Dementia, including Alzheimer’s disease, is a serious threat to aging Americans. Not only does it shorten people’s lives, it diminishes the quality of people’s lives and causes distress to their families. There are few promising treatments available, and no cure in sight, so prevention remains our best approach to helping people at risk for this condition.
And it seems that sleep apnea treatment might be a vital part of prevention. A new study shows that sleep apnea is linked to significant brain changes in older individuals with cognitive changes that are considered a sign of impending dementia.
Sleep Apnea’s Impact on the Brain
In this study, researchers recruited 83 individuals from the age of 51 to 88 who were considered at risk for dementia. These individuals had neurospychological testing to determine the level of their cognitive difficulties and magnetic resonance imaging (MRI) to map the structure of their brains. They were also given a full polysomnography to determine the extent of their sleep apnea.
The results were then compared to show that brain changes were strongly linked to the level of sleep apnea in these individuals. The severity of sleep apnea was measured in two different ways: oxygen desaturation (how much the brain is deprived of oxygen during sleep) and sleep disturbance (how much sleep was disrupted by wakenings).
Researchers found that oxygen desaturation was linked to reduced cortical thickness in the bilateral temporal lobes. What does that mean? First, this is a brain change that’s common in people with dementia. Second, the temporal lobes are one of the brain’s important areas for speech and vision processing. Not surprisingly, decreased volume in these areas was associated with increased speech difficulties.
Sleep disturbance was also associated with brain changes, including increased thickness in the postcentral gyrus, pericalcarine, and pars opercularis, as well as increased volume of the hippocampus and amygdala. Some of these changes may be related to the brain’s attempt to provide additional speech processing areas to make up for the brain matter lost elsewhere.
Early Diagnosis and Treatment Is Critical
This study provides us with another piece in the long arc that links sleep apnea to dementia, including Alzheimer’s disease. We have studies performed before the onset of cognitive difficulties that show brain chemical and structural changes that could lead to dementia. And we have other studies showing that sleep apnea is linked to early onset dementia. Now this study shows us that in the early stages of cognitive difficulties, sleep apnea is linked to the brain changes that are linked to those cognitive difficulties. This makes a complete arc between sleep apnea and dementia.
Fortunately, we know that sleep apnea treatment can potentially prevent or delay dementia. But dementia doesn’t develop overnight. Although it’s probably not too late to benefit from sleep apnea treatment once dementia starts, the best benefits come from early diagnosis and treatment of sleep apnea.
If you have been told that you have sleep apnea or have sleep apnea symptoms, it’s important that you get effective treatment early to protect your brain from the damaging effects. It’s also important to remember that oral appliances are as effective as CPAP at treating psychological distress related to sleep apnea.