[1] IRCSS Fdn Don Carlo Gnocchi, Milan, Italy
[2] CRRF Mons Luigi Novarese, Moncrivello, VC, Italy
[3] Italian MS Fdn FISM, Sci Res Area, Genoa, Italy
[4] IRCCS Fdn Carlo Besta Neurol Inst, Milan, Italy
[5] S Camillo Forlanini Hosp, Dept Neurosci, C Ne Gianicolense 87, I-00152 Rome, Italy