To assess the cognitive sequelae of patients with myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD).

MOGAD is a recently recognized CNS demyelinating disease that frequently leads to encephalitis. There is very little information on the cognitive sequelae in MOGAD.

We identified 9 patients with MOGAD who underwent neuropsychological testing. Clinical information and neuropsychological assessments were analyzed via retrospective chart review.

The median age of this cohort was 33 years (17-65 years), among which 33% were female. MOG antibody titers ranged from 1:40 to 1:1000. Prior attacks of encephalitis had occurred in 8 of 9 (89%) patients. Seven (78%) had memory complaints and 2 (22%) had seizures. Of the 8 with prior cerebral attacks, the median time from the last cerebral attack to neuropsychological assessment was 147 days (range, 70-244 days). At the time of cognitive assessment, the median Expanded Disability Status Scale (EDSS) was 3 (range, 1-5.5) and the median Modified Rankins Scale (mRS) was 2 (range, 1-3). On neuropsychological assessment, impairment was classified as scores falling below the 5^th percentile of normative standards.  Deficits were observed in multiple domains, including verbal list learning, 1/8 (13%); list delayed recall 2/8 (25%); story learning, 1/8 (13%); short learning delayed recall, 2/8 (25%); visual learning, 2/7 (29%); visual delayed recall, 1/7 (14%); confrontation naming, 2/8 (25%); lexical fluency, 4/9 (44%); semantic fluency, 3/9 (33%); visuospatial perception, 2/7 (29%); auditory working memory 1/7 (15%); visual attention/ processing speed, 1/6(17%); set-shifting, 2/9 (22%) and concept formation, 2/7(29%). Collectively, 4/9 (44%) of the sample achieved impaired performance in one or more domains.

Up to 44% of this clinically referred MOGAD sample displayed salient cognitive impairment, most often in new-learning and executive function.  Such impairment could impact activities of daily living, ability to retain employment and impair learning in school aged children.