A recent study published in Neurology® on May 7, 2025, has found a strong association between obstructive sleep apnea (OSA) and damage to brain regions critical for memory. OSA is a condition in which breathing repeatedly stops and starts during sleep due to airway blockage. This disruption leads to lowered oxygen levels, especially during rapid eye movement (REM) sleep—the phase linked to dreaming and memory consolidation.
Researchers observed 37 older adults (average age 73), none of whom had cognitive impairments or were taking sleep medications. Among them, 24 participants were diagnosed with obstructive sleep apnea. Each underwent overnight sleep studies and brain scans. The results showed that lower oxygen levels during REM sleep were significantly linked to an increase in white matter hyperintensities—bright spots on brain imaging that indicate small vessel damage in the brain.
The study also looked at memory-related brain structures, specifically the hippocampus and the entorhinal cortex. Participants with more white matter hyperintensities showed reduced hippocampal volume and thinner entorhinal cortex—both signs of brain degeneration. Additionally, those with thinner entorhinal cortices performed worse on memory tests taken before and after sleep, suggesting that disrupted sleep might impair memory consolidation.
Although the study does not prove a direct cause-and-effect relationship, the findings suggest that oxygen deprivation caused by sleep apnea may lead to structural brain changes associated with cognitive decline and even conditions like Alzheimer’s disease.
Researchers noted limitations, including the small and demographically narrow sample size, but emphasized the potential implications for aging populations.
Lead author Dr. Bryce Mander concluded that these findings may help explain how OSA contributes to cognitive aging and highlighted the importance of diagnosing and treating sleep apnea to protect brain health.
