A recent study published in the journal Neurology has found that individuals with sleep apnea who spend less time in deep sleep may be at a higher risk of developing brain biomarkers associated with stroke, Alzheimer’s disease, and cognitive decline. While the study did not establish a causal relationship, it revealed a significant association between sleep disturbances and changes in the brain.
The research focused on examining sleep factors and biomarkers that measure the health of the brain’s white matter, which is crucial for connecting different brain regions. One of the biomarkers studied was white matter hyperintensities, which are small lesions visible on brain scans. These hyperintensities tend to become more common with age or uncontrolled high blood pressure. The other biomarker measured the integrity of axons, the nerve fibers that facilitate communication between nerve cells.
Diego Z. Carvalho, a study author from the Mayo Clinic, explained that these biomarkers serve as sensitive indicators of early cerebrovascular disease. The study revealed a correlation between severe sleep apnea, reduced slow-wave sleep (also known as non-REM stage 3 or deep sleep), and the presence of these biomarkers. Carvalho emphasized the importance of these findings, stating that as there is currently no treatment for these brain changes, it is crucial to identify ways to prevent or mitigate their progression.
The study involved 140 participants with obstructive sleep apnea, aged on average 73, who underwent brain scans and overnight sleep studies. None of the participants exhibited cognitive issues at the beginning of the study or developed dementia by the study’s end. The severity of sleep apnea varied among the participants, with 34% experiencing mild, 32% moderate, and 34% severe sleep apnea.
The researchers observed that for every 10-point decrease in the percentage of slow-wave sleep, there was an increase in white matter hyperintensities, equivalent to aging by 2.3 years. The same decrease was associated with reduced axonal integrity, akin to aging by three years. Individuals with severe sleep apnea displayed higher volumes of white matter hyperintensities compared to those with mild or moderate sleep apnea, along with decreased axonal integrity in the brain.
Further research is necessary to determine the exact relationship between sleep issues and these brain biomarkers. Additionally, investigations should explore whether improving sleep quality or treating sleep apnea can impact the trajectory of these biomarkers. Nevertheless, these findings emphasize the potential significance of addressing sleep disturbances and their potential implications for brain health and the risk of stroke, Alzheimer’s disease, and cognitive decline.