A groundbreaking study published online in Neurology®, the official journal of the American Academy of Neurology, has uncovered a potential connection between obstructive sleep apnea (OSA) and brain degeneration. The research suggests that OSA may lead to memory-related brain damage due to oxygen deprivation during REM sleep. This phase of sleep is crucial for cognitive functions like memory consolidation. Although the findings indicate a strong association, they do not establish causation. The study highlights the importance of addressing sleep disorders to mitigate potential cognitive decline.

In this investigation, researchers examined 37 individuals with an average age of 73 who did not exhibit signs of cognitive impairment. Participants underwent overnight sleep studies to monitor their oxygen levels throughout all sleep stages, particularly focusing on REM sleep. The team discovered that diminished oxygen saturation during REM was linked to increased white matter hyperintensities in the brain, which are indicative of damaged tissue caused by compromised small blood vessels. Furthermore, these changes were associated with structural alterations in memory-associated regions such as the hippocampus and entorhinal cortex.

The research also explored the relationship between memory performance and brain structure. Participants completed memory assessments before and after sleep, revealing that deficits in sleep-dependent memory correlated with reduced thickness of the entorhinal cortex. According to Dr. Bryce A. Mander from the University of California Irvine, these findings suggest that OSA-induced brain changes might contribute to age-related cognitive decline and conditions like Alzheimer's disease.

White matter hyperintensities emerged as a significant predictor of brain volume changes. Lower minimum blood oxygen saturation levels and extended periods below 90% oxygen saturation were strongly associated with greater white matter hyperintensity volumes. These factors were linked to decreased hippocampal volume and cortical thickness in areas vital for memory processing.

This study provides valuable insights into how sleep apnea could influence cognitive health through its impact on brain structures involved in memory. However, it is essential to consider the limitations, such as the predominantly white and Asian participant demographic, which may restrict generalizability. Supported by the National Institute on Aging and the American Academy of Sleep Medicine Foundation, the findings underscore the need for further exploration into the mechanisms linking sleep disorders and neurodegenerative processes.