1. Neuroscience Research Group, Department of Neurology, Stavanger University Hospital, Stavanger, Norway
2. Department of Neurology, Haukeland University Hospital, Bergen, Norway; Department of Clinical Medicine, University of Bergen, Bergen, Norway
3. Section of Biostatistics, Department of Research, Stavanger University Hospital, Stavanger, Norway
4. Neuroscience Research Group, Department of Neurology, Stavanger University Hospital, Stavanger, Norway; Department of Clinical Medicine, University of Bergen, Bergen, Norway