Hearing loss and dementia
Are hearing loss and dementia really linked?
There’s been a lot of talk in the papers and on the internet about links between hearing loss and dementia. There were even cases in the past of people being misdiagnosed with dementia when they had hearing loss. This was due to hearing loss being misunderstood. People with hearing loss can sometimes come across as confused, or not understanding what’s being said.
Luckily, thanks to greater awareness and education, this is now rare. However, the link between these two conditions is becoming undeniable.
As if those with hearing loss don’t already have enough to worry about, research shows that those with hearing loss are at higher risk of developing dementia.
The study by scientists at John Hopkins University in Baltimore and the National Institute on Ageing monitored the brain size of participants through annual MRI screening over a ten year period. It is well known that the brain begins to shrink with age. Those with more brain tissue loss are more likely to develop dementia. However this study noted that participants with hearing loss had more brain shrinkage than those with normal hearing.
Each year, those with hearing loss were losing an extra cubic centimetre of brain tissue.
It also found that those with a greater hearing loss were losing the most brain tissue. Putting them at higher risk of developing dementia.
This study and others like it are ongoing. Other studies have found that the brains of hearing and deaf people are different. The area of the brain that processes sound and language in hearing people is smaller in those with severe hearing loss. MRI scans have shown that these areas may be utilised by the brain for other sensory processes such as vision.
One of the suggestions for the extra loss in brain tissue is lack of stimulation. If part of the brain is not being used its natural plasticity will divert energy to other areas.
Another suggestion is that the areas which process sound and language are also involved in processing memory. So as this area shrinks due to hearing loss, memory is also affected.
A popular theory about this link is cognitive overload. People with hearing loss need to concentrate more on everything around them in order to hear. They also rely more on visual cues. It has been suggested that this extra constant effort puts more strain on the brain. Meaning there is less energy left for memory and processing other tasks.
However, it isn’t all doom and gloom. Further research by Isabelle Mosnier from Paris, focussed on patients that received cochlear implants. This study showed that people who received cochlear implants had a slower rate of brain shrinkage than those whose hearing loss went untreated.
Whilst a cause and effect relationship between dementia and hearing loss has yet to be proven, it is clear that the two are related in some way. Whilst not everyone with hearing loss will go on to develop dementia, they are statistically at a higher risk. It is also clear that early treatment of hearing loss can slow the effect of brain shrinkage by keeping the brain’s auditory cortex stimulated and preventing brain overload.
People at high risk of dementia tend to suffer from depression and social isolation. These are also things which effect people losing their hearing. Because it becomes harder and harder to communicate with family and friends many people begin to withdraw. Social activities can be difficult and a deaf person may feel left out, even in a large group of caring friends.
Just as those with dementia worry about embarrassment or people thinking they are mad, those with hearing loss worry about speaking out of turn and people thinking they are silly.
Both groups can give up completely on being socially active, and become very withdrawn and depressed.
Early treatment with hearing aids can help prevent this. The earlier someone gets hearing aids, the easier they are to get used to. Things will seem loud at first because the brain gets used to peace and quiet. But wearing hearing aids can help people maintain an active social life, as well as staying in touch with family and friends.
As the research also showed, those who had their hearing loss treated lost less brain tissue over time, reducing the risks of developing dementia.
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You may be able to hear people but not understand everything they are saying, making you feel out of sync with the conversation. You might get the wrong end of the stick in conversations and get frustrated with people. If the subject changes without