Association of peripapillary retinal nerve fiber layer atrophy with cognitive impairment in patients with neuromyelitis optica spectrum disorder

We aimed to explore the association between peripapillary retinal nerve fiber layer thickness (pRNFL), macular ganglion cell-inner plexiform layer (mGCIPL), and cognitive impairment (CI) in patients with neuromyelitis optica spectrum disorder (NMOSD).

In this cross-sectional study, 38 (28 aquaporin-4 (AQP4) IgG-seropositive) NMOSD patients and 20 healthy controls (HC) underwent cognitive assessment using Minimal Assessment of Cognitive Function in Multiple Sclerosis (MACFIMS) battery. Spectral-domain optical coherence tomography (OCT) was performed for both eyes of all NMOSD patients. First, we examined the association of pRNFL and mGCIPL with cognitive function in all patients, regardless of the history of previous optic neuritis (ON). We then included only eyes without a prior history of ON, incorporating non-ON eyes in patients with unilateral ON and the average of OCT measures for both non-ON eyes in patients without a history of ON.

Sixteen (42.1%) NMOSD patients exhibited global CI. There was a significant decrease in pRNFL (Δ: 24.33 μm, p = 0.002) and mGCIPL (Δ: 9.20 μm, p = 0.009) in NMOSD patients with CI compared to those without. The atrophy of pRNFL showed an inverse association with CI before (OR = 1.059, 95% CI: 1.015, 1.105) and after adjustment for age, sex, and disease duration (OR = 1.072, 95%CI: 1.009, 1.139). An inverse significant association was observed between mGCIPL atrophy and CI before adjustment (OR = 1.102, 95% CI: 1.017, 1.194), but not after adjustment (OR = 1.106, 95%CI: 0.999, 1.224). After narrowing our analysis to non-ON eyes, the same results for pRNFL and CI were observed (unadjusted: OR = 1.054, 95% CI: 1.004, 1.106; adjusted: OR = 1.081, 95%CI: 1.000, 1.168). There was no significant association found between mGCIPL thickness and CI in both unadjusted and adjusted models. In sensitivity analyses, we observed no significant association between pRNFL and mGCIPL with CI in AQP-IgG-seropositive NMOSD patients.

This study, for the first time, provide a preliminary evidence for a possible relation between pRNFL atrophy and occurrence of cognitive impairment in NMOSD patients. Further studies are required to explore the possible association of OCT parameters with cognition function in NMOSD patients.