According to a new study, people with sleep apnea experience physical damage to parts of the brain involved in memory. Sleep apnea occurs when the muscles in the throat, soft palate and tongue relax and block or reduce airflow to the lungs. The sleeper then wakes up, gasps for air, and then falls back asleep. This cycle can be repeated hundreds of times a night.

Sleep apnea has also been implicated as a risk factor for stroke, heart disease and diabetes.

The findings show impaired breathing during sleep can lead to a serious brain injury that disrupts memory and thinking, according to principal investigator Ronald Harper, professor of neurobiology at the David Geffen School of Medicine at UCLA.

The UCLA study used MRI technology to scan the brains of 43 sleep apnea patients, focusing on what are called mammillary bodies.

These are a pair of small round structures located at the base of the brain that are involved in processing memory. When researchers compared the results to MRI scans of 66 control subjects, they discovered that the sleep apnea sufferers' mammillary bodies were significantly smaller.

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

The next step will be to determine exactly how sleep apnea causes this tissue loss. Researchers will also test to see whether taking vitamin B1 helps restore memory in sleep apnea sufferers.

The study is reported in the June 27 edition of the journal Neuroscience Letters.