1. Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Standort Witten , Northrine-Westfalia, Germany
2. Witten/Herdecke University Department of Nursing Science, Faculty of Health, , Northrine-Westfalia, Germany
3. Maastricht University Department of Health Services Research, , Limburg, The Netherlands
4. Carl von Ossietzky University Oldenburg Department of Health Services Research, , Lower Saxony, Germany