1. Department of Human Neurosciences Sapienza University of Rome Rome Italy
2. IRCCS Neuromed Pozzilli Italy
3. Gardner Family Center for Parkinson's Disease and Movement Disorders, Department of Neurology University of Cincinnati Cincinnati Ohio USA
4. Edmond J. Safra Program in Parkinson's Disease, Morton and Gloria Shulman Movement Disorders Clinic Toronto Western Hospital, UHN Toronto Ontario Canada
5. Division of Neurology University of Toronto Toronto Ontario Canada
6. Krembil Brain Institute Toronto Ontario Canada
7. Human Motor Control Section National Institute of Neurological Disorders and Stroke, National Institutes of Health Bethesda Maryland USA