A new study in the US has shown a link between older people who suffer hearing loss, and the decline of their brain and dementia.
The study, published in the journal JAMA Internal Medicine, has suggested that it could be due to changes in the brain as hearing declines, and also the social isolation from not being able to communicate as easily.
The researchers at Johns Hopkins University say that if hearing loss is treated, it could slow down the onset of cognitive decline which can lead to dementia.
The study, following just under 2,000 people in their 70’s for six years, showed that result of those with hearing loss had a 24% bigger decline in thinning abilities and declined 40% more quickly.
One of the researchers, Dr Frank Lin, said there were two main theories about how the two could be linked; the first which has been linked previously, is becoming socially withdrawn from hearing loss can lead to cognitive decline. The second is the idea that as the hearing declines, the brain has to work harder to interpret information and therefore is not being used for other functions.
This is a large, long-term, well-conducted study, which means its results are likely to be reliable. There are many reasons why older people with hearing problems may also experience a decline in their thinking abilities. However, even though there is definitely a link, iit does not show that hearing loss causes these problems. We don’t know from the study whether hearing aids can help reduce the chances of thinking problems for people with hearing loss.
Many older people have hearing loss, but this does not mean they will get problems with thinking and memory, although these difficulties are also common in older people. People with hearing loss may find it harder to concentrate because they cannot hear easily, or may feel isolated. These things can make it harder to think properly.
Dr Lin said:
The major public health question is if we treat hearing loss can we delay cognitive decline or dementia? That’s what we all care about, but the answer is we just don’t know.
Dr Eric Karran, from the charity Alzheimer’s Research UK, said the exact connection between hearing loss and cognitive decline was still unknown:
Potential social isolation caused by hearing impairment is a more likely explanation for this link than there being a shared disease process, although this needs further investigation, this will be an interesting area to study further. Many people find their hearing becomes worse as they get older, and age is also the biggest risk factor for dementia.
Understanding whether the two are directly linked could give important insight into the condition, but more research will be needed to fully answer this question.