| Clinical attacks | Objective lesion | Additional requirement |
| 2 or more | 2 or more | None |
| 2 or more | 1 | Dissemination in space by MRI or 2 or more MRI lesions consistent with MS plus positive CSF |
| 1 | 2 or more | Dissemination in time by MRI or second clinical attack |
| 1 | 1 | Dissemination in space by MRI or 2 or more MRI lesions consistent with MS plus positive CSF and dissemination in time by MRI or second clinical attack |
| 0 | 1 or more | Disease progression for 1 year and 2 out of 3 of the following a) Positive brain MRI b) Positive spinal cord MRI c) Positive CSF |