Title: Brain structural and functional alterations in MOG antibody disease Authors

Background The impact of myelin oligodendrocyte glycoprotein antibody disease (MOGAD) on brain structure and function are unknown. Objectives To study multimodal brain MRI alterations in MOGAD and investigate their clinical significance. Methods Seventeen MOGAD, 20 aquaporin-4 antibody seropositive neuromyelitis optica spectrum disorders (AQP4+ NMOSD) and 28 healthy controls (HC) were prospectively recruited. Voxelwise gray matter (GM) volume, fractional anisotropy (FA), mean diffusivity (MD) and degree centrality (DC) were compared between groups. Clinical associations and differential diagnosis were determined using partial correlation and stepwise logistic regression. Results In comparison to HC, MOGAD had GM atrophy in frontal and temporal lobe, insula, thalamus, and hippocampus, and WM fiber disruption in optic radiation and anterior/posterior corona radiata; DC decreased in cerebellum and increased in temporal lobe. Compared to AQP4+ NMOSD, MOGAD presented lower GM volume in postcentral gyrus and decreased DC in cerebellum. Hippocampus/parahippocampus atrophy associated with Expanded Disability Status Scale (R=-0.55, p=0.04) and California Verbal Learning Test (R=0.62, p=0.031). The differentiation of MOGAD from AQP4+ NMOSD achieved an accuracy of 95% using FA in splenium of corpus callosum and DC in occipital gyrus.