A-04: Functional Impairment in MCI: Memory and Apathy Predict Presence, Executive Function Relates to Severity

Abstract

Objective: Findings regarding the contributions of specific cognitive domains and neuropsychiatric symptoms to functional impairment (FI) in mild cognitive impairment (MCI) are mixed. Additionally, measures of FI are often highly skewed in MCI samples, with many individuals reporting no impairment, complicating standard regression approaches. This study employed a negative binomial hurdle model (NBHM) to examine whether executive function (EF), memory and apathy differentially predict the presence versus severity of FI in mild cognitive impairment (MCI). Method/Data Selection: Participants were N = 2,563 individuals with MCI from the National Alzheimer's Coordinating Center (71.53 ± 7.75 years; 73% White; 54% female; 15.98 ± 2.80 years education). FI was measured using the Functional Activities Questionnaire (FAQ). Composite scores were created for EF and memory. Apathy (NPI-Q item) and depressive symptoms (GDS) were included as behavioral predictors. Due to zero-inflation and over-dispersion of the FAQ scores, an NBHM examined predictors of (1) any impairment (FAQ > 0) and (2) severity among those impaired, adjusting for age, sex, education, global cognition and processing speed. Results/Data Synthesis: Memory (β = -0.20, p < .001) and apathy (β = 1.57, p < .001) predicted the presence of impairment, whereas executive function did not (p = .326). Among impaired individuals, apathy (β = 0.62, p < .001) and memory (β = -0.07, p < .001) remained strong predictors of severity, with executive function showing a modest association (β = -0.10, p = .023). Conclusions: FI in MCI appears to reflect multiple processes, with memory and apathy associated with its presence and executive function more related to severity of impairment.