[1] Helsinki Univ Hosp, Dept Neurol, Haartmaninkatu 4, FI-00029 Helsinki, Finland
[2] Univ Helsinki, Helsinki, Finland
[3] Univ Helsinki, Dept Publ Hlth, Helsinki, Finland
[4] La Paz Univ Hosp, Dept Neurol, Madrid, Spain
[5] Univ Gothenburg, Inst Neurosci & Physiol, Dept Clin Neurosci, Sahlgrenska Acad, Gothenburg, Sweden
[6] Sahlgrens Univ Hosp, Dept Neurol, Gothenburg, Sweden