Longitudinal association of intraindividual variability with cognitive decline and dementia: A meta-analysis.

Intraindividual variability (IIV)-variance in an individual's cognitive performance-may be associated with subsequent cognitive decline and/or conversion to dementia in older adults. This novel measure of cognition encompasses two main operationalizations: inconsistency (IIV-I) and dispersion (IIV-D), referring to variance within or across tasks, respectively. Each operationalization can also be measured with or without covariates. This meta-analytic study explores the association between IIV and subsequent cognitive outcomes regardless of operational definition and measurement approach. Longitudinal studies ( Meta-analytic estimates suggest IIV is associated with subsequent cognitive decline and/or conversion to MCI/dementia ( Cognitive IIV, including both IIV-I and IIV-D operationalizations, appears to be associated with subsequent cognitive decline and/or dementia and may offer a novel indicator of incipient dementia in both clinical and research settings. (PsycInfo Database Record (c) 2021 APA, all rights reserved).