1. Nuffield Department of Clinical Neurosciences, University of Oxford , Level 6 West Wing, John Radcliffe Hospital, Oxford , UK
2. Joyce D. and Andrew J. Mandell Center for Comprehensive Multiple Sclerosis Care and Neuroscience Research, Mount Sinai Rehabilitation Hospital, Trinity Health of New England , Hartford, CT , USA
3. Department of Neurology, Vita-Salute San Raffaele University , Milan , Italy
4. Casa di Cura del Policlinico , Milan , Italy
5. Experimental Neurophysiology Unit, Institute of Experimental Neurology-INSPE, IRCCS Scientific Institute San Raffaele , Milan , Italy