Evaluating the factor structure and construct validity of the NIH toolbox in older adults, with a focus on cognitive normalcy and amnestic mild cognitive impairment: considerations for diversity, including insights from persons over 85 years of age and Black older Americans

Objective: Validated computerized assessments for cognitive functioning are crucial for older individuals and those at risk of cognitive decline. The National Institutes of Health (NIH) Toolbox Cognition Battery (NIHTB-CB) exhibits good construct validity but requires validation in diverse populations and for adults aged 85+. This study uses data from the Assessing Reliable Measurement in Alzheimer's Disease and cognitive Aging study to explore differences in the factor structure of the NIHTB-CB for adults 85 and older, Black participants versus White participants, and those diagnosed as amnestic Mild Cognitive Impairment (aMCI) vs cognitively normal (CN). Method: Subtests from the NACC UDS-3 and NIHTB-CB were administered to 503 community-dwelling Black and White adults ages 55-99 (367 CN; 136 aMCI). Confirmatory factor analyses were used to investigate the original factor structure of NIHTB-CB that forms the basis for NIHTB-CD Index factor scores. Results: Factor analyses for all participants and some participant subsets (aMCI, White, 85+) substantiated the two anticipated factors (Fluid and Crystallized). However, while Black aMCI participants had the expected two-factor structure, for Black CN participants, the List Sorting Working Memory and Picture Sequence tests loaded on the Crystallized factor. Conclusions: Findings provide psychometric support for the NIHTB-CB. Differences in factor structure between Black CN individuals and Black aMCI individuals suggest potential instability across levels of cognitive impairment. Future research should explore changes in NIHTB-CB across diagnoses in different populations.