There have recently been reports of a link between untreated sleep apnea and cognitive decline. Here’s the good news: treating sleep apnea can eliminate the detrimental effects of apnea. But what’s happening in the brain? How does sleep apnea treatment actually improve cognitive outcomes? A recent study investigated this issue using two different technologies: structural brain integrity and functional brain connectivity. In other words, the research team investigated each brain region’s “thickness” (thicker typically means better) and how well brain regions communicate with each other (stronger connections are usually better).
This study aimed to focus on “older” adults, meaning only those over 65 years old, who had untreated sleep apnea. To identify these individuals, people entering a sleep lab over the course of a few years underwent an overnight sleep study so that sleep apnea presence and severity could be assessed. Individuals with sleep apnea entered the study.
Each participant then underwent a brain scan for the assessment of structural and functional integrity of the brain. They underwent cognitive functioning tests so that the researchers could determine how “healthy” each brain was. Finally, each participant was given the option to undergo CPAP treatment. Many of the participants began treatment, but many did not. After 3 months of treatment (or no treatment) each participant returned to undergo an additional brain scan and additional cognitive tests. Both sets of tests and brain scans were compared to see whether those who underwent treatment for their sleep apnea fared better than those who did not.
As expected, the participants who were treated performed better on cognitive testing after 3 months of treatment when compared to baseline. Specifically, cognitive domains including memory and executive function (speed of mental processing and mental flexibility) improved. Those who remained untreated did not perform better at the second time point. When comparing brain scans, connectivity was increased in the frontal region (which is responsible for executive functioning). On the other hand, the untreated group was found to have lower brain thickness at follow-up when compared to baseline.
This is an interesting study, as it is a step towards looking into the brain to see what sleep apnea treatment is actually doing. Of note, functional brain connectivity was strengthened in the treatment group, while structural brain integrity actually worsened in the non-treated group. These findings suggest that only 3 months of treatment helps to heal the brain, and only 3 months of sleep apnea without treatment is detrimental for the brain! If you are having doubts about using your treatment, please think about your brain!
Source: Dalmases, M., Solé-Padullés, C., Torres, M., Embid, C., Nuñez, M. D., Martínez-Garcia, M. Á., ... & Montserrat, J. M. (2015). Effect of CPAP on Cognition, Brain Function and Structure among Elderly Patients with Obstructive Sleep Apnea: a Randomized Pilot Study. CHEST Journal.