Measurement equivalence of the NACC UDS neuropsychological battery across race/ethnic groups

Abstract

AbstractBackgroundThe National Alzheimer’s Coordinating Center (NACC) maintains a national database of clinical and cognitive data collected under a standard protocol set by the National Institute on Aging (NIA) called the Uniform Data Set (UDS). Development of factor scores unbiased by race/ethnicity will allow for comparison of other lifestyle and psychosocial factors within the NIA health disparities framework. The present study examined the dimensional structure of the comprehensive neuropsychological test battery and factorial equivalence across racial/ethnic groups.Method43,999 participants (Table 1; Age: Mean = 71.6, Education: Mean = 15.8; Latinx: N = 3549; Asian: N = 1141; Black: N = 5989; White: N = 32832) were assessed at baseline and included in the present study. Clinical status varied from cognitively normal to dementia. The sample was divided into learning and cross‐validation samples; the best fitting model was developed in the learning sample and tested in the cross‐validation sample. Multiple group confirmatory factor analysis (CFA) was used to evaluate measurement equivalence across race/ethnic groups. Measurement invariance models developed in the learning sample were tested in the cross‐validation sample.ResultResults from the full sample identified a best fitting four‐factor model (Figure 1; episodic memory, attention, executive function, language). Multiple group analyses confirmed the presence of metric invariance (Table 2; invariant factor loadings). Results supported partial scalar invariance—all domains had invariant intercepts but also non‐invariant intercepts. Most memory factor indicators had invariant intercepts (5/7). Attention and language had more non‐invariant intercepts. Category fluency, which loaded onto language and executive function factors, was particularly non‐invariant.ConclusionResults showed that the UDS neuropsychological battery measures the same four factors across race/ethnic groups. Crucially, there are important differences in measurement parameters across race/ethnic groups that must be accounted for in studies using these neuropsychological tests as outcomes. The four‐factor model effectively summarizes the comprehensive neuropsychological test battery and could provide a useful tool for studies of cognitive aging and Alzheimer’s disease and related dementias. Importantly, these cognitive factor scores can be used to clarify the influence of lifestyle and psychosocial factors on cognition across these groups.