Kraal A Zarina, Massimo Lauren, Fletcher Evan, Carrión Carmen I, Medina Luis D, Mungas Dan, Gavett Brandon E, Farias Sarah Tomazewski
Department of Psychology, University of Michigan.
Department of Neurology, University of Pennsylvania.
Neuropsychology. 2021 Jan;35(1):19-32. doi: 10.1037/neu0000705.
Cognitive reserve is a concept that explains individual differences in resilience to brain pathology and susceptibility to poor late-life cognitive outcomes. We evaluate the analogous concept of "Functional Reserve," defined as the difference between observed functional abilities and those predicted by brain structure, cognitive performance, and demographics. This study aims to validate the construct of functional reserve by testing its utility in predicting clinical outcomes and exploring its predictors.
Longitudinal data collected annually for up to 7 years from 1,084 older adults (ndementia = 163; nMCI = 333; nCN = 523) were analyzed. Functional reserve was operationalized as the residual variance in the Lawton-Brody Instrumental Activities of Daily Living (IADL) Scale after accounting for demographics (sex/gender, race, ethnicity, education), neuropathology (gray matter, hippocampal, and white matter hyperintensity volumes), and cognition (executive function, verbal episodic memory, semantic memory, and spatial function). Structural equation models estimated (a) functional reserve's associations with 7-year changes in clinical diagnosis and disease severity and (b) predictors of functional reserve.
Functional reserve was lower in dementia versus cognitively normal individuals. Higher baseline functional reserve was associated with lower concurrent dementia severity and slower clinical progression and attenuated the association of cognition with concurrent dementia severity. Physical function and apathy were the strongest predictors of functional reserve.
Results provide preliminary validation of functional reserve for explaining individual differences in susceptibility to IADL dysfunction independent of neuropathology, cognition, and demographics. Physical functioning and apathy are promising modifiable intervention targets to enhance functional reserve in the context of brain atrophy and cognitive decline. (PsycInfo Database Record (c) 2021 APA, all rights reserved).
认知储备是一个解释个体对脑部病变的恢复力以及晚年认知不良结果易感性差异的概念。我们评估了“功能储备”这一类似概念，其定义为观察到的功能能力与由脑结构、认知表现和人口统计学因素预测的功能能力之间的差异。本研究旨在通过测试其在预测临床结果方面的效用并探索其预测因素来验证功能储备这一概念。
分析了从1084名老年人（痴呆症患者n = 163；轻度认知障碍患者n = 333；认知正常者n = 523）那里每年收集长达7年的纵向数据。在考虑了人口统计学因素（性别、种族、民族、教育程度）、神经病理学因素（灰质、海马体和白质高信号体积）以及认知因素（执行功能、言语情景记忆、语义记忆和空间功能）之后，将功能储备定义为Lawton - Brody日常生活活动能力量表（IADL）中的残差方差。结构方程模型估计了（a）功能储备与临床诊断和疾病严重程度的7年变化之间的关联，以及（b）功能储备的预测因素。
与认知正常的个体相比，痴呆症患者的功能储备较低。较高的基线功能储备与较低的同期痴呆症严重程度、较慢的临床进展相关，并减弱了认知与同期痴呆症严重程度之间的关联。身体功能和冷漠是功能储备最强的预测因素。
研究结果为功能储备提供了初步验证，以解释在独立于神经病理学、认知和人口统计学因素的情况下，个体对IADL功能障碍易感性的差异。在脑萎缩和认知衰退的背景下，身体功能和冷漠是增强功能储备的有前景的可改变干预目标。（PsycInfo数据库记录（c）2021美国心理学会，保留所有权利）
