December 29, 2008
Sleep apnea, a breathing disorder that affects some 20 million Americans, may be a problem for people with Alzheimer's, too. And treatment to ease the condition can have benefits for those struggling with dementia, a new study shows.
Sleep apnea occurs when the soft tissues at the back of the mouth and throat relax excessively during sleep, causing the airways to become blocked and breathing to stop. People with the condition often snore loudly and can wake up hundreds of times during the night, leading to daytime grogginess and fuzzy thinking.
The condition may be particularly prevalent in people with Alzheimer's disease, with some estimates as high as 70 to 80 percent. And earlier research has shown shown that elderly patients with dementia -- particularly those with Alzheimer's disease -- suffered more severe symptoms from sleep apnea, including frequent awakenings, than sleep apnea patients without dementia.
The most effective treatment for the condition is to wear a special mask over the face and nose during sleep that delivers a steady stream of air. The treatment, known as CPAP, for continuous positive airway pressure, can be cumbersome, but it is effective for relieving symptoms.
In the current study, researchers at the University of California, San Diego, School of Medicine and the Veterans Affairs San Diego Healthcare System, found that men and women with Alzheimer's who suffer from sleep apnea got benefits from using a CPAP device. The treatment appeared to improve thinking skills in these patients. In addition, they seemed relatively able to accept using the treatment. The findings appeared in the November issue of the Journal of the American Geriatrics Society.
"Although it is unlikely that obstructive sleep apnea causes dementia, the lowered oxygen levels and sleep fragmentation associated with the condition might worsen cognitive function," said Sonia Ancoli-Israel, Ph.D., professor of psychiatry at the university and the study leader. "This study, which showed significant improvement in patients' neurological test scores after treatment with CPAP, suggests that clinicians who treat patients with Alzheimer's disease and sleep apnea should consider implementing CPAP treatment."
"Any intervention that improves cognition in patients with Alzheimer's disease is likely to result in greater independence for the patient and less burden on their caretakers," said co-author Jody Corey-Bloom, M.D., Ph.D., professor of neurosciences at U.C. San Diego. She added that earlier research had shown that CPAP also reduced daytime sleepiness, a common complaint for Alzheimer's patients.
In the study, participants were randomly assigned to receive either therapeutic CPAP for six weeks, or a placebo CPAP for three weeks followed by therapeutic CPAP for an additional three weeks. Both groups received a complete battery of memory and thinking tests before treatment, at three and at six weeks.
"The change in scores for individual tests suggested improvements in verbal learning and memory as well as some aspects of executive function such as cognitive flexibility and mental processing speed," said Dr. Ancoli-Israel. Earlier studies have also shown that people with Alzheimer's are able to tolerate CPAP.
People with Alzheimer's aren't the only ones who can benefit from CPAP therapy. Earlier studies have shown that CPAP relieves fatigue and improves memory and thinking for anyone with sleep apnea. And a study earlier this year showed that untreated, people with sleep apnea showed long-term damage to brain structures critical for thinking and memory.
"The severity of these sleep disruptions may parallel the decline in cognitive functioning seen in elderly patients with Alzheimer's disease," said Dr. Ancoli-Israel. "While CPAP by no means treats the underlying cause of Alzheimer's disease, by improving patients' sleep patterns, the hope is that their overall cognitive functioning can also improve."
Source: University of California, San Diego