[1] Univ Barcelona, Serv Neurol, Hosp Clin, Barcelona, Spain
[2] Inst Invest Biomed August Pi & Suyer IDIBAPS, Barcelona, Spain
[3] Hosp Cruces, Dept Neurol, Baracaldo, Spain
[4] Hosp Clin Barcelona, IDIBAPS, ICREA, Barcelona, Spain
[5] Med Univ Vienna, Inst Neurol, Vienna, Austria
[6] Univ Penn, Dept Neurol, Philadelphia, PA 19104 USA