From the Department of Neurology (M.I.B., A.H.M., C.M.E.T.) and Oslo Centre for Biostatistics and Epidemiology (C.B., H.W.-F.), Research Support Services, Oslo University Hospital, Norway; Department of Neurology (J.J.G.M.V.), Leiden University Medical Centre, the Netherlands; and Institute of Clinical Medicine (M.I.B., C.M.E.T.), University of Oslo, Norway. (At 2016-11-15)