Kremen William S, Elman Jeremy A, Panizzon Matthew S, Eglit Graham M L, Sanderson-Cimino Mark, Williams McKenna E, Lyons Michael J, Franz Carol E
Department of Psychiatry, University of California, San Diego, La Jolla, CA, United States.
Center for Behavior Genetics of Aging, University of California, San Diego, La Jolla, CA, United States.
Front Aging Neurosci. 2022 May 27;14:834765. doi: 10.3389/fnagi.2022.834765. eCollection 2022.
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.
认知储备及相关概念对于衰老相关研究具有重要价值，但由于目前尚无普遍认可的命名法，因此需要对术语进行统一和明确。我们提出了一套关于储备、维持和恢复力概念的新定义，并为适用于认知和大脑的每个概念引入了相应的平行概念。我们对储备和恢复力的定义与这些术语的词典定义相当吻合。我们展示了常用概念定义和操作定义不一致所产生的逻辑/方法学问题。在我们看来，认知储备在概念上应定义为一个人在特定时间点的全部认知资源。智商和教育是认知储备常见的操作定义（通常称为代理指标）的例子。许多研究人员在概念上将认知储备定义为一种特性，即面对衰老或病理状况时，能够在认知方面表现得比预期更好。在统计上，通过调节变量通常为智商或教育的交互作用来证明表现优于预期。结果导致了一种无法调和的情况，即认知储备既是调节变量又是调节效应本身。我们提出的命名法通过将表现优于预期定义为认知恢复力来解决这一逻辑矛盾。因此，按照我们的用法，我们将检验高认知储备赋予更大认知恢复力这一假设。操作定义（所谓的代理指标）不应将可能影响储备的因素（如职业复杂性或参与认知活动）与认知储备本身混为一谈。由于资源可能会随着衰老或病理状况而耗尽，一个人的认知储备水平可能会随时间变化，并且将取决于评估的时间点。因此，除了认知储备和认知恢复力之外，我们引入认知储备维持这一概念，作为与大脑维持相对应的平行概念。然而，如果用教育程度来衡量老年人的储备，就无法评估储备的变化或维持情况。最后，我们讨论了将抵抗力视为恢复力的一个子类别、反向因果关系、使用残差分数来评估在存在某些不利因素的情况下表现优于预期，以及在不同研究中高认知储备与低认知储备的界定。
