A new study confirms links between obstructive sleep apnea and Alzheimerís disease, possible reasons for the association include the buildup of toxic products due to lack of oxygen.
In obstructive sleep apnea, a personís breathing repeatedly stops and restarts. Symptoms include loud snoring, restless sleep, and sleepiness during the day.
Estimates of the conditionís prevalence among adults in the general population vary widely, from 9ñ38%. However, sleep apnea is typically more common among males, older people, and individuals with obesity.
Sleep apnea has links to poor attention, memory, and executive skills, and is a recognized risk factor for the development of dementia.
We know that if you have sleep apnea in mid-life, youíre more likely to develop Alzheimerís when youíre older and if you have Alzheimerís, you are more likely to have sleep apnea than other people your age.
The connection is there, but untangling the causes and biological mechanisms remains a huge challenge.
By studying postmortem samples from people who had sleep apnea, the researchers recently discovered that the severity of the condition correlates with reductions in the volume of the hippocampus.
This part of the brain, which is closely involved in memory, also atrophies in people with Alzheimerís.
Using the same brain samples, the team of researchers have now found the first evidence of amyloid plaques associated with sleep apnea.
Amyloid plaques are a hallmark of the damage seen in Alzheimerís, together with clumps of fibers known as neurofibrillary tangles.
The researchers discovered that the plaques appear first in the same locations and spread in the same way in the brains of people with sleep apnea as they do in people with Alzheimerís.
In addition, the extent of the plaques correlated with the severity of sleep apnea.
ìItís an important advance in our understanding of the links between these conditions and opens up new directions for researchers striving to develop therapies for treating and hopefully preventing Alzheimerís disease,î says Prof. Robinson, who led the research.
The scientists investigated preserved brain samples from 34 people with a mean age of 67 years who had received a diagnosis of obstructive sleep apnea. Brainstems were available for study from 24 of these individuals.
