Continuous diffuse brain atrophy independent of relapse as a hallmark of multiple sclerosis beginning from relapsing-remitting stage.

ABSTRACT

BACKGROUND: Neurodegenerative changes are observed in relapsing-remitting multiple sclerosis (RRMS) and are prominent in secondary progressive MS (SPMS). However, whether neurodegenerative changes accelerate and are altered after the transition into SPMS or in the presence of relapses remains uncertain. METHODS: In this study, 73 patients with MS (seven with relapsing RRMS, 56 with relapse-free RRMS, and 10 with relapse-free SPMS) were evaluated for brain segmental volume changes over a 2-year follow-up period. Volume change was calculated using a within-subject unbiased longitudinal image analysis model. RESULTS: The rates of brain volume change in the 11 brain regions evaluated were relatively similar among different brain regions. Moreover, they were similar among the relapsing RRMS, relapse-free RRMS, and SPMS groups, even after adjusting for age. CONCLUSIONS: The relatively constant brain segmental atrophy rate throughout the disease course, regardless of relapse episodes, suggests that RRMS and SPMS are continuous, uniform, and silent progressing brain atrophy diseases on a spectrum.