Background: Multiple Sclerosis (MS) is a neuroinflammatory disorder damaging structural connectivity. Natural remodeling processes of the nervous system can, to some extent, restore the damage caused. However, there is a lack of biomarkers to evaluate remodeling in MS. Objective: Evaluate graph theory metrics (esp. modularity) as a biomarker of remodeling and cognition in MS. Methods: We recruited 60 relapsing-remitting MS and 26 healthy controls. Structural and diffusion MRI, plus cognitive and disability evaluations, were done. We calculated modularity and global efficiency from the tractography-derived connectivity matrices. Association of graph metrics with T2 lesion load, cognition, and disability was evaluated using general linear models adjusting for age, gender, and disease duration wherever applicable. Results: We showed that MS subjects had higher modularity and lower global efficiency compared to controls. In the MS group, modularity was inversely associated with cognitive performance but positively with T2 lesion load. Conclusion: Our results indicate modularity increase is due to the disruption of inter-modular connections in MS due to lesions, with no improvement or preserving cognitive functions.
Handling Editor: Alex Fornito