Obstructive sleep apnea (OSA) is a condition in which a person’s breathing is repeatedly interrupted during sleep. Sleep apnea is quite common; over 22 million Americans suffer from it.
The most common form of dementia, Alzheimer’s disease, affects up to 70% of all people with dementia – age being a major factor for developing the disease.
New research led by RMIT University has established long-suspected connections between sleep apnea and Alzheimer’s disease, finding matching brain damage signs in both conditions.
The study of autopsied brain tissue shows how the start and spread of amyloid plaques in the brain of an Alzheimer patient is similar to that of a sleep apnea patient. Especially in mild sleep apnea cases, plaques and tangles were found in the cortical area near the hippocampus. This is precisely where they are found first in Alzheimer’s disease. Though the two conditions are related, the connection between the two is yet to be established.
Additionally, the study also indicated that though both plaques and tangles were found in the brains of people with sleep apnea, the plaques showed a stronger connection with acute sleep apnea.
Researchers hypothesize that sleep apnea could accelerate the onset of Alzheimer’s disease. It is a known fact that deep sleep clears the brain of toxic proteins. Nevertheless, people suffering from sleep apnea may not successfully reach deep sleep stages due to the distractions caused by interrupted breathing phases. This might hasten the onset of Alzheimer's disease as per the current hypothesis.
The clinical study by Icelandic and Australian scientists is published in the journal Sleep.
Experts from the research believe that you are more likely to develop Alzheimer’s when you get older if you have sleep apnea in mid-life. However, if you have Alzheimer’s, you are more likely to have sleep apnea than other people of your age.
This new research helps to understand the connection between the two conditions. It is significant for researchers striving to develop therapies for treating and preventing Alzheimer’s disease.
The investigation was focused on the hippocampus and the brainstem, two regions known for early detection of pathogenic signs of Alzheimer’s. The researchers looked for signs of the two primary pathological indicators of Alzheimer’s – amyloid plaques and neurofibrillary tau tangles.
The study observed the volume of amyloid present in the hippocampus indicated the gravity of sleep apnea in a given subject. Additionally, tau and amyloid were found in the brainstem samples. However, no parallels could be drawn with sleep apnea severity.
The standard approach to treat moderate to severe sleep apnea with continuous positive airway pressure (CPAP) made no difference to the volume of plaques found in the brain.
Though it is still early to make any claims in this research sector, the new study solidifies the understanding of the links between sleep apnea and cognitive decline. It is quite clear that Alzheimer’s disease and sleep apnea contribute to neurodegeneration. However, how to translate the findings into clinical treatments to prevent cognitive decline is yet to be determined.
Research indicates that the subjects showed no clinical symptoms of dementia before death, suggesting they may have been in an early pre-dementia stage.
While some people may have had mild cognitive damage or undiagnosed dementia, nobody had symptoms that were strong enough for an official diagnosis. However, as per the research, some of the research subjects had a density of plaques and tangles that were sufficiently high to qualify as Alzheimer’s disease.
Experts conducting the study believe that the next stage for the research will be to continue analyzing these samples to understand the neuropathology fully. This would include signs of inflammation and changes to the blood vessels that supply nutrients to the brain. Since the sample size for this study was limited, researchers would prefer to establish clinical research with a larger group for future endeavors.
If you want to treat obstructive sleep apnea (OSA) or have other dental health issues, let our team of dentists in West Des Moines help you.