Prevalence and Risk of Cognitive Impairment in Multiple Sclerosis Subtypes and Neuromyelitis Optica Spectrum Disorder: A Case-Control Study (ORP-08)

Background: Autoimmune demyelinating disorders like Multiple Sclerosis (MS) and Neuromyelitis Optica Spectrum Disorder (NMOSD) result from ongoing inflammation and damage to the central nervous system. Cognitive impairment (CI) is increasingly recognized as a significant challenge in these disorders, highlighting the need to investigate its prevalence and associated risks across various MS subtypes and NMOSD.
Objective: This study aimed to evaluate the prevalence and odds of CI, assessed using the Symbol Digit Modalities Test (SDMT), in different MS subtypes and NMOSD.
Methods: A case-control study was conducted with 616 participants, including healthy controls (HC) and individuals with different MS subtypes (relapsing-remitting MS (RRMS), secondary progressive MS (SPMS), primary progressive MS (PPMS)), clinically isolated syndrome (CIS), and NMOSD. CI was defined as SDMT scores 1.5 standard deviations below the HC average.
Results: CI prevalence varied among the groups: HC (10.7%), RRMS (33.8%), SPMS (71.3%), PPMS (62.8%), CIS (19.2%), and NMOSD (32.8%). The odds ratios (OR) for CI were significantly higher in RRMS (OR: 4.23), SPMS (OR: 20.58), PPMS (OR: 14.02), and NMOSD (OR: 4.04) compared to HC, while the increase was not statistically significant in CIS (OR: 1.97). Additionally, no significant difference in CI risk was observed between RRMS and NMOSD.
Conclusion: The study highlights a significantly elevated risk of CI in various MS subtypes and NMOSD compared to healthy controls. While no significant difference in CI risk was found between RRMS and NMOSD, individuals with progressive forms of MS showed markedly higher risks of CI.