Hearing loss and dementia

Can hearing aids help prevent dementia?

Research into ageing has shown links between dementia and hearing loss. According to researchers at John Hopkins University in Baltimore and the National Institute on Ageing, people with hearing loss lose more brain matter each year than those with normal hearing.

They studied MRI scans taken over the course of 10 years to see how the brain shrinks as it ages. These scans clearly showed that the participants with hearing loss were losing an extra cubic cm each year than hearing participants. It also showed that the greater the hearing loss, the greater the loss of brain tissue.

The areas most affected by tissue loss are the parts of the brain dedicated to auditory processing.

Some specialists have said that this is not surprising. If part of the brain is unused it will begin to waste away, just like any other part of the body. Other scans have shown that the brains auditory processors become utilised by the visual part of the brain. This makes sense as people with hearing loss rely more on visual cues for communication.

Researchers have also suggested that the part of the brain responsible for auditory processing is also used in retaining information and working memory. If this area is shrinking then that would account for the link between hearing loss and dementia.

Another suggestion for the link is cognitive overload. Everyday activities and communication become much harder when you can’t hear. This extra effort by the brain becomes exhausting over time and the brain has less energy for other processing tasks, such as memory.

Social factors also play a part in dementia. People who suffer from depression and become socially isolated are more at risk of developing dementia. So it’s possible that people who become socially isolated or depressed through their hearing loss become part of that high risk group.

So how can hearing aids help?

Isabelle Mosnier from Paris carried out further research in this area. Alongside other researchers she studied the effects of cochlear implants on brain shrinkage. A cochlear implant works as a replacement for damaged nerve cells in the inner ear. Together with an external sound processor they work to give sound to people with profound hearing loss.

Their study found that patients who received a cochlear implant had a slower rate of brain shrinkage than those who had no hearing treatment. Their rate of memory loss also slowed.

The brain cannot re grow parts that are damaged or lost. Once it’s gone, it’s gone. So the evidence that the rate of tissue loss can be slowed down is very significant.

It suggests that by treating hearing loss we can also delay the onset of dementia.

The social aspects of this are clear. By wearing aids for their hearing loss people can stay socially active. They have more confidence when speaking to others and are much less likely to become withdrawn. Losing your hearing is difficult to come to terms with and depression is common.  But by facing the problem and choosing to wear hearing aids you are taking control of your situation. Feeling in control and taking positive action can help to stave off the negative emotions which can lead to depression and social withdrawal.

Hearing aids can help prevent cognitive overload. If you can’t hear well you are having to concentrate more on conversations, you become hyper vigilant when crossing roads and you are in a constant state of high alert in case something happens which needs your attention.  By wearing hearing aids you don’t need to be on high alert or concentrate so hard to understand what’s going on around you.

Wearing hearing aids will keep the auditory area of the brain stimulated, keeping it healthy and less prone to tissue loss. Many people find hearing aids difficult to get used to at first. This is because the brain has started to get used to less sound. This is why many people who have hearing aids don’t wear them. They make things too noisy. The sooner mild hearing loss is treated, the easier it will be for your brain to adjust to the noise level.