One year follow up study of primary and transitional progressive multiple sclerosis

Objective—To document clinical and mag- netic resonance imaging (MRI) character- istics of a large cohort of primary and transitional progressive multiple sclerosis (PP and TP MS) patients over one year. Introduction—Patients with PP or TP MS have been shown to have low brain T2 and T1 lesion loads and slow rates of new lesion formation with minimal gadolin- ium enhancement, despite their accumu- lating disability. Serial evaluation of these patients is needed to elucidate the patho- logical processes responsible for disease progression and to identify clinical and MRI measures which can monitor these processes in treatment trials. Method—Patients, recruited from six Eu- ropean centres, underwent two assess- ments on the expanded disability status scale (EDSS) and MRI of the brain and spinal cord, 1 year apart. Results—Of the 167 patients studied (137 with PP MS and 30 with TP MS), 41 (25%; 35 PP and six TP) showed a one step increase in the EDSS. The mean number of new brain lesions seen was 0.88 in the PP group and 0.47 in the TP MS group. Both groups demonstrated change in T2 lesion load over the year (p