Background: Apathy, a prevalent and clinically relevant symptom in neurodegenerative disease, is often evaluated by the instrument Apathy Evaluation Scale (AES). However, this instrument has not been translated into Swedish, halting clinical and research efforts. Furthermore, previous studies lack analyses of some basic properties, such as the legitimacy of a total score, or have analysed dimensionality by questionable methods.
Aim: To translate and psychometrically evaluate a Swedish version of the AES.
Method: The AES was translated, and its psychometric properties were tested in the Swedish BioFINDER study, including cognitively well elderly, and subjects with mild cognitive or parkinsonian symptoms. Psychometric analyses were conducted according to classical test theory (CTT) and aimed to resemble those performed in the English original study by Marin et al. in 1991. Dimensionality was additionally analysed on a matrix of polychoric correlations and parallel analyses.
Results: Data indicate that the Swedish AES performs satisfactorily regarding data completeness, scaling assumptions, targeting, and reliability. Principal component analyses (with parallel analysis) of polychoric correlation matrices identified a single component. Convergent and discriminative validity correlations accorded with a priori expectations.
Conclusions: The study provides initial support that this Swedish AES performs similarly to the English original, and exhibits acceptable psychometric properties according to CTT, including supported unidimensionality, and may be adopted for use in clinical and research settings.
Keywords: Apathy; Apathy Evaluation Scale (AES); neurodegenerative disease; neuropsychiatric assessment; psychometrics.