1. Department of Neurology; University of Colorado School of Medicine; Aurora Colorado USA
2. Department of Neurology; Sorlandet Hospital Arendal; Norway
3. Departments of Neurology and Neurosurgery; University of Michigan Medical School; Ann Arbor Michigan USA
4. Department of Neurology; University of North Dakota School of Medicine and Health Science, Department of Neurology, Sanford Health; Fargo North Dakota USA
5. Department of Neurological Sciences; Rush University Medical Center; Chicago Illinois USA
6. Morton and Gloria Shulman Movement Disorders Clinic and the Edmond J. Safra Program in Parkinson's Disease; Toronto Western Hospital; Toronto Ontario Canada
7. Departments of Psychiatry and Neurology; Perelman School of Medicine at the University of Pennsylvania; Philadelphia Pennsylvania USA
8. Parkinson's Disease and Mental Illness Research, Education and Clinical Centers (PADRECC and MIRECC); Philadelphia Veterans Affairs Medical Center; Philadelphia Pennsylvania USA
9. Department of Neurology, Butler Hospital; Alpert Medical School of Brown University; Providence Rhode Island USA