Evaluation of a Brief Survey Instrument for Assessing Subtle Differences in Cognitive Function Among Older Adults.

Abstract

Most measures of cognitive function used in large-scale surveys of older adults have limited ability to detect subtle differences across cognitive domains, and standard clinical instruments are impractical to administer in general surveys. The Montreal Cognitive Assessment (MoCA) can address this need, but has limitations in a survey context. Therefore, we developed a survey adaptation of the MoCA, called the MoCA-SA, and describe its psychometric properties in a large national survey. Using a pretest sample of older adults (n=120), we reduced MoCA administration time by 26%, developed a model to accurately estimate full MoCA scores from the MoCA-SA, and tested the model in an independent clinical sample (n=93). The validated 18-item MoCA-SA was then administered to community-dwelling adults aged 62 to 91 as part of the National Social life Health and Aging Project Wave 2 sample (n=3196). In National Social life Health and Aging Project Wave 2, the MoCA-SA had good internal reliability (Cronbach α=0.76). Using item-response models, survey-adapted items captured a broad range of cognitive abilities and functioned similarly across sex, education, and ethnic groups. Results demonstrate that the MoCA-SA can be administered reliably in a survey setting while preserving sensitivity to a broad range of cognitive abilities and similar performance across demographic subgroups.