Wednesday, December 10, 2014
A new study by the Pacific Health Research and Education Institute in Honolulu has found that elderly patients who spend less time in deep ‘slow wave’ sleep are significantly more likely to lose brain cells than those who sleep more deeply. The research also showed that the lack of oxygen caused by obstructive sleep apnea, a common condition marked by snoring, increases the risk of the small areas of brain damage linked to the development of conditions such as Alzheimer’s. Researchers say that it is not yet clear whether the early stages of dementia are causing poor sleep quality, or if the lack of deep wave sleep is exacerbating the disease process.
The study, published in the online edition of the journal Neurology, involved 167 Japanese American men from Hawaii with an average age of 84 who had sleep tests conducted at their homes. After death, post mortem examinations were conducted on their brains to look for changes such as loss of neurons and ‘micro infarcts’ - areas of dead tissue caused by oxygen starvation. These can be triggered by obstructive sleep apnea (OSA); a condition in which the airway repeatedly becomes blocked, often waking sufferers as they struggle for breath.
The men who had the worst oxygen levels during sleep were four times more likely to have brain damage caused by micro infarcts. Of the 37 men who spent the least time in slow wave sleep, 17 had brain cell loss compared with only seven of the 38 who spent the most time in slow wave sleep. The results remained the same after accounting for factors such as smoking and body weight, and excluding those who died early in the follow-up period. However, the study found no association between poor sleep and the brain plaques that are a hallmark of Alzheimer’s disease.
Researchers say that the findings suggest that low blood oxygen levels and reduced slow wave sleep may contribute to the processes that lead to cognitive decline and dementia. More research is needed to determine how slow wave sleep may play a restorative role in brain function and whether preventing low blood oxygen levels may reduce the risk of dementia.
A separate study earlier this week showed that brains of healthy people who were sleepy during the day contained higher levels of a toxic protein called beta-amyloid, which is also linked to Alzheimer’s: some of those having scans were as young as 50 and none had memory problems.
A good night’s sleep is important for proper brain function in the short term. For more information on the treatment of OSA and snoring, visit us online at HoustonSleep.net