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

OBJECTIVE 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....