In MS, can better sleep improve cognition?

http://www.eurekalert.org/pub_releases/2016-06/uomh-imc061316.php

Public Release: 13-Jun-2016
In MS, can better sleep improve cognition?
University of Michigan Health System

Multiple sclerosis looks different from person to person. In many individuals, though, the difficulty in maintaining a sense of self and in keeping up intellectually can be the disease's most devastating manifestations.

With this in mind, University of Michigan researchers are exploring a new way to improve cognitive issues, such as memory, attention and mental processing in MS patients: by examining sleep.

People with MS face an elevated risk of obstructive sleep apnea (OSA), a disorder in which the throat collapses during sleep, causing the patient to repeatedly stop breathing for periods of 10 seconds or longer throughout the night. OSA can lead to a decline in mental functioning.

A U-M pilot study published in Sleep is the first to find an association between sleep apnea severity and cognitive dysfunction in patients with MS.

"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?'" says Tiffany Braley, M.D., M.S., the principal investigator and co-first author of the study, and an assistant professor of neurology at U-M.

MS affects nearly half a million Americans and is the leading non-traumatic cause of neurological disability among young adults.

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"Multiple measures of sleep apnea severity directly correlated with poorer performance on several cognitive tests," said co-first author Anna Kratz, Ph.D., a clinical psychologist and assistant professor of physical medicine and rehabilitation. "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."

Apnea severity measures accounted for between 11 and 23 percent of the variance in cognitive test performance. The investigators also observed relationships between other sleep quality measures and poor cognitive performance.

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"Given the high prevalence of treatable sleep problems in MS patients, and the fact that many patients with MS rate fatigue as one of their most bothersome symptoms, physicians should have a low threshold to refer MS patients who report sleep disturbances to sleep specialists," says last author Ronald Chervin, M.D., M.S., professor of neurology and director of U-M Sleep Disorders Center.