Instrumental activities of daily living in older adults with epilepsy: A cross-sectional and longitudinal multicenter...

Instrumental activities of daily living (IADLs) represent a critical but understudied measure of day-to-day function in people with epilepsy (PWE). In the multicenter Brain Aging and Cognition in Epilepsy (BrACE) study of PWE ≥55 years of age, we examined the proportion, clinical correlates, epilepsy-related predictors, and longitudinal trajectory of IADL impairment.

IADLs were assessed using the Functional Activities Questionnaire (FAQ; range = 0-30; higher = more impaired); FAQ ≥ 2 defines mild cognitive impairment (MCI)-level impairment and FAQ ≥ 5 dementia-level functional impairment. Multivariable Firth penalized logistic regression identified factors associated with baseline functional impairment. Global cognition (Montreal Cognitive Assessment [MoCA]), individual cognitive measures, and quality of life (QOL) were compared between the impaired and unimpaired groups. Exploratory linear regression evaluated factors associated with longitudinal functional decline.

Of 57 participants (mean age ± SD = 66.6 ± 7.2 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; <60 years), anti-seizure medication polytherapy, and epilepsy localization (all p's < .05). In multivariable analysis, temporal lobe epilepsy (odds ratio [OR] = 3.73, 95% confidence interval [CI] = 1.02-16.12, p = .047), EOE (OR = 6.91, 95% CI = 1.36-46.37, p = .019), and lower education (OR = 0.69, 95% CI = 0.51-0.90,p = .004) remained independently associated with baseline MCI-level functional impairment. Lower education (OR = 0.62, 95% CI = 0.37-0.87, p = .004) was the only factor associated with dementia-level IADL impairment. IADL-impaired participants demonstrated lower verbal memory scores (adjusted-p = .042) and MoCA (adjusted-p = .006), particularly in visuospatial/executive function, attention, and memory subscores, and worse QOL (adjusted-p = .042). IADL impairment was greatest in financially-mediated and memory-dependent tasks. Longitudinally, EOE (p = .017) and older age (p = .012) were associated with greater functional decline. Four of 13 participants (approximately one-third) progressed to significantly worse function over a 2-year period, with two (15.4%) progressing from MCI-level to dementia-level impairment and two (15.4%) from normal function to MCI-level IADL impairment.

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. Exploratory longitudinal analyses has suggested that EOE and older age were associated with accelerated functional decline, although these findings require confirmation in larger cohorts. These findings provide one of the first epilepsy-specific characterizations of IADL impairment and support routine functional assessment in PWE.