1. The Norwegian Centre for Movement Disorders, Stavanger University Hospital, Stavanger, Norway
2. Centre of Behavioral Research, University of Stavanger, Stavanger, Norway
3. Department of Neurology, Stavanger University Hospital, Stavanger, Norway
4. The Norwegian Multiple Sclerosis Competence Centre, Department of Neurology, Haukeland University Hospital, Bergen, Norway; Department of Clinical Medicine, Section of Neurology, University of Bergen, Bergen, Norway
5. The Norwegian Centre for Movement Disorders, Stavanger University Hospital, Stavanger, Norway; Department of Neurology, Stavanger University Hospital, Stavanger, Norway; Department of Clinical Medicine, Section of Neurology, University of Bergen, Bergen, Norway