Abstract Details

Voxel-wise DC on resting-state functional MRI (RS fMRI) scans may assess how functional brain networks undergo topography changes in MS.

To assess degree centrality (DC) abnormalities in multiple sclerosis (MS) patients and to evaluate their association with disease course.

971 MS patients (47 clinically isolated syndrome [CIS]; 704 relapsing-remitting MS [RRMS]; 145 secondary progressive MS [SPMS] and 75 primary progressive MS [PPMS]) and 330 healthy controls (HCs) underwent RS fMRI and clinical assessment. SPM12 age-, sex-, centre- and gray matter volume adjusted ANOVA and multivariable regressions were employed. All p were <0.05 family wise error corrected unless otherwise specified.

MS patients showed reduced DC in the bilateral insula, caudate nucleus, paracentral lobule, postcentral gyrus, right (R) precentral gyrus and left (L) temporo-parietal cortex and increased DC in the R precuneus, R middle temporal gyrus (MTG) and bilateral middle occipital gyrus (MOG) vs HCs. These DC abnormalities were mostly observed in RRMS and SPMS. SPMS showed reduced DC in the R thalamus and increased DC in fronto-temporal areas vs both HCs and RRMS. Conversely, CIS patients presented with increased DC in the R precuneus and PPMS showed increased DC in frontal areas vs HCs (p<0.001, uncorrected). In MS, more severe disability correlated with reduced DC in the L sensory-motor areas. Cognitively impaired patients showed reduced DC in the R postcentral gyrus and increased DC in the R precuneus and MTG and bilateral MOG vs HCs and cognitively preserved MS patients.

MS patients undergo a progressive DC reduction of the sensorimotor network throughout the disease course, and a concomitant DC increase of the default mode network. These findings suggest that MS pathology may produce a sensorimotor network collapse, with a possible attempt of the default mode network to counteract for such a collapse.