Differential cued-Stroop performance in cognitively asymptomatic older adults with biomarker-identified risk for Alzheimer’s disease: A pilot study

Background: There exists a need for more sensitive measures capable of detecting subtle cognitive decline due to Alzheimer’s disease. Objective: To advance the literature in Alzheimer’s disease by demonstrating that performance on a cued-Stroop task is impacted by preclinical Alzheimer’s disease neuropathology. Method: Twenty-nine cognitively asymptomatic older adults completed a computerized, cued-Stroop task in which accuracy rates and intraindividual variability in reaction times were the outcomes of interest. Cerebrospinal fluid biomarkers of Aβ ₄₂ and tau were measured and participants were then grouped according to a published p-tau/Aβ ₄₂ cutoff reflecting risk for Alzheimer’s disease (preclinical Alzheimer’s disease = 14; control = 15). Results: ANOVAs indicated that accuracy rates did not differ between the groups but 4-second delay incongruent color-naming Stroop coefficient of variation reaction times were higher in the preclinical Alzheimer’s disease group compared to the control group, reflecting increased within-person variability. Moreover, partial correlations showed no relationships between cerebrospinal fluid biomarkers and accuracy rates. However, increases in coefficient of variation reaction times correlated with decreased Aβ ₄₂ and increases in p-tau and the p-tau/Aβ ₄₂ ratio. Conclusion: Results supported the ability of the computerized, cued-Stroop task to detect subtle Alzheimer’s disease neuropathology using a small cohort of cognitively asymptomatic older adults. The ongoing measurement of cued-Stroop coefficient of variation reaction times has both scientific and clinical utility in preclinical Alzheimer’s disease.