Cognitive dysfunction is common among patients with multiple sclerosis (MS), but the effect of coexisting optic neuritis (ON) at the presentation of multiple sclerosis on the course of cognitive decline is unknown. The purpose of a recent cohort study—believed to be the first of its kind—was to determine whether ON at the first sign has any effect on the progression of cognitive decline in MS.

A total of 170 MS patients were a part of this study. The MS-ON group included 46 patients having ON involvement at the time of the first presentation, and the remaining 124 patients in the MS-non-ON group did not.

No significant differences were found in cognitive performance at onset between the two groups, and both had a similar follow-up duration. The prevalence of cognitive decline in the general score was significantly higher in the MS-ON group compared with the MS-non-ON group. A trend toward higher prevalence of cognitive decline was also observed in the MS-ON group for the information processing speed, motor skills and verbal function domains.

“Although no differences were found between these two groups in terms of cognitive function at presentation, our analysis showed a significantly higher rate of MS patients who experienced

a decrease in overall cognitive function in the MS-ON group over time,” the authors concluded in their study. “The most affected domains responsible for this decline were executive function and attention. The multivariate regression model showed that these differences were not affected by gender, age at presentation, disease duration or treatment. Severity of visual function loss at presentation also did not seem to reflect the change in cognitive test results.”

The authors note future prospective studies are warranted for better understanding of this association, and interventional studies should explore the potential benefit of early treatment for the prevention of cognitive decline.