1. Centre for Movement Disorders, Stavanger University Hospital, Stavanger, Norway
2. Department of Chemistry, Bioscience and Environmental Engineering, University of Stavanger, Stavanger, Norway
3. Department of Neurology, Haukeland University Hospital, Bergen, Norway
4. Department of Clinical Medicine, University of Bergen, Bergen, Norway
5. Department of Neurology, Stavanger University Hospital, Stavanger, Norway