Cognitive Reserve and Related Constructs: A Unified Framework Across Cognitive and Brain Dimensions of Aging

Abstract

Cognitive reserve and related constructs are valuable for aging-related research, but consistency and clarification of terms is needed as there is still no universally agreed upon nomenclature. We propose a new set of definitions for the concepts of reserve, maintenance, and resilience, and we invoke parallel concepts for each that are applicable to cognition and to brain. Our definitions of reserve and resilience correspond reasonably well to dictionary definitions of these terms. We demonstrate logical/methodological problems that arise from incongruence between commonly used conceptual and operational definitions. In our view, cognitive reserve should be defined conceptually as one’s total cognitive resources at a given point in time. IQ and education are examples of common operational definitions (often referred to as proxies) of cognitive reserve. Many researchers define cognitive reserve conceptually as a property that allows for performing better than expected cognitively in the face of aging or pathology. Performing better than expected is demonstrated statistically by interactions in which the moderator is typically IQ or education. The result is an irreconcilable situation in which cognitive reserve is both the moderator and the moderation effect itself. Our proposed nomenclature resolves this logical inconsistency by defining performing better than expected as cognitive resilience. Thus, in our usage, we would test the hypothesis that high cognitive reserve confers greater cognitive resilience. Operational definitions (so-called proxies) should not conflate factors that may influence reserve—such as occupational complexity or engagement in cognitive activities—with cognitive reserve itself. Because resources may be depleted with aging or pathology, one’s level of cognitive reserve may change over time and will be dependent on when assessment takes place. Therefore, in addition to cognitive reserve and cognitive resilience, we introduce maintenance of cognitive reserve as a parallel to brain maintenance. If, however, education is the measure of reserve in older adults, it precludes assessing change or maintenance of reserve. Finally, we discuss consideration of resistance as a subcategory of resilience, reverse causation, use of residual scores to assess performing better than expected given some adverse factor, and what constitutes high vs. low cognitive reserve across different studies.

The neuropsychology of healthy aging: the positive context of the University of the Third Age during the COVID-19 pandemic

“…A healthy lifestyle that includes cognitive, social, and physical activities was positively correlated with global cognition 18 , which was achieved through informal learning programs and activities such as the University of the Third Age (U3A) 19 . The combination of positive life experiences such as education and participation in cognitive and socially stimulating leisure activities is thought to increase the effectiveness of cognitive processing in aging individuals, also referred to as cognitive reserve (CR) 20 . It improves cognitive function in healthy aging subjects; in particular, CR has been associated with global cognition 21 and has been reported to enhance executive function and attention 22 , 23 .…”

Quantifying Brain and Cognitive Maintenance as Key Indicators for Sustainable Cognitive Aging: Insights from the UK Biobank

“…CR can be metaphorically envisioned as software that executes computations in the brain and is shaped by diverse aspects of life experience [12]. This means that cognitive engagement, social interaction, and physical exercise throughout life can all contribute to building and maintaining CR, BM [13], and CM [14].…”

“…Cabeza et al [15] highlighted the clear relationship between reserve and maintenance but emphasized their distinct features: reserve enhances and augments resources, while maintenance preserves these resources through constant recovery and repair. Kremen et al [14] suggested that reserve and maintenance are two parallel concepts, and the lack of reference to CM is due to the common use of static CR proxies, such as education, which do not allow for the examination of changes in CR. To promote more consistent and rigorous research, the reserve, resilience, and protective factors professional interest area, established under the auspices of the Alzheimer's Association, formed a white paper workgroup to develop consensus definitions for BR, CR, and BM [12].…”

A bidirectional relationship between cognitive reserve and cognition among older adults in a rural Chinese community: a cross-lagged design

“…However, it remains unclear whether a reverse association is established. A perspective acknowledges that individuals with higher cognitive reserves may be more likely to actively seek out and participate in activities that stimulate their cognitive abilities ( Kremen et al, 2022 ). Moreover, some studies have indirectly suggested that cognitive functioning might impact on cognitive reserve ( Aartsen et al, 2002 ; Jones et al, 2011 ).…”