Sleep Apnea Associated with Cognitive Dysfunction in Multiple Sclerosis Patients

A study published in Sleep found an association between the severity of obstructive sleep apnea (OSA) and cognitive dysfunction in multiple sclerosis (MS) patients.

“Since obstructive sleep apnea is a treatable condition that is also commonly seen in MS, we wondered, ‘What if some of the thinking and processing difficulties that MS patients experience do not stem directly from the MS itself, but from the effects of sleep apnea or other sleep problems?’” said co-first study author Tiffany Braley, MD, MS.

A pilot study enrolled 38 adult MS patients given 7 cognitive tests, which included word list recall, reproducing figures and pictures, and calculation.

Additionally, participants were given a polysomnography at the Michael S. Aldrich Sleep Disorders Laboratory. There were 33 patients who met the OSA criteria.

The apnea severity measures accounted for between 11% and 23% of the variance in cognitive test performance. Furthermore, researchers saw a relationship between a poor cognitive performance and other sleep quality measures.

“Multiple measures of sleep apnea severity directly correlated with poorer performance on several cognitive tests,” said co-first author Anna Kratz, PhD. “In particular, problems with attention and multiple aspects of memory, including memory for words and images, and working memory, which plays a role in problem solving and decision making, were all associated with poorer sleep.”

Next, researchers hope to replicate the findings in a larger sample size of MS patients, and treat the participants with OSA with positive airway pressure therapy. The upcoming clinical trial will look to determine if MS patient cognitive function improves when their sleep apnea is treated.

Researchers noted that due to the high prevalence of sleep issues in MS patients, physicians should have a low threshold for referring patients to sleep specialist when they report sleeping problems.

“Current MS treatments can prevent further neurological damage, but do little to help existing MS symptoms and damage,” Braley said. “Our focus on sleep is part of a larger collaborative initiative to identify previously overlooked but nonetheless treatable conditions that could be affecting patients with MS. Identifying and successfully treating conditions like OSA could help us find new ways to improve the cognitive function in MS.”