1. Department of Neurology, Hospital General Universitario Gregorio Marañón, Madrid, Spain
2. Department of Neurology, Hospital Clínico Universitario Lozano Blesa, Faculty of Medicine, Zaragoza, Spain
3. Department of Pathology and Experimental Therapeutics, University of Barcelona, Campus Bellvitge, CIBERNED, Hospitalet de Llobregat, Barcelona, Spain
4. Department of Neurology, School of Medicine, and Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, Oregon, USA