1. Parkinson's Disease and Movement Disorders Center, Division of Neurology, Department of Medicine, The Ottawa Hospital Research Institute; University of Ottawa Brain and Mind Institute; Ottawa Canada
2. Department of Physical Medicine and Rehabilitation; University of Michigan; Ann Arbor Michigan USA
3. School of Psychology and Clinical Language Sciences; University of Reading; Reading UK
4. Swiss HD Center, NeuroZentrumSiloah and Department of Neurology; University of Bern; Bern Switzerland
5. Department of Neurology; Wake Forest School of Medicine; Winston Salem North Carolina USA
6. Krembil Research Institute, University Health Network and Institute of Health Policy, Management and Evaluation and Rehabilitation Institute; University of Toronto; Toronto Canada
7. Centre for Trials Research; Cardiff University; Wales UK
8. Department of Biobehavioral Sciences, Teachers College; Columbia University; New York, NY USA
9. Huntington's Disease Centre, Institute of Neurology; University College London; London UK
10. Clinical Pharmacology Unit, Instituto de Medicina Molecular; Lisbon Portugal
11. Laboratory of Clinical Pharmacology and Therapeutics, Faculty of Medicine; University of Lisbon; Lisbon Portugal
12. CHDI Foundation/CHDI Management; Princeton New Jersey USA
13. Department of Neurological Sciences; Rush University Medical Center; Chicago Illinois USA
14. Department of Neurology; Hospital Universitário Hermanos Yagüe; Burgos Spain
15. National Center of Epidemiology and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) Carlos III Institute of Health; Madrid Spain