Apathy and dysfunction in Lewy Body Disease

Abstract

AbstractBackgroundStudies in Alzheimer’s disease and frontal temporal lobe dementia have shown high prevalence and persistence of apathy at different disease stages and its strong association with functional decline. Here we use well‐established methods to examine the relationship between apathy and function in a cohort of well‐characterized patients with Lewy Body Disease (LBD) who had regular assessments over time.MethodSample includes participants in the National Alzheimer’s Coordinating Center Uniform Data Set (NACC‐UDS, 9/2005‐12/2019) who had at baseline (1) cognitive status of mild cognitive impairment (MCI) or dementia, (2) presumed etiologic diagnosis of LBD, and (3) ≥1 follow‐up. Baseline diagnosis of Parkinson’s disease (PD) was assessed. Apathy was identified using clinician judgment. Participants’ function was measured using the Functional Assessment Questionnaire (FAQ). Multivariable linear mixed model (LMM) was used to estimate relationships between apathy, cognitive status (baseline MCI vs dementia), and function over time.ResultThe sample included 339 participants with MCI and 748 with dementia. Average age = 72.7±8.3, 74% male, 86% non‐Hispanic white, 15.4±3.4 years of education, baseline MMSE = 23.7±5.8, with 3.4±1.7 years of follow‐up. Proportion of participants who reported difficulty with function at baseline ranged according to task complexity from 48% (Heating water, making a cup of coffee, turning off stove after use) to 85% (Assembling tax records, business affairs, or papers); with total FAQ = 13.0±9.1. Presence of apathy increased from 52% at baseline to 60% at visit 4. Across all follow‐ups, 24% of the participants were never apathetic, 13.7% had apathy intermittently (<50% of all visits), 28.3% persistently (≥50% of all visits), and 34.0% were apathetic at all visits. LMM estimation results showed that, compared to participants who were never apathetic, FAQ was 3.8±0.8 points higher, i.e., greater dysfunction, at baseline in participants who were always apathetic, and 3.3±0.7 points higher in those who had intermittent/persistent apathy (both p<0.001). Rate of functional decline was 0.41±0.3 points faster each year in those always apathetic compared to never apathetic (p<0.1).ConclusionApathy is highly prevalent in individuals with LBD. Independent of cognitive status, more persistent apathy was strongly associated with worse function.