Affiliations: [a] Department of Psychology, University of Edinburgh, Edinburgh, UK
| [b] Anne Rowling Regenerative Neurology Clinic, University of Edinburgh, Edinburgh, UK
| [c] Alzheimer Scotland Dementia Research Centre, University of Edinburgh, Edinburgh, UK
| [d] Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, UK
| [e] Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, Edinburgh, UK
Correspondence:
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Correspondence to: Ratko Radakovic, University of Edinburgh, Department of Psychology, 7 George Square, Edinburgh, EH8 9JZ, UK. Tel.: +441316511303; E-mails: r.radakovic@ed.ac.uk; radakovic.ratko@gmail.com.
Abstract: Background:Apathy is a complex multidimensional syndrome frequently reported in Alzheimer’s disease (AD) and is associated with impaired awareness. Here we present a psychometrically robust method to profile apathy in AD. Objectives:To determine the validity and reliability of a multidimensional apathy measure, the Dimensional Apathy Scale (DAS), and explore the apathy subtype profile and its associations in AD. Methods:102 people with AD and 55 healthy controls were recruited. Participants completed the DAS, the Apathy Evaluation Scale (AES), Geriatric Depression Short form (GDS-15), and Lawton Instrumental Activities of Daily Living (LIADL). Psychometric properties of the DAS were determined. AD-Control comparison was performed to explore group differences on the DAS. Latent Class Analysis (LCA) was used to explore the profile of apathy in AD. Results:The DAS had a good to excellent Cronbach’s standardized alpha (self-rated = 0.85, informant/carer-rated = 0.93) and good convergent and divergent validity against standard apathy (AES) and depression (GDS-15) measures. Group comparison showed people with AD were significantly higher for all apathy subtypes than controls (p < 0.001), and lacking in awareness over all apathy subtype deficits. LCA showed three distinct AD subgroups, with 42.2% in the Executive-Initiation apathy, 28.4% in the Global apathy, and 29.4% in the Minimal apathy group. Conclusions:The DAS is a psychometrically robust method of assessing multidimensional apathy in AD. The apathy profiles in AD are heterogeneous, with additional specific impairments relating to awareness dependent on apathy subtype.
