Cognitive intra-individual variability as an emerging measure of neuropsychological inference: A narrative review of its history, methodology, empirical support, future directions, and recommendations for best practices

IIV reliably differentiates clinical populations from healthy groups and predicts disease progression, everyday functioning, and mortality. Questions pertaining to the optimal methodology for IIV, its cognitive architecture, and its incremental validity remain unanswered. The evidence suggests that IIV has the potential to be used as a method of neuropsychological inference in traditional neuropsychological assessment and with ecological momentary assessments. We conclude this review with recommendations for best practices for employing IIV measures in research.