1. Department of Neurology, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
2. Department of Public Health, University of Helsinki, Helsinki, Finland
3. Department of Neurology, La Paz University Hospital, Madrid, Spain
4. Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
5. Department of Neurology, Sahlgrenska University Hospital, Gothenburg, Sweden