Psychometric Reliability, Validity, and Generalizability of MoCA in American Indian Adults: The Strong Heart Study

Standardized neuropsychological instruments are used to evaluate cognitive impairment, but few have been psychometrically evaluated in American Indians. We collected Montreal Cognitive Assessment (MoCA) in 403 American Indians 70 to 95 years, as well as age, sex, education, bilingual status, depression symptoms, and other neuropsychological instruments. We evaluated inferences of psychometric validity, including scoring inference using confirmatory factor analysis and structural equation modeling, generalizability inference using reliability coefficient, and extrapolation inference by examining performance across different contexts and substrata. The unidimensional (total score) model had good fit criteria. Internal consistency reliability was high. MoCA scores were positively associated with crystallized cognition (ρ = 0.48, p < .001) and inversely with depression symptoms (ρ = -0.27, p < .001). Significant differences were found by education (d = 0.79, p < .05) depression (d = 0.484, p < .05), and adjudicated cognitive status (p = .0001) strata; however, MoCA was not sensitive or specific in discriminating cognitive impairment from normal cognition (area under the curve <0.5). MoCA scores had psychometric validity in older American Indians, but education and depression are important contextual features for score interpretability. Future research should evaluate cultural or community-specific adaptations, to improve test discriminability in this underserved population.