Older women who suffer from breathing disorders during sleep – the so-called sleep apnea are about 85 percent. at greater risk of dementia than women without the condition, according to a study published in the Journal of the American Medical Association.
This is the first study to show that sleep apnea may contribute to a decline in mental performance. They show that there is a biological relationship between sleep and cognitive ability, and that treatment of apnea could prevent or delay the development of dementia in older people, comments Kristine Yaffe, researcher, professor of psychiatry, neurology and epidemiology at the University of California, San Francisco.
Sleep apnea (aka sleep apnea syndrome) is a fairly common disorder of breathing during sleep. It is characterized by periodic respiratory arrests, which cause tissue hypoxia (including nerve tissue and heart muscle), fluctuations in blood pressure and an increase in heart rate. People with apnea usually snore loudly and often wake up at night gasping for breath.
Most often, apnea is caused by the upper respiratory tract collapsing during sleep, blocking the flow of air to the lungs. This is called obstructive (obstructive) apnea.
There is scientific evidence that untreated apnea not only causes daytime sleepiness and fatigue, but also increases the risk of heart disease, stroke and diabetes. Previous observations also suggested that it may contribute to the development of dementia.
Scientists from the team of prof. Yaffe conducted a study among 298 seniors with an average age of over 82 years. At first, none of them had symptoms of dementia or apparent deterioration in mental performance.
They all underwent polysomnography at their home. It allows you to measure various physiological parameters during sleep, such as bioelectric brain activity (electroencephalogram), airflow in the airways, respiratory movement rate, eye movement recording (electrooculogram), muscle electrical activity recording (electromyogram), heart rate and oxygenation. blood.
This allowed researchers to assess the rate of apnea (i.e., complete blockage of the airways) and hypopnea (reduction of airflow through the airways by at least 30%), and the length of time women were hypoxic during sleep.
About five years later, the old ladies passed a series of tests to assess their mental performance, memory and speech fluency.
Detailed analysis of the obtained results showed that more than one third of the women (over 35%) developed dementia or had mild mental deterioration.
It also turned out that more often – by 85 percent. – it concerned women suffering from sleep apnea.
As observed by the researchers, the key factor leading to the deterioration of the mental performance of the elderly was hypoxia. Women with more hypoxia or a significant amount of sleep apnea were more likely to develop dementia or mild intellectual decline.
However, no similar relationship was observed with regard to the total duration of sleep and the number of awakenings due to difficulty in breathing.
The researchers recalled that some of the previous studies suggested that oxygen therapy in patients with Alzheimer’s (the most severe form of dementia), as well as in those suffering from apnea, may slow down the decline of mental abilities.
Recent work confirms that oxygen therapy could reduce the risk of dementia or at least delay its development in older people with sleep apnea. (PAP)