1. Department of General Practice, Institute of Health and Society, University of Oslo, Oslo, and Research Centre, Akershus University Hospital, Lørenskog, Norway
2. Research Centre, Akershus University Hospital, Lørenskog, Norway; Institute of Clinical Medicine, Campus Akershus University Hospital, University of Oslo, Nordbyhagen, Norway, and Department of Neurology, Akershus University Hospital, Nordbyhagen, Norway