Greater Cognitive Intraindividual Variability Predicts Faster Decline in Everyday Functioning: Moderating Effects of Amyloid Status and APOE Genotype

Greater cognitive IIV was associated with faster functional decline, particularly among individuals who are Aβ+ or APOE ε4 carriers. Findings suggest that IIV may be a sensitive marker of brain changes and functional decline, offering added utility above and beyond conventional AD risk factors including age and gender as well as mean level of cognitive performance. Future research is needed to determine how to best operationalize IIV and establish reliability and validity of IIV in populations who better represent older adults who may be at greater risk for cognitive decline.