Cross-Modal Plasticity Among Sensory Networks in Neuromyelitis Optica Spectrum Disorders (S12.007)

Objective: To compare resting state (RS) functional connectivity (FC) within and among RS networks (RSN) between patients with neuromyelitis optica spectrum disorder (NMOSD, 2015 criteria), isolated recurrent optic neuritis (ON) and recurrent myelitis. Background: The assessment of large-scale network RS FC abnormalities may help to define the selectivity of system involvement (e.g., visual and motor network) in NMOSD patients. Methods: RS fMRI was acquired from 30 right-handed NMOSD, 11 ON, 12 myelitis patients and 30 healthy controls (HC). Independent component analysis identified the main sensory and motor networks. Between-group comparison and correlations with motor performance (9-hole peg test and 10m-walking test) were assessed using SPM12. Inter-network connectivity modifications were estimated with a functional network connectivity (FNC) analysis. Results: Compared with HC, NMOSD patients showed decreased RS FC of the secondary visual network. They also showed increased RS FC of the visual and auditory networks vs HC, ON and myelitis. No sensorimotor RS FC abnormalities were detected. ON patients experienced decreased RS FC of the visual and auditory networks and increased RS FC of primary visual regions. Myelitis patients had reduced RS FC of the sensorimotor, visual and auditory networks vs HC, NMOSD and ON. They also showed increased RS FC of the precuneus (sensorimotor network) and cerebellum (visual network). In all groups, decreased RS FC correlated with poor motor performance. In myelitis increased precuneus RS FC correlated with a better motor performance. FNC between motor and visual RSNs was increased in NMOSD, while FNC was markedly decreased between primary and secondary visual RSNs in ON. Conclusions: In recurrent ON and myelitis, abnormal RS FC was observed in networks primarily affected by the pathological process. NMOSD showed decreased visual system RS FC and increased RS FC in other sensory networks, suggesting cross-modal plasticity among different sensory modalities.