1. National Parkinson Foundation International Centre of Excellence, King's College Hospital NHS Foundation Trust, London, UK
2. National Center of Epidemiology and CIBERNED, Carlos III Institute of Health, Madrid, Spain
3. Department of Neurology, Forth Valley Royal Hospital, NHS Forth Valley
4. Anne Rowling Regenerative Neurology Clinic, University of Edinburgh, UK
5. Division of Clinical Neurosciences, Western General Hospital, Edinburgh
6. Salford Royal NHS Foundation Trust, Manchester, UK
7. United Lincolnshire Hospitals NHS Trust, Lincoln, UK
8. King's College London, UK