1. Department of Rehabilitation Medicine; Institute of Neuroscience; University of Uppsala; Uppsala Sweden
2. Centre for Research and Development; Uppsala University/County Council of Gavleborg; Gavleborg Sweden
3. Medical Statistics Unit; Department LIME; Karolinska Institutet; Stockholm Sweden
4. Clinical Epidemiology Unit; Department of Medicine; Karolinska Institutet; Stockholm Sweden
5. Department of Clinical Sciences, Rehabilitation Medicine; Karolinska Institutet; Danderyd Hospital; Stockholm Sweden