1. Edmond J. Safra Program in Parkinson's Disease, Morton and Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital–UHN, Division of Neurology University of Toronto Toronto Ontario Canada
2. Department of Neurology, Center of Expertise for Parkinson & Movement Disorders, Donders Institute for Brain, Cognition and Behaviour Radboud University Medical Centre Nijmegen The Netherlands
3. Department of Rehabilitation, Center of Expertise for Parkinson & Movement Disorders, Donders Institute for Brain, Cognition and Behaviour Radboud University Medical Centre Nijmegen The Netherlands
4. Sint Maartenskliniek, Department of Rehabilitation Nijmegen The Netherlands