The difference in apathy estimates between the patient and caregiver predicts dementia in individuals with amnestic MCI

Abstract

AbstractBackgroundIn Alzheimer’s disease, apathy is a common behavioral sign (AD). The Apathy Evaluation Scale (AES) is a measure that investigates caregivers' (CG‐AES) and patients' (PT‐AES) perceptions of apathy, and the discrepancy in their evaluations is a proxy for patients' illness unawareness. We aimed to determine whether apathy and awareness of apathy predict dementia development and timing in a cohort study of individuals with amnesic mild cognitive impairment (aMCI).MethodWe acquired two main indices for analysis from the global AES scores of 110 patients with aMCI and their caregivers: i) ‘Apathy,’ the mean of PT‐AES and CG‐AES, and ii) ‘Discrepancy,’ obtained by subtracting CG‐AES from PT‐AES. Patients were seen every six months for three years, or until they developed dementia. The AES indices and the major demographical/neuropsychological variables were filtered for multicollinearity, and the most robust variables were entered into a logistic regression model and survival analyses (Cox regression, log‐rank test of Kaplan‐Meier curves) to estimate which variables predicted the risk and timing of progression, respectively.Result60 patients (54.5%) showed signs of dementia (57 AD) after 6.0‐36.0 months, whereas 28 patients (25.5%) dropped out and 22 patients (20%) were still in an MCI stage. The “Discrepancy” index was a reliable and accurate predictor of the probability of progression (AUC = 0.73) and, after binarization in accordance with a calculated cutoff, of the time to dementia.ConclusionA structured assessment of apathy, both by the patient and by the caregiver, can reveal important details about the likelihood and timing of the transition from aMCI to dementia. The difference between the two estimations serves as a reliable predictor of illness unawareness by patients.