BRAIN AND LESION VOLUMES CORRELATE WITH EDSS IN RELAPSING-REMITTING MULTIPLE SCLEROSIS.

Abstract

Background: Demyelination and neurodegeneration are hallmarks of multiple sclerosis (MS). Axonal damage is considered to be the leading factor for persisting disability in the course of the disease. In different studies, expanded disability status scale (EDSS) scores have been found to correlate with brain atrophy, lesion load, or both. Objective: To assess the possible correlations between EDSS scores and volumes of brain, grey and white matter, and subcortical structures in patients with relapsing-remitting multiple sclerosis. Subjects and Methods: 46 patients with RRMS were included in the study. Total brain volume, grey and white matter volumes were calculated using SIENAX, and subcortical structure volumes were obtained using FIRST, parts of FSL. EDSS was scored by a qualified rater. Statistical analysis was performed. Results: Moderate negative correlation of EDSS was demonstrated with total brain volume, grey and white matter volume, volumes of left and right pallidum, putamen, caudate nucleus, n. accumbens (p<0.01), and with the volumes of left and right thalamus (p<0.05). Moderate positive correlation was found between EDSS and T2 lesion volume (p<0.01). Correlation between EDSS and hippocampal volumes was weak. Conclusions: Our results demonstrate that in patients with relapsing-remitting multiple sclerosis, higher disability correlates with lower volumes of brain, grey and white matter, and some subcortical structures, but also with higher T2 lesion load. We support the hypothesis about a possible causal relationship between white matter damage and brain atrophy, as well as the role of both demyelination and neurodegeneration for disability in MS