1. National Center of Epidemiology and CIBERNED; Carlos III Institute of Health; Madrid Spain
2. National Parkinson Foundation Center of Excellence; Department of Neurology; King's College Hospital, and Kings Health Partners; London UK
3. Department of Neurology and Karl Landsteiner Institute for Neuroimmunological and Neurodegenerative Disorders; Danube Hospital; Vienna Austria
4. Department for Parkinson's disease; IRCCS Hospital San Camillo; Venice Italy
5. Department of Neurology; Klinikum-Bremerhaven, Bremerhaven, Germany and Skane University Hospital; Lund Sweden
6. Movement Disorder Clinic; University Hospital of Bispebjerg; Copenhagen Denmark
7. Department of Neurology; University Hospital Cologne; Cologne Germany
8. Movement Disorder Clinic, Beelitz-Heilstätten; Germany
9. Department of Neurology; University Medical Center; Ljubljana Slovenia
10. Department of Neurology; Medical University of Graz; Graz Austria
11. Gailtal-Klinik Hermagor, Neurorehabilitation, Hermagor-Pressegger See; Austria
12. Department of Neurology; University of Dresden; Dresden Germany
13. Department of Neurology; Karolinska Institute; Stockholm Sweden
14. Department of Neurology; University Hospital of Wurzburg; Wurzburg Germany