1 Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA.
2 Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey, USA.
3 Edmond J. Safra Program in Parkinson's Disease, Rossy Progressive Supranuclear Palsy Centre, Movement Disorders Clinic, Krembil Brain Institute, Toronto Western Hospital, University Health Network and Division of Neurology, University of Toronto, Toronto, Ontario, Canada.
4 Movement Disorder Program, Department of Neurology, University of Chicago Medicine, Chicago, Illinois, USA.
5 Department of Neurology, Oregon Health and Science University, Portland, Oregon, USA.
6 James J. and Joan A. Gardner Family Center for Parkinson's Disease and Movement Disorders, Department of Neurology, University of Cincinnati, Cincinnati, Ohio, USA.
7 Tanz Centre for Research in Neurodegenerative Diseases, Rossy Progressive Supranuclear Palsy Centre, University of Toronto, Krembil Brain Institute, University Health Network, Toronto, Ontario, Canada.
8 Struthers Parkinson's Center, HealthPartners, Golden Valley, Minnesota, USA.
9 University of Florida College of Medicine Center for Movement Disorders and Neurorestoration, Department of Neurology, Gainesville, Florida, USA.
10 University of Rochester, Neurology, Rochester, New York, USA.
11 Department of Neurology, Medical University of South Carolina, Charleston, South Carolina, USA.
12 Parkinson's and Movement Disorders Center, Neurological Institute, University Hospitals Cleveland Medical Center and Case Western Reserve University, Cleveland, Ohio, USA.
13 Johns Hopkins University School of Medicine, Department of Neurology, Baltimore, Maryland, USA.