Depletion of brain functional connectivity enhancement leads to disability progression in multiple sclerosis: A longitudinal resting-state fMRI study.

Mult Scler. 2016 Feb 2;

Authors: Faivre A, Robinet E, Guye M, Rousseau C, Maarouf A, Le Troter A, Zaaraoui W, Rico A, Crespy L, Soulier E, Confort-Gouny S, Pelletier J, Achard S, Ranjeva JP, Audoin B

Abstract
BACKGROUND: The compensatory effect of brain functional connectivity enhancement in relapsing-remitting multiple sclerosis (RRMS) remains controversial.
OBJECTIVE: To characterize the relationships between brain functional connectivity changes and disability progression in RRMS.
METHODS: Long-range connectivity, short-range connectivity, and density of connections were assessed using graph theoretical analysis of resting-state functional magnetic resonance imaging (fMRI) data acquired in 38 RRMS patients (disease duration: 120 ± 32 months) and 24 controls. All subjects were explored at baseline and all patients and six controls 2 years later.
RESULTS: At baseline, levels of long-range and short-range brain functional connectivity were higher in patients compared to controls. During the follow-up, decrease in connections' density was inversely correlated with disability progression. Post-hoc analysis evidenced differential evolution of brain functional connectivity metrics in patients according to their level of disability at baseline: while patients with lowest disability at baseline experienced an increase in all connectivity metrics during the follow-up, patients with higher disability at baseline showed a decrease in the connectivity metrics. In these patients, decrease in the connectivity metrics was associated with disability progression.
CONCLUSION: The study provides two main findings: (1) brain functional connectivity enhancement decreases during the disease course after reaching a maximal level, and (2) decrease in brain functional connectivity enhancement participates in disability progression.

PMID: 26838014 [PubMed - as supplied by publisher]