1. From the Departments of Community Medicine (M.H., K.A.A.) and Clinical Medicine (S.H.J., E.B.M.), University of Tromsø, Tromsø, Norway; the Department of Radiology (M.H.), University Hospital of North Norway, Tromsø, Norway; and the Department of Neurology and Neurophysiology (S.H.J., K.A.A., E.B.M.), University Hospital of North Norway, Tromsø, Norway.