Summary of Sleep Apnea, Lack of Deep Sleep May Be Wrecking Your Brain:
New research published in Neurology suggests that individuals with sleep apnea who spend less time in deep sleep may be more likely to have brain biomarkers associated with an increased risk of stroke, Alzheimer’s disease, and cognitive decline. The study, which involved 140 participants with obstructive sleep apnea, found that decreased slow-wave sleep was linked to increased white matter hyperintensities and reduced axonal integrity, indicative of early cerebrovascular disease. While the research does not establish causation, it highlights the need for further investigation into sleep quality improvement and sleeps apnea treatment to affect these biomarkers’ trajectory potentially.
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Sleep Apnea Linked to Increased Risk of Stroke and Alzheimer’s Disease
A recent study published in the medical journal Neurology has found a link between sleep apnea, reduced deep sleep, and brain biomarkers linked to stroke, Alzheimer’s disease, and cognitive decline. While the research doesn’t establish causation, it highlights the need for further investigation into sleep quality improvement and sleeps apnea treatment to affect these biomarkers’ trajectory potentially.
The Study
The study involved 140 people with obstructive sleep apnea, an average age of 73, with a brain scan and an overnight analysis in a sleep lab. 34% had mild, 32% had moderate, and 34% had severe sleep apnea. The participants did not have cognitive issues at the start of the study and had not developed dementia by the end.
The Results
The sleep study examined how long people spent in slow-wave sleep, also called non-REM stage 3 or deep sleep, and is considered one of the best markers of sleep quality. The researchers found that for every 10-point decrease in the percentage of slow-wave sleep, there was an increase in the number of white matter hyperintensities similar to the effect of being 2.3 years older. The same decrease was also associated with reduced axonal integrity, identical to the impact of being three years older.
People with severe sleep apnea had more white matter hyperintensities than mild or moderate sleep apnea. They also had reduced axonal integrity in the brain.
“These biomarkers are sensitive signs of early cerebrovascular disease,” said study author Diego Z. Carvalho, MD, MS, of the Mayo Clinic in Rochester, Minnesota, and a member of the American Academy of Neurology. “Finding that severe sleep apnea and a reduction in slow-wave sleep are associated with these biomarkers is important since there is no treatment for these changes in the brain, so we need to find ways to prevent them from happening or getting worse.”
Implications and Further Research
The study does not prove that sleep disturbances cause changes in the brain or vice versa. Further research is needed to determine whether sleep issues affect these brain biomarkers or vice versa. Strategies to improve sleep quality or treatment of sleep apnea could affect these biomarkers’ trajectory and reduce the risk of stroke and Alzheimer’s disease.
The split-night design of the sleep study led to a limitation of this comprehensive study. Participants sleep was observed, and their sleep factors were measured until they met the criteria for the diagnosis of obstructive sleep apnea, mainly in the first two to three hours of sleep. Then they received a positive airway pressure machine for the rest of the night. So the sleep measurements may not represent a whole night of sleep.
In conclusion, the study highlights the importance of adequate sleep and the need for effective sleep apnea treatment to minimize the risk of stroke and Alzheimer’s disease. Further research is needed to determine the nature of the relationship between sleep disturbances and these brain biomarkers and to pinpoint effective interventions.
