Author information:
(1)Neuromuscular Disease, IRCCS Foundation, "Carlo Besta" Neurological 
Institute, Milan, Italy.
(2)NESMOS Department, Neuromuscular Disease Unit, Sant'Andrea Hospital and 
University of Rome "Sapienza", Rome, Italy.
(3)Neurologic Unit, Monserrato University Hospital, Cagliari, Italy.
(4)Neurologic Clinic, SS. Annunziata Hospital, Chieti, Italy.
(5)Departments of Neurosciences, Rehabilitation, Ophtalmology, Genetics, Mother 
and Child Disease, IRCCS University Hospital San Martino IST, Genova, Italy.
(6)Department of Neurosciences, ALS Centre, "Rita Levi Montalcini" Azienda 
Ospedaliero Universitaria Città della Salute e della Scienza, Turin, Italy.
(7)NEMO Clinical Centre, Milan, Italy Department of Neurorehabilitaton, Casa 
Cura Policlinico, Milan, Italy.
(8)Neurology Unit, S. Maria della Misericordia University Hospital, Udine, 
Italy.
(9)Department of Neurology, IRCCS "San Raffaele" Hospital, Milan, Italy.
(10)Neurologic Clinic, University of Brescia, Brescia, Italy.
(11)Department of Medical and Surgery Sciences and Neurosciences, University of 
Siena, Siena, Italy.
(12)Neurologic Clinic, University of Ferrara, Italy.
(13)ALS Research Centre, BioNeC, University of Palermo, Palermo, Italy.
(14)Department of Neurology and Psychiatry, University of Bari, Bari, Italy.
(15)Department of Neurosciences, S. Agostino-Estense Hospital, Modena, Italy.
(16)ALS Centre, Neurologic Clinic, Maggiore della Carità University Hospital, 
Novara, Italy.
(17)2nd Neurologic Clinic, 2nd University of Naples, Naples, Italy.
(18)IRCCS "Salvatore Maugeri" Foundation, Milan, Italy.
(19)Department of Neurosciences, Neurology Unit, University of Parma, Parma, 
Italy.
(20)Neurology Unit, dell'Angelo Hospital, Mestre, Italy.
(21)Neurology Unit, Department of Neuro-Motor Diseases, IRCCS Arcispedale Santa 
Maria Nuova, Reggio Emilia, Italy.
(22)IRCCS Neurological Sciences Institute, Bologna, Italy.
(23)Department of Clinical and Experimental Medicine, Neurology Unit, University 
of Pisa, Pisa, Italy.
(24)Department of Neurosciences, University of Padua, Padua, Italy.
(25)Intensive Neurorehabilitation Unit, IRCCS "Salvatore Maugeri" Foundation, 
Mistretta, Italy.
(26)Neuroepidemiology Units, IRCCS Foundation, "Carlo Besta" Neurological 
Institute, Milan, Italy.