BACKGROUND: Little is known about cognitive outcomes in people with myelin oligodendrocyte glycoprotein-IgG associated disease (pwMOGAD). While there are similarities between MOGAD and multiple sclerosis (MS), further evaluation is needed to establish the distinct cognitive trajectories for each disease. METHODS: Retrospective review of subjective cognitive changes was performed for adult pwMOGAD. Subsets of pwMOGAD completed a cognitive screening measure and/or comprehensive neuropsychological testing. Their performance was compared to age, sex, and race matched people with MS (pwMS
3:1 ratio). RESULTS: Approximately half (51.6%) of pwMOGAD (n = 63) endorsed cognitive dysfunction. On a cognitive screening measure (Processing Speed Test [PST]), performance did not statistically differ between pwMOGAD (n = 36
M = -0.06, SD = 1.36) and pwMS (n = 108
M = -0.04, SD = 1.30), t(62.35) = 0.18, p = 0.86. Of the pwMOGAD who completed neuropsychological testing (total n = 14), 57% demonstrated cognitive impairment on at least one test, and 36% demonstrated impairment on two or more tests. These rates did not differ from pwMS. In pwMOGAD, deficits were most common in processing speed (38.5%) and verbal fluency, spatial judgment, and immediate list recall (14.3% each). PwMOGAD performed better than pwMS on measures of visuomotor processing speed (β = -0.378, t = -2.68, p = 0.01) and cognitive flexibility (β = -0.33, t = -2.27, p = 0.03) after controlling for age, sex, race, education, and disease duration. CONCLUSIONS: Subjective cognitive complaints and objective cognitive deficits were common among pwMOGAD. Approximately one-third of pwMOGAD demonstrated clinically significant cognitive impairment (2+ tests impaired) and individual level deficits were most common on measures of processing speed, verbal fluency, spatial judgment, and word list recall.