Sleep Apnea Linked to Memory Loss

WEDNESDAY June 11, 2008 -- People with sleep apnea show tissue loss in brain regions that help store memory, a University of California, Los Angeles (UCLA) study shows.

"Our findings demonstrate that impaired breathing during sleep can lead to serious brain injury that disrupts memory and thinking," principal investigator Ronald Harper, a professor of neurobiology at the David Geffen School of Medicine at UCLA, said in a prepared statement.

People with sleep apnea stop breathing and awaken repeatedly during the night, leading to chronic daytime fatigue and memory and concentration problems. Research has linked sleep apnea to an increased risk of stroke, heart disease and diabetes.

In this study, the UCLA team used MRI to scan the brains of sleep apnea patients. The researchers focused on brain structures called mammillary bodies, located on the underside of the brain.

The study found that the mammillary bodies of the 43 sleep apnea patients were almost 20 percent smaller than those in 66 people without sleep apnea. The results will be published in the June 27 issue of Neuroscience Letters.

Repeated drops in oxygen experienced by sleep apnea patients may lead to brain injury, Harper suggested. He noted that lack of oxygen during an apnea episode can cause brain cell death.

"The reduced size of the mammillary bodies suggests that they've suffered a harmful event resulting in sizable cell loss. The fact that patients' memory problems continue despite treatment for their sleep disorder implies a long-lasting brain injury," Harper said.

"The findings are important, because patients suffering from memory loss from other syndromes, such as alcoholism or Alzheimer's disease, also show shrunken mammillary bodies," lead author Rajesh Kumar, an assistant researcher in neurobiology, said in a prepared statement.

"Physicians treat memory loss in alcoholic patients with massive amounts of thiamine, or vitamin B1. We suspect that the dose helps dying cells to recover, enabling the brain to use them again," Kumar said.

He and Harper plan to study whether taking supplemental vitamin B1 can help restore memory in sleep apnea patients. The vitamin moves glucose into cells, which prevents their death from oxygen starvation.

More information

The American Academy of Family Physicians has more about sleep apnea.

Posted: June 2008


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