A Zarina Kraal1, Lauren Massimo2, Evan Fletcher3, Carmen I Carrión4, Luis D Medina5, Dan Mungas3, Brandon E Gavett6, Sarah Tomazewski Farias3. 1. Department of Psychology, University of Michigan. 2. Department of Neurology, University of Pennsylvania. 3. Department of Neurology, University of California, Davis. 4. Department of Neurology, School of Medicine, Yale University. 5. Department of Psychology, University of Houston. 6. Department of Psychological Science, University of Western Australia.
Abstract
OBJECTIVE: 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. METHOD: 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. RESULTS: 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. CONCLUSIONS: 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).
OBJECTIVE: 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. METHOD: 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. RESULTS: 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. CONCLUSIONS: 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).
Authors: Rochelle E Tractenberg; Myron F Weiner; Jeffrey L Cummings; Marian B Patterson; Leon J Thal Journal: J Neuropsychiatry Clin Neurosci Date: 2005 Impact factor: 2.198
Authors: Charles DeCarli; Bruce R Reed; William Jagust; Oliver Martinez; Mario Ortega; Dan Mungas Journal: Alzheimer Dis Assoc Disord Date: 2008 Oct-Dec Impact factor: 2.703