Psychometric properties of the apathy evaluation scale in patients with Parkinson's disease. - Lueken U; Evens R; Balzer-Geldsetzer M; Baudrexel S; Dodel R; Gräber-Sultan S; Hilker-Roggendorf R; Kalbe E; Kaut O; Mollenhauer B; Reetz K; Schäffer E; et al. (International journal of methods in psychiatric research, 2017)