Visual system damage and network maladaptation are associated with cognitive performance in neuromyelitis optica spectrum disorders.

Background Neuromyelitis Optica Spectrum Disorders (NMOSD) is an autoimmune disease leading to disability from optic neuritis, myelitis and more rarely brain stem attacks and encephalitis. Patients with NMOSD also exhibit cognitive deficits, the cause of which remains unclear. Recent evidence highlights sensory-cognitive parallel processing converging on the primary visual cortex. The objective of this study was to investigate the effect of the primary visual network disruption from damage caused by optic neuritis on cognition in NMOSD. Methods Twenty-nine aquaporin-4 antibody seropositive patients with NMOSD and 22 healthy controls (HC) completed the brief repeatable battery of neuropsychological tests (BRB-N) and underwent 3 Tesla MRI. Primary visual network functional connectivity (FC) at resting state was analyzed and correlated with performance on BRB-N. These correlations were compared between the groups. Results Patients performed significantly worse than HC on the BRB-N Index score (t = 2.366, p = 0.02). Among HC, visual network FC decreased significantly as cognitive performance on the BRB-N Index score increased (rho(17)=-0.507, p = 0.02). Among patients, this association was absent (rho(23)=0.197, p = 0.18), and the difference in correlation direction and strength to HC was significant (z=-2.175, p = 0.01). Visual network FC was able to explain 19% of the variance in cognitive performance in HC, but none in patients. Conclusions A physiological association of the primary visual network FC and cognitive performance appears absent in patients with NMOSD, suggesting a partial explanation for cognitive deficits. Our findings extend neuroscientific concepts on sensory-cognitive parallel processing neural networks to a clearly defined pathological state, and may be relevant for other diseases with visual system damage.