CPAP use may boost apneics’ memory

A study recently published demonstrates that individuals diagnosed with obstructive sleep apnea (OSA) may have hope of regaining cognitive functions once they begin treatment for the apnea.

Study results, published in the December 2006 issue of CHEST, show the majority of trial participants who suffered memory-impairment prior to treatment demonstrated normal memory performance after three months of optimal continuous positive airway pressure CPAP use.

A CPAP is a medical device, which, in the simplest of terms, is an air generator set to deliver a prescribed, constant flow of air, keeping the airway open and preventing apnea.

The air is delivered through a tube from the CPAP to a mask which is generally worn over the nose, although some people prefer a mask covering both their nose and mouth. The amount of air pressure needed to treat apnea is determined on an individual basis during an overnight sleep study.

Memory improvement varies, based on compliance

The study, conducted at Brown University Medical School, in Providence, RI, also demonstrated that memory improvement varied, but that was based on individual CPAP compliance.

Individuals who used their CPAP for at least six hours a night were nearly eight times as likely to demonstrate normal memory abilities at the end of the three-month trial compared to individuals who used CPAP for less than two hours each night.

“Patients with apnea often complain of daily forgetfulness, such as losing their keys, forgetting phone numbers, or forgetting to complete daily tasks,” said senior study author Mark S. Aloia, PhD, who left Brown after the study, and is now with the National Jewish Medical and Research Center, Denver, CO.

“Where memory is concerned, we may have the ability to reverse some of the impairments by providing effective and consistent use of CPAP treatment,” Aloia explained.

Aloia and colleagues examined the degree to which varying levels of CPAP adherence improved memory in 58 memory-impaired patients with clinically-diagnosed obstructive sleep apnea.

The word “apnea” is Greek, meaning “without breath,” and clinically, a person must stop breathing for a period of at least 10 seconds more than nine times an hour to be classified as having apnea. It isn’t uncommon for apneics to stop breathing hundreds, even thousands of times each night, with some people having more than 60 apneas per hour.

All study participants underwent cognitive evaluation, involving verbal memory testing, prior to starting CPAP. They then repeated the testing at a three-month follow-up visit with the researchers.

Patients were prescribed CPAP machines, but the study doesn’t identify if all machines were at optimal pressures.

The authors wrote in the article that “adherence” or compliance, was “covertly” monitored using internal microprocessors within each device.

Most CPAP devices on the market today have internal memory devices to record and capture information for physicians, including amount of time the device is used each night, if the person had the mask on or if the machine was running but the mask was not on (which would be reported, in most cases, as a “major leak”), how often the individual uses the machine, if the person had any apneas, and other therapeutic information that can be used to help evaluate a person’s compliance, but also ensure the CPAP is delivering appropriate pressures to treat the apnea.

Adjustments to pressure are sometimes necessary to continue effectively treating the apnea. Sometimes the pressure needs to be increased, while other times the pressure needs to be reduced. A pressure too high can cause a different type of apnea, known as central sleep apnea, which, in basic terms, means the brain forgets to breathe. If the pressure is too low, the obstructive sleep apnea is not being effectively treated, which keeps the person at risk of health issues associated with untreated sleep apnea. A combination of central and obstructive apneas is known as mixed sleep apnea.

After treatment was initiated for the study, patients were divided into three groups based on their three-month CPAP adherence. The groups were:

1. poor users (n=14), patients who averaged fewer than 2 hours/night of CPAP use;
2. moderate users (n=25), patients who averaged 2 to 6 hours/night of CPAP use; and
3. optimal users (n=19), patients who averaged more than 6 hours/night of CPAP use.

Comparing memory in compliant vs. non-compliant apneics

“Moderate use of CPAP may help, but it might not allow patients to reach their full potential recovery where memory is concerned, especially if memory is impaired at baseline,” said Dr. Aloia.

At baseline, all patients were found equally impaired in verbal memory, with the average verbal memory score being approximately “two SD” below the mean for all participants. Following three months of CPAP treatment, 21 percent of poor users, 44 percent of moderate users, and 68 percent of optimal users demonstrated normal memory performance.

Compared with poor users, optimal users of CPAP were nearly eight times as likely to demonstrate normal memory abilities.

Overall, the average verbal memory score for all patients improved approximately one SD.

“Moderate use of CPAP may help, but it might not allow patients to reach their full potential recovery where memory is concerned, especially if memory is impaired at baseline,” said Aloia.

“For patients with apnea, the more regularly and consistently they use CPAP, the better off they will be,” Aloia said.

Individuals with apnea, Aloia believes, should use their CPAP machines for at least six hours each night, but also every time they sleep.

Understanding sleep apnea

To understand what happens when a person has one event called an apnea, consider drinking a thick milkshake through a straw. To create a quasi-simulation of an apnea using the milkshake, place the straw at the bottom of the cup containing the milkshake, trying to block the flow of milkshake through the straw. The straw will collapse and twist. That’s basically what happens when a person suffers apneas while they sleep.

Undiagnosed and untreated apnea may lead to a host of health issues, including memory loss, diabetes, heart attack, stroke, high blood pressure, and other ailments.

“Our findings also suggest that this optimal level of CPAP adherence is uncommon following three months of treatment,” said Aloia. “We need to find ways of encouraging patients to use their treatment all night, every night in order to optimize treatment response.”

“CPAP has proven to be an effective treatment for patients with apnea, yet adherence to treatment remains poor,” said Mark J. Rosen, M.D., FCCP, President of the American College of Chest Physicians. “Physicians should educate their patients with apnea about the importance of using CPAP consistently and discuss ways to overcome obstacles to adherence.”

Individuals, whether diagnosed with apnea, or those who suspect they may have apnea, may need to initiate conversations with the physicians about apnea. A consultation with a board-certified sleep specialist may also be appropriate. To find one in your area, visit http://www.absm.org/Diplomates/listing.htm.

If you suspect you or someone you know may have sleep apnea, please consult with a qualified physician familiar with sleep disorders, or, better yet, a sleep specialist, to discuss your concerns.

No information disseminated by Awake in America is intended to replace medical advice, nor is any information to be misinterpreted as an attempt to diagnose, treat, cure, or prevent any disease. If you have questions about any health-related concerns, and need medical advice, please contact a qualified medical professional immediately. This information is intended to provide support, guidance, and encouragement to others contending with the many challenges of sleep disorders. The goals of Awake in America are to support, educate, and inform those who feel the impact of sleep disorders, as well as the general public. Medical advice should come only from qualified, licensed, and trained health-care professionals familiar with your health first-hand, in a face-to-face environment, not via an online forum.