1. Department of Neurology Montreal Neurological Institute, McGill University Montreal Quebec Canada
2. Departments of Psychiatry and Neurology, Perelman School of Medicine at the University of Pennsylvania; Parkinson's Disease Research, Education and Clinical Center (PADRECC) Philadelphia Veterans Affairs Medical Center Philadelphia Pennsylvania USA
3. Feinberg School of Medicine Northwestern University Chicago Illinois USA
4. Movement Disorders Clinic National Institute of Neurology and Neurosurgery Mexico City Mexico
5. Department of Psychiatry Maastricht University Medical Center Maastricht The Netherlands
6. Nuffield Department of Clinical Neurosciences, Neurology Department Oxford University and John Radcliffe Hospital Oxford United Kingdom
7. James J. and Joan A. Gardner Family Center for Parkinson's Disease and Movement Disorders, Department of Neurology University of Cincinnati Cincinnati Ohio USA
8. Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana”, Neuroscience Section University of Salerno Baronissi Italy
9. Neurology and Movement Disorders Department University of Lille, Inserm, Lille Neurosciences and Cognition, CHU‐Lille Lille France
10. Departments of Radiology and Neurology University of Michigan, University of Michigan Udall Center, Ann Arbor VAMC Ann Arbor Michigan USA
11. Department of Neurology Christian‐Albrechts‐University Kiel Germany
12. Division of Neurology, Department of Medicine University of Ottawa, The University of Ottawa Brain and Research Institute Ottawa Ontario Canada
13. Parkinson's Disease and Movement Disorders Clinic The Ottawa Hospital, The Ottawa Hospital Research Institute Ottawa Ontario Canada
14. Edmond J. Safra Program in Parkinson's Disease and the Morton and Gloria Shulman Movement Disorders Clinic Toronto Western Hospital, University Health Network Toronto Ontario Canada