Hearing loss and dementia can often occur together as we get older and have an impact on each other. We know they are linked in several ways, but we don’t know exactly how. We’re funding vital research to find out more.
Hearing loss as a risk factor for dementia
There is strong evidence to show that:
- hearing is an essential part of brain health
- mild hearing loss doubles the risk of developing dementia
- moderate hearing loss leads to three times the risk
- severe hearing loss increases the risk five times.
But can steps be taken to reduce or avoid this risk? An international review in medical journal The Lancet, published in 2020, suggested that hearing loss is one of twelve key risk factors for dementia that are possibly modifiable (factors that can be changed to reduce dementia risk).
The review suggested that one in three cases of dementia could be prevented if more people looked after their health throughout their lives. Other key risk factors for dementia include social isolation, smoking and depression.
Unaddressed hearing loss in mid-life was predicted to be the highest potentially modifiable risk factor for developing dementia. This is hugely important. Can addressing hearing loss – for example, by using hearing aids – reduce this risk? It’s vital we find out.
It’s also vital that we better understand the link between hearing loss and dementia – it will lead to improved diagnosis and new effective treatments for both conditions.
Misdiagnosis and further links
Hearing loss can sometimes be misdiagnosed as dementia. People with dementia can have difficulty communicating with others, including finding the right words, or signs, for what they want to say. They may have difficulty processing what they’ve heard, particularly if there are distractions. According to some researchers, this difficulty in processing information (when there is competing information) can be one of the first signs of cognitive impairment.
We also know that hearing loss can speed up the onset of dementia, or make the symptoms of dementia appear worse, and dementia can heighten the impact of hearing loss.
Hearing health and reducing risk
Evidence suggests that managing hearing loss could reduce or delay the impact of dementia. It’s therefore important to check our hearing regularly. Over 40% of people over 50 have hearing loss, so checking our hearing in mid-life is especially important.
Once hearing loss is diagnosed, it can be managed with hearing aids. Hearing aids can significantly increase people’s ability to take part in everyday life and communicate with friends and family, improving people’s wellbeing. This potentially reduces the risk of depression and social isolation and slows cognitive decline.
Research is starting to suggest that hearing aids might slow cognitive decline for people who are at high risk of dementia (such as people with cardiovascular disease). More research is needed to show whether they can slow cognitive decline in everyone with age-related hearing loss.
Hearing aids are available on the NHS and privately.
To investigate the links between hearing loss and dementia more closely and help find the answers that so many people are desperate for, we’ve been working with Alzheimer’s Research UK since 2018 to fund research into this important issue. Together, we’ve so far invested more than £850,000 into this area of research, with more planned in the future.
Read more about the researchers and projects we’re supporting.
Dr Nicolas Michalski is studying whether hearing loss causes changes in the blood supply to the brain and in turn, whether this could lead to dementia. He’s also investigating whether treating hearing loss can prevent these changes and, if so, prevent the development of dementia.
So far, they have found that hearing loss causes hearing regions of the brain to have a less robust blood supply. They are investigating whether age-related hearing loss could therefore trigger a cascade of changes to the brain’s blood supply that ultimately leads to dementia. They will also investigate whether treating hearing loss can reverse these changes and potentially help to prevent dementia.
Professor Jason Warren is studying changes in the brain that occur during hearing loss and dementia, and how they might be linked. He’s investigating if changes to hearing can act as an early warning signal for dementia. This would allow people to receive treatment and intervention earlier, lessening the impact of both conditions.
In her project, Professor Sally Dawson is using data from the largest existing genetic studies for which there is information on both hearing ability and dementia status to look for evidence of common inherited causes that might underlie both hearing loss and dementia. She’s also using other medical data from these studies to understand if other factors, such as cardiovascular health, might also play a role.
Her work so far has shown no genetic evidence to support the idea that hearing loss causes dementia (or vice versa), or that there is a shared underlying cause.
However, it does suggest that there may be common processes underlying both conditions linked to signalling chemicals used to send messages in the brain. She has also found evidence to support the idea that there is a more complex link between hearing loss, dementia and other conditions such as diabetes and cardiovascular disease.
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For information, support or advice about dementia, call the National Dementia Helpline on 0300 222 11 22.
To find out more about hearing loss and tinnitus, see our ear health information or contact us. You can also check your hearing with our free hearing check.