Obstructive Sleep Apnoea (OSA) is a potentially dangerous sleep disorder, which is characterised by the repeated stopping and starting of breathing in sleep. It can often lead to serious complications and needs medical attention as early as possible. A new study published in the European Lung Journal now names dementia as one of the consequences of OSA.
In OSA the walls of the throat relax and narrow during sleep, which causes obstruction in breathing. This results in reduced levels of oxygen in the blood. The study says that the reduction of oxygen in the blood leads to the shrinking of brain’s temporal lobes, which affects the memory.
The researchers who conducted the study says that it provides evidence that older people with sleep apnoea should be screen and given treatment for dementia. Professor Sharon Naismith from the University of Syndey, Australia said that between 30-50 percent of the risk for dementia in sleep apnoea is due to modifiable factors: depression, high blood pressure, obesity and smoking. The researchers have found that various sleep disturbances are also risk factors for dementia. “We wanted to look specifically at obstructive sleep apnoea and its effects on the brain and cognitive abilities,” Professor Naismith adds.
A group of 83 people, aged between 51 and 88 years, who visited their doctor over declining memory or mood, with no OSA diagnosis were studied. They were each assessed for their memory skills and symptoms of depression. A MRI scan was taken to measure the dimensions of the different areas of thebrain.
They also attended a sleep clinic where signs of OSA were monitored, recording brain activity, oxygen levels, heart rate, breathing and movements. The researchers found that patients with low levels of oxygen in their blood tended to have reduced thickness in the left and right temporal lobes of the brain. These regions were also known to be important for memory.
They also found that this change in the brain was linked to the person’s poor ability to learn new information. It is the first time such a link has been shown through research. The patients who had signs of OSA were also more likely to have increased thickness in certain regions of the brains, which could be a sign of the brain reacting to low levels of oxygen with swelling or inflammation.
Professor Nainsmith and her team are now researching ways to find out whether continuous positive airway pressure (CPAP) treatment can prevent further damage to the brain of the OAS affected patients.