“We found that people with amyloid plaques who had more severe sleep apneas also were more likely to have lower volumes in the medial temporal lobe area of the brain, including the hippocampus, which plays a role in memory and Alzheimer’s disease,” says study author Geraldine Rauchs, Ph.D. “The people who did not have amyloid plaques did not have this lower brain volume, even if they had severe sleep apneas.”
This study included 122 participants with an average age of 69 years old without memory problems. All of the participants underwent brain scans which revealed that 26 of the participants had amyloid plaques. Additionally, all of the participants took tests of memory and had overnight sleep studies conducted which were repeated after an average of 21 months.
Those with amyloid plaques in their brain who had more severe sleep apnea were found to have lower brain volume in the medial temporal lobe area of the brain, this association may suggest loss of brain cells, and this connection was not found in those without amyloid plaques in their brains.
Overall, lower volumes in the hippocampus at enrollment were associated with lower test scores on episodic memory at the conclusion of the study; and no association was found between sleep apneas at enrollment and memory scores at the conclusion of the study.
“Our results suggest that some people may be more vulnerable to the adverse effects of sleep apnea,” Rauchs said. “People who are in the very early stages of the Alzheimer’s continuum showed a specific vulnerability to sleep apneas. Further studies should look at whether treating sleep-disordered breathing could potentially improve cognition and prevent or delay neurodegeneration.”
It was noted that this study does not prove that sleep apnea causes lower brain volume, it only shows an association. This study was also not without limitations such as the same version of verbal testing was used throughout the study meaning that it is possible that some memory decline may have been minimized due to a familiarity with the testing.
