Defining secondary progressive multiple sclerosis

- Lorscheider, Johannes; Buzzard, Katherine; Prat, Alexandre; Lugaresi, Alessandra; Grand'Maison, François; Grammond, Pierre; Hupperts, Raymond; Alroughani, Raed; Sola, Patrizia; Boz, Cavit; Pucci, Eugenio; Lechner-Scott, Jeanette; Jokubaitis, Vilija; Bergamaschi, Roberto; Oreja-Guevara, Celia; Iuliano, Gerardo; Van Pesch, Vincent; Granella, Franco; Ramo-Tello, Cristina; Spitaleri, Daniele; Petersen, Thor; Slee, Mark; Verheul, Freek; Spelman, Tim; Ampapa, Radek; Amato, Maria Pia; McCombe, Pamela; Vucic, Steve; Sánchez Menoyo, José Luis; Cristiano, Edgardo; Barnett, Michael H.; Hodgkinson, Suzanne; Olascoaga, Javier; Laura Saladino, Maria; Havrdova, Eva; Gray, Orla; Shaw, Cameron; Moore, Fraser; Butzkueven, Helmut; Kalincik, Tomas; Horakova, Dana; Trojano, Maria; Izquierdo, Guillermo; Girard, Marc; Duquette, Pierre