P1-208: empirical investigation of functional activity in normal aging and mild cognitive impairment: the mayo clinic study of aging

It is generally assumed that persons with mild cognitive impairment (MCI) have little or no functional impairment. Our objective was to conduct an empirical investigation of the functional status in MCI as compared to normal cognitive aging. We conducted a case-control study derived from the population-based Mayo Clinic Study of Aging. The study sample consisted of 2,539 cognitively normal persons and 464 subjects with MCI. We measured functional status with the Functional Assessment Questionnaire (FAQ). The FAQ is a questionnaire with ordinal responses that measures daily functional activities. The higher the FAQ score, the higher the functional impairment. The FAQ was administered to informants by a research nurse or study coordinator. We used a logistic regression model to compute odds ratios (OR) and 95% confidence intervals (95% CI) to compare the FAQ between cognitively normal persons and subjects with MCI. Among cognitively normal persons, the median age (interquartile range [IQR]) was 77.7 (73.8, 82.3) years, 49.1% were females, and the median education was 13 years. Among subjects with MCI, the median age (IQR) for MCI was 81.3 (75.6, 84.3) years, 43.1% were females, and the median education was 12 years. The median (IQR) of FAQ for MCI was 1 (0, 3), and the median (IQR) for cognitively normal persons was 0 (0, 0). The OR (95% CI), that compared the low FAQ scores of the two groups, after adjusting for age, sex, and education, was 1.39 (1.32, 1.47). This means a subject with MCI has a 39% greater odds of having a higher FAQ score than a cognitively normal person. Adjusting for neuropsychiatric symptoms had a negligible impact on the OR (95% CI). As expected, cognitively normal persons as well as MCI subjects scored very low on FAQ indicating normal functional status. This finding gives empirical credence to one of the criterion of MCI, i.e., subjects with MCI have little or no functional impairment.