1. Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE) , Witten, North Rhine-Westphalia , Germany
2. Faculty of Health, School of Nursing Science, Witten/Herdecke University , Witten, North Rhine-Westphalia , Germany
3. Diakonie Osnabrück, Stadt und Land GmbH , Osnabrück, Lower Saxony , Germany
4. College of Nursing, Pennsylvania State University , University Park, Pennsylvania , USA
5. Department of Sociology and Gerontology, Miami University , Oxford, Ohio , USA
6. Scripps Gerontology Center, Miami University , Oxford, Ohio , USA