Construct validation of NIH Toolbox Cognition Battery premorbid cognitive functioning scores in Black and White older Americans with and without mild cognitive impairment.

Objective: Valid estimates of premorbid cognitive functioning (PMIQ) are crucial for the assessment of older adults at risk for Alzheimer's disease. We investigated the relationship between the NIH Toolbox-Cognition Battery's (NIHTB-CB) Oral Reading Recognition (ORR) subtest and Wechsler Test of Adult Reading scores (WTAR, convergent validity). We also compared ORR to NIHTB-CB Flanker scores, where null relationships were expected (discriminant validity).

Methods: The WTAR and NIHTB-CB were administered to 130 cognitively normal (CN) and 113 participants with mild cognitive impairment (MCI). Participants were community-dwelling, older Black and White adults, ages 55-88 years. Data analysis used uncorrected standard scores and Bayesian bivariate correlations. Supplemental materials include intraclass correlations.

Results: ORR and WTAR scores were strongly positively associated, while ORR and Flanker scores were unrelated. This pattern held when restricting analyses to the two cognitive status groups, the two racial groups, and the four race-by-diagnosis subgroups.

Conclusion: The findings demonstrate convergent and discriminant validity and support NIHTB-CB ORR scores as valid estimates of scores on a PMIQ measure in older Black and White adults with and without MCI.