Sleep Apnea May Lead To Memory Loss

An American study has found a direct relationship between sleep apnea and memory loss. According to researchers, sleep apnea patients show tissue loss in brain regions that help store memory.

The team of researchers from University of California at Los Angeles (UCLA) said that the study focuses on the significance of early detection of the disorder. In United States only, nearly 20 million people are affected by sleep apnea which is a major cause of stroke, heart disease, diabetes and sleep-related car accidents.

Apnea is a Greek word which means ‘want of breath’. Sleep apnea is the medical term used for interruptions in breathing during sleep. In sleep apnea, breathing repeatedly stops and starts during sleep, each pause in breathing typically lasts ten to 20 seconds or more. These pauses can occur twenty to 30 times or more in an hour.

A person with sleep disorder may experience irritability, mood swings, impotence or reduced libido, frequent sensation of urinating at night and a reduction of intellectual ability.

The most common kind of sleep apnea is obstructive sleep apnea (OSA), which means a person is not able to get enough air through his mouth and nose into his lungs. Due to this, the amount of oxygen in his blood may dip. And, he may resume normal breathing with the sensation of choking. People with sleep apnea often snore loudly. However, not everyone who snores has sleep apnea.

Principal investigator of the study, Ronald Harper, professor of neurobiology at the David Geffen School of Medicine at U.C.L.A. said, “Our findings demonstrate that impaired breathing during sleep can lead to a serious brain injury that disrupts memory and thinking,”

The scientists looked at the brain scan using magnetic resonance imaging (MRIdefine) of 43 patients suffering from sleep apnea, concentrating on structures on the underside of the brain called as mammillary bodies. They found that the brain structures of subjects were twenty percent smaller, especially on the left side than those without sleep apnea.

Researchers made the hypothesis that continuous drops in oxygen experienced by sleep apnea patients may lead to brain injury.

Harper said, "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."

These are the same structures which are known to be shrunken in patients suffering from memory loss related to other syndromes, such as alcoholism or Alzheimer's disease.

Lead author, Rajesh Kumar and Harper said that in their future study they will explore whether taking supplemental vitamin B1 helps restore sleep apnea patients' memory. The vitamin helps by moving glucose into cells and preventing cell death.

The findings of the study will appear in the June 27 issue of the journal Neuroscience Letters.

A previous study by the researchers from the Woolcock Institute of Medical Research showed that moderate to severe sleep apnea raises the risk of all-cause mortality.