# Effect of methylphenidate on oculomotor function in individuals with multiple sclerosis: a pilot randomized placebo-controlled trial

## TL;DR

This study found that methylphenidate improves oculomotor speed in people with multiple sclerosis, which may help with visual-based cognitive tasks.

## Contribution

The study is the first to show methylphenidate's effect on oculomotor function and its link to improved visuomotor information processing speed in MS.

## Key findings

- Methylphenidate significantly improved oculomotor speed compared to placebo in individuals with MS.
- Improved oculomotor speed was correlated with better performance on the Symbol Digit Modalities Test, a visuomotor IPS assessment.
- No correlation was found between oculomotor improvement and performance on the auditory-verbal Paced Auditory Serial Addition Test.

## Abstract

Individuals with multiple sclerosis (MS) frequently experience visual and oculomotor symptoms that may impact and confound neuropsychological assessments of information processing speed (IPS). In this study, we examined the effect of the psychostimulant methylphenidate on oculomotor function and the association between change in oculomotor speed and change in information processing speed.

We used a repeated measures crossover design in which a sample of 11 participants with MS were randomly assigned to one of two treatment arms: one that received methylphenidate for 4 weeks and another that received a placebo for 4 weeks. After a 7-day washout period, the treatments were crossed over. The King Devick test, the Symbol Digit Modalities Test, and the Paced Auditory Serial Addition Test were administered at baseline and after each of the two study arms.

We found a significant improvement in oculomotor speed in the methylphenidate condition as compared to placebo. This improvement was significantly correlated with improvement on a visuomotor assessment of IPS (Symbol Digit Modalities Test), but no such association was found for an auditory-verbal assessment of IPS (Paced Auditory Serial Addition Test).

These findings suggest that individuals with MS experience improved oculomotor speed while taking methylphenidate, which may, in turn, improve performance on assessments of IPS with visuomotor demands.