The Correlation between Sleep Apnea and Dementia


Obstructive sleep apnea is one of the most common sleep disorders in the U.S. It occurs when a person’s breathing is interrupted because the walls of the throat relax and constrict while sleeping – it often causes snoring. The body can recover from this constricting position and start breathing again, but some with untreated sleep apnea can pass away in this manner.

While things like changing your window treatments or getting a new mattress can cure many sleep problems, sleep apnea must be diagnosed and treated by a health professional. Most cases are treated successfully, and patients report a better night’s rest.

However, recent research has revealed that those with sleep apnea might not be off the hook. In fact, it could increase your risk of developing dementia.

The University of Sydney performed a groundbreaking study on the long-term impact of sleep apnea. They studied 83 people between the ages of 51 and 88 who had concerns about memory loss with no previous signs of sleep apnea.

Study performers tested each participant for memory loss and depression. They also gave them MRIs to measure different parts of the brain and scope out the degeneration occurring there.

After gaining control data through these tests, researchers began observing signs of obstructive sleep apnea through a polysomnographer. This device measures the oxygen levels, heart rate, breathing, and brain activity.

The analysis of the polysomnography showed that those exhibiting symptoms of sleep apnea were getting less oxygen to their left and right temporal lobes, the areas of the brain responsible for memory function, and the degeneration of them is what leads to the onset of dementia.

This is the first study in which sleep apnea and dementia have been clearly linked.  

Because this is the first study showing this link, further research will be required to identify other risk factors. For example, we don’t know if sleep apnea only leads to dementia in those who already have memory concerns or if it can begin in children with untreated sleep apnea.

But one thing is certain: If the findings in this study are true, more medical professionals should screen for sleep apnea in older patients.

“We chose to study this group because they are older and considered at risk of dementia. Our results suggest that we should be screening for OSA in older people,” encourages Naismith in the conclusion of the study. “We should also be asking older patients attending sleep clinics about their memory and thinking skills, and carrying out tests where necessary,” said Naismith.

Dementia cannot be cured as of now, but sleep apnea is effectively treatable. Those experiencing symptoms of sleep apnea should be examined.

“Between 30 and 50 percent of the risk for dementia is due to modifiable factors, such as depression, high blood pressure, obesity, and smoking. In recent years, researchers have recognized that various sleep disturbances are also risk factors for dementia. We wanted to look specifically at obstructive sleep apnea and its effects on the brain and cognitive abilities,” said Professor Sharon Naismith from the University of Sydney, the lead researcher on the study.

Sleep apnea is typically cured with continuous positive airway pressure (CPAP). It involves wearing a mask over your nose and/or mouth while you sleep to keep your airways open and stop snoring. There are dozens of models of this sleep aid, some more comfortable and effective than others. Patients are encouraged to find a model that will allow them to sleep comfortably while keeping airways open.

While this is the first study to directly associate sleep apnea with dementia risk, it’s not the only publication showing the connection between sleep and memory loss. Many studies have shown that an interruption of REM sleep could increase your risk for dementia.

A notable study was performed by Swinburne University of Technology in Australia. They examined the sleep patterns of 321 participants at an average age of 67. They measured their sleep cycles and collected data for 12 years to understand the connection between sleep and dementia. Of the 321 participants, 32 were diagnosed with dementia and 24 had Alzheimer’s disease.

In examining the participant’s sleep, researchers saw that those who developed dementia spent only 17 percent of their sleep time in REM while those who stayed mentally sound spent 20 percent of their time in REM.

They also showed that with every percent less time they spent in REM, they had a nine percent increase in dementia risk.

“Our findings point to REM sleep as a predictor of dementia,” said Matthew, P. Pase, Ph.D. and study author. “The next step will be to determine why lower REM sleep predicts a greater risk of dementia. By clarifying the role of sleep in the onset of dementia, the hope is to eventually identify possible ways to intervene so that dementia can be delayed or even prevented.”

With this clear connection between dementia risk and poor sleep, it shouldn’t be surprising that there’s a connection between dementia and sleep apnea. When snoring and sleep apnea symptoms wake you from a deep sleep, you’re getting less time in REM.

Further research will be completed to show connections between sleep disorders and dementia in the future, but for now, the need for more sleep-related screenings to decrease dementia risk in the elderly is clear.


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