The prevalence of cognitive impairment in patients with neuromyelitis optica spectrum disorders (NMOSD): A systematic review and meta-analysis.

OBJECTIVE To estimate pooled prevalence of cognitive impairment in neuromyelitis opticaspectrum disorders (NMOSD) cases. METHODS We searched PubMed, Scopus, EMBASE, Web of Science, and google scholar. We also searched the gray literature including references of the included studies, and conference abstracts which were published up to 20th October 2020. The search strategy included the MeSH and text words as (((Cognitive Dysfunctions) OR Cognitive Impairment) OR Cognitive Declines) OR Mild Cognitive Impairment) OR Mental Deterioration) AND (Neuromyelitis Optica spectrum disorder OR NMOSD OR Devic syndrome OR Neuromyelitis Optica spectrum disorders). RESULTS The literature search revealed 1830 articles, after deleting duplicates 1434 remained. For the meta-analysis, 25 studies were included. Totally, 761 NMOSD patients were evaluated and 329 patients had cognitive impairment. Mean age ranged from 34-53 years. The prevalence of cognitive impairment ranged from 3% to 75%.The pooled prevalence of cognitive impairment was 44%, 95%CI(35%-54%), (I2=89.1%, P<0.001) which shows a high statistical heterogeneity . By excluding the abstract of Jung et al which was published in 2009, we found that the pooled prevalence was 34% (95% CI:31-37%) (I2=0) CONCLUSION: Cognitive impairment should be considered in NMOSD patients as its pooled prevalence is estimated as 44%.