1. From the Department of Clinical Neuroscience (V.S., A.F.-S., V.G.E.-H., M.A., O.S., E.E.), Karolinska Institutet; Department of Neurology (V.S., C.H., M.A.), and Department of Neurosurgery (A.F.-S., V.G.E.-H., E.E.), Karolinska University Hospital; Department of Neurobiology, Care Sciences and Society (C.H.), Karolinska Institutet, Stockholm, Sweden; Department of Neurology (O.S.), Landspitali, Reykjavik, Iceland; Stockholm Spine Center (A.E.-T.), Löwenströmska Hospital, Upplands Väsby; and...