Objective: Alzheimer's disease (AD) causes increasing cognitive and functional impairments, yet if and how cognition impacts functioning remains unclear. Here, we assessed the relationship between cognitive domains and everyday functioning in participants with AD.
Method: In this cross-sectional study, we included participants with biomarker-confirmed AD with subjective cognitive decline (SCD), mild cognitive impairment (MCI), or dementia from the Amsterdam Dementia Cohort. Cognition was assessed with a standardized neuropsychological test battery divided into domains using exploratory factor analysis (EFA). These were used as input for structural equation modeling (SEM) to calculate the unique associations with everyday functioning, measured with the well-validated study partner-based Amsterdam Instrumental Activities of Daily Living Questionnaire (A-IADL-Q). Model fit of the SEM and its associations were described in standardized paths (std.lv).
Results: A total of 613 participants were included, mean age ± SD = 65 ± 8 years, 310(51%) female, with a mean A-IADL-Q of 50.2 ± 9.3. The majority had a diagnosis of dementia (n = 443, 72%), followed by MCI (n = 100, 16%) and SCD (n = 70, 11%). SEM analysis, χ²(137, N = 613) = 1072.17, p < .001, showed that, of the four cognitive domains identified using EFA, "memory" (std.lv = 0.33) and "visual attention, mental flexibility, and visuoconstruction" (std.lv = 0.29) were related to A-IADL-Q, while "working memory, shifting, fluency, and inhibition" and "naming" were not.
Conclusions: Lower performance in memory and visual attention, mental flexibility, and visuoconstruction was related to more difficulties in everyday functioning. A better understanding of how cognition relates to everyday functioning has important implications for personalized care strategies and trial outcomes. (PsycInfo Database Record (c) 2025 APA, all rights reserved).