1. Center for Human Experimental Therapeutics; University of Rochester Medical Center; Rochester New York USA
2. Northwest Neurological; PLLC, Spokane; Washington, USA
3. Department of Neurology; Johns Hopkins Medicine; Baltimore Maryland USA
4. Radboud University Medical Center, Donders Institute for Brain; Cognition and Behavior, Department of Neurology; Nijmegen the Netherlands
5. Department of Neurology; University of Rochester Medical Center; Rochester New York USA
6. Department of Neurology and Neurobiology; Xuanwu Hospital of Capital Medical University, Beijing Key Laboratory on Parkinson's Disease, Parkinson's Disease Center of Beijing Institute for Brain Disorders; Beijing China
7. Neurology Department; Hospital Universitario; Burgos Spain
8. Rush University Medical Center; Chicago Illinois USA
9. University of Toronto; Division of Neurology, Centre for Movement Disorders; Markham Ontario Canada
10. Department of Neurology; Mayo Clinic; Rochester Minnesota USA
11. Kaiser Permanente Movement Disorders Program; Northern California USA
12. Department of Neurology; University of Pennsylvania; Philadelphia Pennsylvania USA
13. Parkinson's Disease Research, Education and Clinical Center, San Francisco Veterans Affairs Medical Center and Department of Neurology; University of California-San Francisco; San Francisco California USA
14. Department of Medicine; North Tyneside General Hospital; Rake Lane North Shields Tyne and Wear United Kingdom
15. Department of Neurology; Department of Veterans Affairs; Philadelphia Pennsylvania USA