1. Neurology Clinic, Clinical Center of Serbia; School of Medicine, University of Belgrade; Belgrade Serbia
2. Department of Neurology; Innsbruck Medical University; Austria
3. Neurology Clinic; Clinical Centre of Vojvodina, School of Medicine Novi Sad, University of Novi Sad; Novi Sad Serbia
4. Department for Parkinson's Disease; “Fondazione Ospedale San Camillo,” I.R.C.C.S.; Venice Italy
5. King's College London, Institute of Psychiatry; Department of Psychology; London United Kingdom
6. Institute for Ageing and Health; Newcastle University, Newcastle upon Tyne; United Kingdom
7. Queen Square Brain Bank for Neurological Disorders, Institute of Neurology; University College London; London United Kingdom
8. Dysautonomia Center; Langone Medical Center, New York University; New York USA
9. Univ. de Bordeaux; Institut des Maladies Neurodégénératives; Bordeaux France
10. Department of Neurology; National Hospital Organization Sendai Nishitaga Hospital; Sendai Japan
11. Departments of Psychiatry and Neurology; Perelman School of Medicine at the University of Pennsylvania, and Parkinson's Disease Research, Education and Clinical Center, Philadelphia Veterans Affairs Medical Center; Philadelphia Pennsylvania USA