The Cognitive Abilities Screening Instrument (CASI): Data from a cohort of 2524 cognitively intact elderly

Objectives. To describe the effects of age and education for the Cognitive Abilities Screening Instrument (CASI), a 25-item test of cognitive function. Design. Cross-sectional descriptive study of the initial enrollment in a community-based prospective cohort study. Participants. A total of 2524 cognitively intact older adults over age 65 who were members of a major health maintenance organization, and who consented to participate in a longitudinal study. Measurements. Summary scores for the CASI are given in the form of mean, median and percentile distributions specific for age and educational level. Results. Based upon maximum likelihood analyses, age and education were significant (p < 0.0001) predictors of total CASI score. Increased age and lower education were associated with a lower CASI score, as well as an increased spread in score distribution. Gender was also significantly related (p < 0.01) to total CASI, with women having a slightly higher distribution of scores. Mean total scores ranged from CASI = 82.2 (SD = 9.0) in subjects aged 90-95 who had less than a high school degree to CASI = 94.8 (SD = 3.8) in subjects aged 65-69 with at least a high school education. Conclusions. Like most cognitive screening instruments, performance on the CASI in non-demented persons is influenced by age and education. The reference values for 5-year age categories described in this article should be useful for clinicians and research investigators when using the CASI as a measure of cognitive function.