A neuroimaging study is the first to show that white matter damage caused by severe obstructive sleep apnea can be reversed by continuous positive airway pressure therapy.
The results underscore the importance of the “Stop the Snore” campaign of the National Healthy Sleep Awareness Project, a collaboration between the Centers for Disease Control and Prevention, the American Academy of Sleep Medicine, the Sleep Research Society, and other partners.
Results show that participants with severe, untreated sleep apnea had a significant reduction in white matter fiber integrity in multiple brain areas. This brain damage was accompanied by impairments to cognition, mood, and daytime alertness.
Although three months of CPAP therapy produced only limited improvements to damaged brain structures, 12 months of CPAP therapy led to an almost complete reversal of white matter abnormalities. Treatment also produced significant improvements in nearly all cognitive tests, mood, alertness, and quality of life.
“Structural neural injury of the brain of obstructive sleep apnea patients is reversible with effective treatment,” said principal investigator and lead author Vincenza Castronovo, Ph.D., a clinical psychologist at the Sleep Disorders Center at San Raffaele Hospital and Vita-Salute San Raffaele University in Milano, Italy. “Treatment with CPAP, if patients are adherent to therapy, is effective for normalizing the brain structure.”
The study results are published in a September issue of the journal Sleep.
“Obstructive sleep apnea is a destructive disease that can ruin your health and increase your risk of death,” said American Academy of Sleep Medicine President Dr. Timothy Morgenthaler, a national spokesperson for the Healthy Sleep Project. “Treatment of sleep apnea can be life-changing and potentially life-saving.”
What is Obstructive Sleep Apnea?
Obstructive sleep apnea (OSA) is the most common form of sleep apnea and is believed to affect approximately 4% of men and 2% of women. However, it is believed that only about 10% of people with OSA seek treatment leaving the majority of OSA sufferers undiagnosed.
Obstructive sleep apnea is caused by a partial or complete blockage of the airways during sleep. During sleep, a person's throat muscles relax allowing the tongue and/or fatty tissues of the throat to fall back into the airways and block airflow.
During an apnea, event air is restricted from moving beyond the obstruction reducing blood flow to the brain. This in turn signals the brain to partially awaken from sleep to signal the body that it needs to breathe.
This is often followed by loud gasping, choking, or snorting sounds as the person takes a deep enough breath to fight past the obstruction.
Once a breath is taken the brain returns to sleep, and the process begins once again. This process can occur just a few times a night or hundreds of times a night depending on the severity of the condition.
Mild OSA- The sufferer experiences 5-14 episodes of interruptions in breathing in an hour.
Moderate OSA- The sufferer experiences 15-30 episodes of interruptions in breathing in an hour.
Severe OSA- The sufferer experiences 30 or more interruptions in breathing in an hour.
Other symptoms of obstructive sleep apnea include:
Snoring that is loud, disruptive, and regular is one of the most obvious signs of potential OSA.
Frequent breaks in breathing caused by an obstruction. These cessations are often followed by choking or gasping noises as the body's respiratory system fights through the blockage.
Excessive daytime sleepiness is caused by frequent interruptions of sleep.
Morning Headaches stem from the loss of oxygen in your bloodstream that flows to your brain as a result of irregular breathing at night.
Restless sleep. Sufferers of obstructive sleep apnea often have fitful sleep as their mind and body are constantly awakened throughout the night, pulling them out of the much-needed stages of non-REM and REM sleep.
Depression or irritability. Lack of regular quality sleep can wreak havoc on a person's mental well-being. Sufferers of obstructive sleep apnea often find themselves feeling short-tempered, and in time it can lead to more severe symptoms of depression.
Causes and Risk Factors
Weight- In many cases, a person's body weight is directly linked to having obstructive sleep apnea. People who are overweight or obese are more likely to have sleep apnea than those that maintain a healthy weight. Sleep apnea can often be caused by excess fatty tissues that become built up in the neck and throat. This can lead to restrictions in airflow as the upper respiratory system's pathway is narrowed or pinched off during sleep.
Age- As people age, their muscles begin to lose muscle tone. This is also true of the muscles in the throat. As throat muscles lose definition, they become weaker and more likely to collapse into the airways during sleep.
Enlarged tonsils or adenoids are the leading cause of obstructive sleep apnea in children but can also affect adults who never had a tonsillectomy when they were younger.
Natural causes- Some people can be genetically predisposed to having a narrower throat or may have an enlarged tongue that falls back into their airway. If your family has a history of OSA you are more likely to have it yourself.
Frequent alcohol use- Alcohol relaxes the muscles in the body, and this includes the throat muscles as well which may relax to the point of blocking the airway during sleep.
Smoking- Smoke is an irritant to the lungs, throat, and esophagus. It can cause inflammation and fluid retention in the upper airways that can impede airflow.
The “Stop the Snore” campaign was launched recently to encourage people to talk to a doctor about the warning signs for sleep apnea, which afflicts at least 25 million adults in the U.S. Sleep apnea warning signs include snoring and choking, gasping, or silent breathing pauses during sleep. Pledge to stop the snore at stopsnoringpledge.org.
The study involved 17 men with severe, untreated obstructive sleep apnea who had an average age of 43 years. They were evaluated at baseline and after both three months and 12 months of treatment with CPAP therapy.
At each time point, they underwent a neuropsychological evaluation and a diffusion tensor imaging examination. DTI is a form of magnetic resonance imaging that measures the flow of water through brain tissue.
Participants were compared with 15 age-matched, healthy controls who were evaluated only at baseline.
A previous study by Castronovo’s research team found similar damage to gray matter volume in multiple brain regions of people with severe sleep apnea.
Improvements in gray matter volume appeared after three months of CPAP therapy. According to the authors, the two studies suggest that the white matter of the brain takes longer to respond to treatment than the gray matter.
“We are seeing a consistent message that the brain can improve with treatment,” said co-principal investigator Mark Aloia, Ph.D., Associate Professor of Medicine at National Jewish Health in Denver, Colorado, and Senior Director of Global Clinical Research for Philips Respironics, Inc. “We know that PAP therapy keeps people breathing at night, but demonstrating effects on secondary outcomes is critical, and brain function and structure are strong secondary outcomes.”
The study was supported by the Respironics Foundation and performed in collaboration with the Center of Excellence in High-Field Magnetic Resonance Imaging at Vita-Salute San Raffaele University.
About the National Healthy Sleep Awareness Project
The Healthy Sleep Project addresses the sleep health focus area of Healthy People 2020, which provides science-based, 10-year national objectives for improving the health of all Americans. The sleep health objectives are to increase the medical evaluation of people with symptoms of obstructive sleep apnea, reduce vehicular crashes due to drowsy driving and ensure more Americans get sufficient sleep. For more information, visit projecthealthysleep.org.
What to do Next
If you're an Alaskan resident and you believe that you may have symptoms of sleep apnea, schedule a free 10-minute phone consultation with one of our clinical sleep specialists. In just 10 minutes we can help you discover whether or not your symptoms warrant a sleep study to help you get diagnosed and treated for your sleep disorder.