The Kurtzke EDSS rank stability increases 4 years after the onset of multiple sclerosis: results from the MSBase Registry

- Hughes, Stella; Spelman, Timothy; Hupperts, Raymond; Boz, Cavit; Bergamaschi, Roberto; Giuliani, Giorgio; Rio, Maria Edite; Lechner-Scott, Jeannette; Van Pesch, Vincent; Iuliano, Gerardo; Fiol, Marcela; Verheul, Freek; Trojano, Maria; Lugaresi, Alessandra; Izquierdo, Guillermo; Grand'Maison, Francois; Duquette, Pierre; Girard, Marc; Grammond, Pierre; Oreja-Guevara, Celia