns of variability across repeated days of testing as a function of AD risk in cognitively normal older adults.
The current project examined the performance of the Ambulatory Research in Cognition (ARC) smartphone application, a high-frequency remote cognitive assessment paradigm, that administers brief tests of episodic memory, spatial working memory, and processing speed. Bayesian mixed-effects location scale models were used to explore differences in mean cognitive performance and intraindividual variability across 28 repeated sessions over a 1-week assessment interval as function of age and genetic risk of AD, specifically the presence of at least one apolipoprotein E (APOE) ε4 allele.
Mean performance on processing speed and working memory was negatively related to age and APOE status. More importantly, e4 carriers exhibited increased session-level variability on a test of processing speed compared to noncarriers. Age and education did not consistently relate to cognitive variability, contrary to expectations.
Preclinical AD risk, defined as possessing at least one APOE ε4 allele, is not only associated with mean-level performance differences, but also with increases in variability across repeated testing occasions particularly on a test of processing speed. Thus, cognitive variability may serve as an additional and important indicator of AD risk. (PsycInfo Database Record (c) 2023 APA, all rights reserved).
关于衰老和阿尔茨海默病（AD）的观察性研究通常侧重于认知表现的平均水平随时间的变化（数年或数十年）。此外，一些研究还探讨了速度反应时间的试验水平波动与年龄和 AD 之间的关系。本项目的目的是描述认知正常的老年人中，随着 AD 风险的增加，在重复多天的测试中变异性的模式。
本项目检查了 Ambulatory Research in Cognition（ARC）智能手机应用程序的性能，这是一种高频远程认知评估范式，它对情景记忆、空间工作记忆和处理速度进行简短测试。贝叶斯混合效应位置尺度模型用于探索在 1 周评估间隔内 28 次重复测试中，平均认知表现和个体内变异性的差异，作为年龄和 AD 遗传风险（特别是至少存在一个载脂蛋白 E（APOE）ε4 等位基因）的函数。
处理速度和工作记忆的平均表现与年龄和 APOE 状态呈负相关。更重要的是，与非携带者相比，e4 携带者在处理速度测试中的测试水平变异性增加。与预期相反，年龄和教育程度并不总是与认知变异性相关。
定义为至少携带一个 APOE ε4 等位基因的临床前 AD 风险不仅与平均水平的表现差异有关，而且与在重复测试中变异性的增加有关，特别是在处理速度测试中。因此，认知变异性可能是 AD 风险的另一个重要指标。（PsycInfo 数据库记录（c）2023 APA，保留所有权利）。
