Neuropsychological effects of interferon beta-1a in relapsing multiple sclerosis

Cognitive dysfunction is common in multiple sclerosis (MS), yet few studies have examined effects of treatment on neuropsychological (NP) performance. To evaluate the effects of interferon beta -1a (IFN beta -1a 30 mug admini stered intramuscularly once weekly [Avonex]) on cognitive function, a Compr ehensive NP Battery was administered at baseline and week 104 to relapsing MS patients in the phase III study, 166 of whom completed both assessments. A Brief NP Battery was also administered at 6-month intervals. The primary NP outcome measure was 2-year change on the Comprehensive NP Battery, grou ped into domains of information processing and learning/memory (set A), vis uospatial abilities and problem solving (set B), and verbal abilities and a ttention span (set C). NP effects were most pronounced in cognitive domains vulnerable to MS: IFN beta -1a had a significant beneficial effect on the set A composite, with a favorable trend evident on set B. Secondary outcome analyses revealed significant between-group differences in slopes for Brie f NP Battery performance and time to sustained deterioration in a Paced Aud itory Serial Addition Test processing rate, favoring the IFN beta -1a group . These results support and extend previous observations of significant ben eficial effects of IFN beta -1a for relapsing MS.