Apnea and Accumulation

Sleep apnea may mean you’re not getting good sleep each night; it could also mean you have a higher risk of developing Alzheimer’s disease, according to a 2019 study.

The research, presented at the American Academy of Neurology’s 71st Annual Meeting in Philadelphia in May 2019, shows that those who stop breathing during sleep could have higher levels of an Alzheimer’s disease biomarker known as tau in the area of the brain that helps with memory.

Obstructive sleep apnea, the most prevalent form of the condition, is characterized by periods in which breathing becomes stopped during sleep.

‘Periods without oxygen, called apneas, can happen dozens to hundreds of times during sleep,’ said Dr. Richard Armstrong of Legends Dental in Waco, Texas.

Tau is a protein that forms into tangles. It is commonly found the brains of people with Alzheimer’s disease.

‘Most healthy individuals have five or fewer apnea episodes each hour during sleep,’ Armstrong said.

When apneas occur more often, it is a cause for concern.

‘Repeated interruptions in breathing can mean links to chronic illness, including diabetes, heart disease and high blood pressure,’ Armstrong said.

The research study had 288 participants age 65 and older who did not have cognitive impairment. Bed partners of the participants were asked whether they had ever noticed episodes in which their partner stopped breathing during sleep.

The participants in the study all underwent positron emission tomography (PET) brain scans to find out if the accumulation of tau tangles existed in the brain’s entorhinal cortex area. This cortex is located in the temporal lobe. It is more likely to accumulate tau protein tangles than other parts of the brain.

The entorhinal cortex is an area of the brain that helps manage memory, navigation and time.

Of the 288 participants, researchers identified that 43 individuals (15 percent) have bed partners who witnessed them stop breathing during sleep.

They found that those who did stop breathing during sleep had on average 4.5 percent higher levels of tau in the entorhinal cortex than those who did not stop breathing when sleeping.

The researchers took int account other factors that could contribute to higher levels of tau in the brain, including age, sex, education, cardiovascular risk factors and other sleep complaints.

The researchers believe that sleep apnea does affect tau accumulation in the brain but theorize that higher levels of tau in the brain could contribute to the development of sleep apnea. Their hope is that future research can help determine which situation is the root cause.

The National Institutes of Health supported the study.

Source: American Academy of Neurology. ‘Sleep apnea may be linked to higher levels of Alzheimer’s biomarker in brain.’ ScienceDaily, 3 March 2019.