The Apathy Evaluation Scale: A Comparison of Subject, Informant, and Clinician Report in Cognitively Normal Elderly and Mild Cognitive Impairment

Abstract

Background: Apathy is a common symptom in Alzheimer’s disease (AD) dementia and mild cognitive impairment (MCI). The Apathy Evaluation Scale (AES) is a promising tool for measuring apathy in early AD. Objective: To compare the AES sub-scales—subject-reported (AES-S), informant-reported (AES-I), and clinician-reported (AES-C)—over time and investigate apathy’s relation to cortical atrophy in MCI and cognitively normal (CN) elderly. Methods: Symptom clusters driving AES scores were identified through factor analysis. Mixed effects longitudinal models were used to assess predictors of AES constructs. Cox proportional hazards models were used to assess which AES constructs predict progression to AD dementia. Finally, we used multivariate regression to evaluate the cross-sectional relationship between AES-C and regional cortical thickness. Results: Across the various mixed effects models, greater apathy was commonly associated with greater years in study, a diagnosis of MCI, and male sex. MCI subjects underreported apathy compared to CN elderly. Of the sub-scales, lower AES-C scores (indicating greater apathy) were most predictive of transition to AD dementia. Lower AES-C scores were also associated with lower inferior temporal cortical thickness. Conclusion: In individuals at risk for AD, the AES-C predicts progression from MCI to AD dementia and lower inferior temporal cortical thickness.