SLEEP APNEA AND BRAIN CHANGES

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Sleep Apnea Linked to Structural Brain Changes: Study

Recent research finds that the condition can lead to changes associated with Alzheimer’s disease when left untreated.

Sleep apnea is more common among overweight people and those suffering from hypertension. Monkey Business Images/Shutterstock
Sleep apnea doesn’t just disrupt your sleep; it may also change brain structures essential for memory, potentially increasing the risk of Alzheimer’s disease.
A new 10-year study of nearly 3,000 older Latino adults has found that people with severe sleep apnea show brain changes, including inflammation in areas critical for memory.
However, research findings regarding sleep apnea’s effects on the brain have varied; some studies have connected sleep disturbances and low oxygen levels to brain shrinkage, while others point to swelling in brain tissues.

How Sleep Apnea Affects Brain Structure

Increasing evidence shows that sleep apnea changes the brain.

The recent study, published in Neurology on Jan. 14, assessed participants’ sleep quality through at-home tests that measured breathing interruptions and blood oxygen levels.
Researchers looked at participants’ brain scans between 2008 and 2012 and then 10 years later. They found that those with the most severe sleep apnea and poor oxygenation during sleep had a larger hippocampus and more white matter lesions. Both changes are linked to elevated risk of poorer cognition and Alzheimer’s disease.
The hippocampus is critical for storing and forming memories. White matter makes up 50 percent of the brain, and lesions in it often signal damaged blood vessels.
The lack of consistent airflow during sleep apnea can lead to such brain damage due to insufficient oxygen.

Chronic low oxygen levels and disrupted sleep patterns in sleep apnea likely cause inflammation, swelling, and vascular damage, placing stress on the brain and potentially leading to neuroinflammation that increase Alzheimer’s risk, lead study author Dr. Alberto R. Ramos of the University of Miami, fellow of the American Academy of Neurology, told The Epoch Times.

Severe sleep apnea is defined as 30 or more breathing interruptions per hour during sleep, while fewer than five interruptions per hour considered normal.

Sleep, Alzheimer’s, and the Fragile Hippocampus

The hippocampus and nearby brain regions are particularly vulnerable to low oxygen levels, as they depend heavily on small blood vessels susceptible to damage during periods of reduced oxygenation during sleep.

This heightened sensitivity makes these areas prone to the effects of Alzheimer’s disease, as they require a continuous supply of energy and are closely linked to other brain regions.
Previous research has noted changes in the hippocampus due to sleep apnea.

A study published in 2018 in NeuroImage: Clinical documented both increases and decreases in hippocampal volume due to obstructive sleep apnea (OSA), the most common type of sleep apnea. The increase in volume was linked to inflammation, while the decrease was associated with tissue loss and shrinkage. A similar finding was reported in a 2022 study that linked severe OSA to an enlarged hippocampus and mild cognitive impairment.

Like sleep apnea, sleep-disordered breathing has been correlated with Alzheimer’s-related brain changes, including higher levels of amyloid, a protein that forms harmful plaques and a hallmark of Alzheimer’s disease.

“While not the study’s focus, our findings align with evidence that untreated sleep apnea may accelerate and cause brain injury that could lead to Alzheimer’s-related changes,” Ramos said.

Sleep, especially deep sleep, is critical for brain health, and is thus protective against Alzheimer’s disease. Conversely, poor sleep can heighten risk. Research shows that the brain’s waste-clearing system—responsible for eliminating harmful substances, including beta-amyloid—functions most effectively during sleep.

The Silent Crisis of Sleep Apnea

“Early diagnosis and treatment are critical to mitigate these effects and protect brain health,” Ramos said.
Around 80 percent to 90 percent of those with sleep apnea don’t know they have it. While loud snoring can often be an indicator, not everyone with sleep apnea snores, and not all snorers have it.

The only definitive way to diagnose sleep apnea is through a sleep study, also known as polysomnography. Common symptoms prompting people to seek evaluation for sleep apnea include daytime sleepiness, sudden awakenings with gasping, memory issues, mood swings, and frequent nighttime urination.
Treating sleep apnea and implementing healthier sleep habits may slow or prevent further brain changes, although it remains uncertain whether existing damage can be reversed.
The most common treatment for sleep apnea is the use of breathing devices, such as a continuous positive airway pressure (CPAP) machine. These devices deliver a steady stream of air to keep airways open during sleep.

Additionally, doctors may recommend oral devices like mouthpieces, which keep the airways open during sleep. In some cases, surgical interventions may be used to improve airway function.

Lifestyle modifications, such as weight loss, quitting smoking, and avoiding sedatives or alcohol, can also enhance sleep quality and potentially reduce the severity of sleep apnea.