"Physicians treat memory loss in alcoholic patients with massive amounts of thiamine, or vitamin B1," he added. "We suspect that the dose helps dying cells to recover, enabling the brain to use them again."
The scientists' next step is to determine how sleep apnea causes tissue loss in the mammillary bodies.
Harper hypothesizes that repeated drops in oxygen lead to the brain injury. During an apnea episode, the brain's blood vessels constrict, starving its tissue of oxygen and causing cellular death. The process also incites inflammation, which further damages the tissue.
"The reduced size of the mammillary bodies suggests that they've suffered a harmful event resulting in sizable cell loss," Harper said. "The fact that patients' memory problems continue despite treatment for their sleep disorder implies a long-lasting brain injury."
In a future study, Harper and Kumar will explore whether taking supplemental vitamin B1 helps restore sleep apnea patients' memory. The vitamin helps move glucose into the cells, preventing their death from oxygen starvation.
"UCLA researchers used sophisticated imaging technology to identify brain lesions associated with impaired memory in individuals with obstructive sleep apnea," said Elizabeth G. Nabel, director of the National Heart, Lung and Blood Institute, which funded the study. "These results underscore the importance of early diagnosis and treatment of sleep-disordered breathing, which can have long-term effects on patients' health and well-being."
Obstructive sleep apnea occurs when the muscles in the throat, soft palate and tongue relax during sleep and sag, narrowing the airway. The tongue slides to the back of the mouth, blocking the windpipe and cutting off oxygen to the lungs.
The sleeper wakes up, gasping for air, and falls back into a fitful sleep. The cycle
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University of California - Los Angeles