Longitudinal cortical network reorganization in early relapsing–remitting multiple sclerosis

Vinzenz Fleischer, Nabin Koirala, Amgad Droby, René-Maxime Gracien, Ralf Deichmann, Ulf Ziemann, Sven G. Meuth, Muthuraman Muthuraman, Frauke Zipp, Sergiu Groppa
2019 Therapeutic Advances in Neurological Disorders  
Network science provides powerful access to essential organizational principles of the brain. The aim of this study was to investigate longitudinal evolution of gray matter networks in early relapsing-remitting MS (RRMS) compared with healthy controls (HCs) and contrast network dynamics with conventional atrophy measurements. For our longitudinal study, we investigated structural cortical networks over 1 year derived from 3T MRI in 203 individuals (92 early RRMS patients with mean disease
more » ... on of 12.1 ± 14.5 months and 101 HCs). Brain networks were computed based on cortical thickness inter-regional correlations and fed into graph theoretical analysis. Network connectivity measures (modularity, clustering coefficient, local efficiency, and transitivity) were compared between patients and HCs, and between patients with and without disease activity. Moreover, we calculated longitudinal brain volume changes and cortical atrophy patterns. Our analyses revealed strengthening of local network properties shown by increased modularity, clustering coefficient, local efficiency, and transitivity over time. These network dynamics were not detectable in the cortex of HCs over the same period and occurred independently of patients' disease activity. Most notably, the described network reorganization was evident beyond detectable atrophy as characterized by conventional morphometric methods. In conclusion, our findings provide evidence for gray matter network reorganization subsequent to clinical disease manifestation in patients with early RRMS. An adaptive cortical response with increased local network characteristics favoring network segregation could play a primordial role for maintaining brain function in response to neuroinflammation.
doi:10.1177/1756286419838673 pmid:31040880 pmcid:PMC6482642 fatcat:2mbwrcnhl5dsfdvhrvjoudl44u