Cognitive impairment in primary and secondary progressive multiple sclerosis.

The aim of this study was to use neuropsychological data to characterize two subtypes of multiple sclerosis (MS) patients in a large patient sample. We studied patients with primary-progressive MS (PPMS) and secondary-progressive MS (SPMS). A group of 121 MS patients (36 PPS, 85 SPMS) and 40 healthy controls were administered a brief battery of cognitive tests. Executive functioning, memory and attention were studied. Results demonstrate that PPMS patients exhibited slightly more impairment than patients with SPMS, although this difference is not significant (50% vs 37%). However, PPMS patients revealed a significantly poorer performance in verbal learning (p < 0.05) and in verbal fluency (p < 0.05). Whereas PPMS patients had significantly shorter disease durations (p < 0.05), there was no statistical difference in disability between both groups. We conclude from our study that cognitive deficits in progressive MS are frequent. Patients with PPMS tend to be more frequently and severely affected than SPMS patients. Our findings of high prevalence of cognitive involvement in PPMS have not been reported previously