People who have sleep apnea and spend less time in deep sleep may be more likely to have brain biomarkers that have been linked to an increased risk of stroke, Alzheimer’s disease and cognitive decline, according to new research published in the May 10, 2023, online issue of Neurology®, the medical journal of the American Academy of Neurology. The study does not prove that these sleep disturbances cause the changes in the brain, or vice versa. It only shows an association.
The study looked at sleep factors and biomarkers of the health of the brain’s white matter. The biomarkers measure how well the brain’s white matter is preserved, which is important to connect different parts of the brain. One of the biomarkers, white matter hyperintensities, are tiny lesions visible on brain scans. White matter hyperintensities become more common with age or with uncontrolled high blood pressure. The other biomarker measures the integrity of the axons, which form the nerve fibers that connect nerve cells.
“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.”