Instrumental Activities of Daily Living in Older Adults with Epilepsy: A Cross-Sectional and Longitudinal Multicenter Study

Objective: Instrumental activities of daily living (IADLs) represent a critical but understudied measure of day-to-day function in persons with epilepsy(PWE). In the multicenter Brain Aging and Cognition in Epilepsy (BrACE) study of PWE aged greater than or equal to 55 years, we examined the proportion, clinical correlates, epilepsy-related predictors, and longitudinal trajectory of IADL impairment. Methods: IADLs were assessed using the Functional Activities Questionnaire (FAQ; range=0 to 30; higher=more impaired); a FAQ greater than or equal to 2 defines MCI-level impairment, and a FAQ greater than or equal to 5 defines dementia-level functional impairment. Multivariable logistic regression identified predictors of baseline function. Global cognition (Montreal Cognitive Assessment [MoCA]), individual cognitive measures, and quality of life (QOL) were compared between the impaired and unimpaired groups. Linear regression evaluated predictors of longitudinal functional decline. Results: Of 57 participants (mean age=66.6 years; female=52.6%), 38.6% (n=22) had MCI-level functional impairment and 17.5% (n=10) had dementia-level functional impairment. In univariate analyses, worse FAQ scores were associated with lower education, higher area deprivation index, early-onset epilepsy (EOE less than 60 years), antiseizure medication polytherapy, and epilepsy localization. In multivariable analysis, temporal lobe epilepsy (OR=4.46, 95% CI=1.09, 21.83,p=0.047), EOE(OR=7.14, 95% CI=1.16, 59.97, p=0.046), and lower education(OR=0.70,95% CI=0.49, 0.93, p=0.025) remained independently associated with baseline MCI-level functional-impairment. Lower education (OR=0.55,95% CI=0.29, 0.84, p=0.021) was the only factor associated with dementia-level IADL-impairment. IADL-impaired participants demonstrated lower verbal memory scores (adjusted p=0.041) and MoCA scores (adjusted p<0.001), particularly in the visuospatial/executive function, attention, and memory subscores, and worse QOL (adjusted p=0.041). IADL impairment was greatest in financially-mediated and memory-dependent tasks. Longitudinally, EOE (beta=7.51,95% CI=1.92, 13.10, p=0.017) and older age(beta=0.38,95% CI=0.12-0.65, p=0.012) predicted greater functional decline. Nearly one-third progressed to significantly worse function over a two-year period, with 15.4% progressing from MCI-level to dementia-level impairment and 15.4% from normal function to MCI-level IADL-impairment. Conclusions: Functional impairment affects ~40% of older PWE, with ~1-in-6 experiencing functional impairment comparable to overt dementias. Temporal lobe localization, EOE, lower education, and poorer cognition are important determinants of baseline functional status. EOE and older age predict accelerated functional decline, suggesting that cumulative disease burden and aging-related processes may drive functional deterioration. These findings provide one of the first epilepsy-specific longitudinal characterizations of IADL impairment and support routine functional assessment in PWE.