In recent years, there has been a huge surge of interest in the link between our hearing and our chances of getting dementia.
Stories in the press have suggested that up to a third of dementia cases may be caused by hearing problems.
TV doctors are telling viewers that having a hearing test can help prevent the syndrome, while adverts for hearing aids are claiming the devices can slow cognitive decline.
But, as so often is the case, the relationship between our hearing and our brain health is complex.
And while there are clear benefits to treating hearing loss, the evidence that hearing aids can prevent dementia isn’t quite what it seems.
Finding a connection
Studies linking the decline or loss of senses to poorer cognitive ability date back to the 1990s, when a research project known as the Berlin Aging Study first found an association between declines in hearing or vision and declining brain or cognitive function.
But recent interest in the link between hearing and dementia can be traced back to a major report called ‘Dementia Prevention, Intervention and Care’, published in The Lancet in 2017.
The widely-read report declared for the first time that hearing loss was the biggest ‘modifiable risk factor’ for dementia. In other words, something that contributes to our chances of getting the disease that we can do something about (unlike our genetics or family history).
The report suggested that hearing loss might play a bigger role in dementia than poor diet, lack of exercise, poverty or social isolation – and that treating it could prevent as many as eight per cent of dementia cases worldwide.
Although the report acknowledged that the exact nature of the link was unclear, the idea that hearing loss actually causes dementia has since become hard-baked into public discussions of both health problems.
With the number of cases of dementia predicted to triple by 2050, members of the public and health professionals alike are desperate to find ways to reduce the prevalence of this harrowing cognitive condition – and hearing looks like it could be one of the easier risk factors to fix.
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A common problem
The trouble is, it hasn’t actually been proven that hearing loss causes dementia, or how one might lead to the other.
As many as two-thirds of people over 65 will experience hearing loss, meaning a huge proportion of people with dementia will have had hearing loss first.
This large statistical association means studies like ‘Dementia Prevention, Intervention and Care’ rank it as a major risk factor, even though it might not necessarily be an important factor to any one person.
“Because hearing loss is so common, it appears to be the biggest risk factor,” says Dr Jenna Littlejohn, a research associate at the University of Manchester specialising in dementia and hearing loss.
“But that doesn’t mean it’s the main or most likely cause to you as an individual. It’s misleading to people who don’t know much about statistics or epidemiology.”
Hearing involves a complex sensory pathway that starts with the delicate structures of the outer and middle ear, continues into the sensitive organs of the inner ear, and then into the neural network that takes sound to the brain and deciphers what’s heard.
Age-related hearing loss, known as presbycusis, is often caused by the slow breakdown of the fine hair cells that help convert vibrations of air in the middle ear into electrical signals, but can also be caused by the decline of function in any other part of the hearing pathway.
There are several theories as to how hearing loss might contribute to cognitive decline and dementia.
The first, and most intuitive, is that not being able to hear properly causes people to avoid conversations and withdraw from social life, increasing their risk of depression and reducing the amount and variety of stimulation their brain receives.
These factors – depression and low stimulation levels – are both known to increase the risk of dementia.
Another theory is that when a person has poor hearing, their brain has to do far more work to figure out what’s being said – increasing the brain’s ‘cognitive load’.
Listening, especially following speech, becomes an effortful and stressful process, which reduces the amount of resources the brain has for other processes, such as memory or reasoning.
It’s no surprise, then, that this results in worse scores on cognitive tests.
Others think there could be a more direct physiological link. For example, some studies have shown that age-related hearing loss results in a decrease in overall brain volume, or an increase in the rate that the brain shrinks with age.
The ‘use it or lose it’ theory of development suggests that a lack of stimulation may cause the sound and language processing centres of the brain to wither. The knock-on effects on other parts of the brain then compound normal cognitive decline.
Which came first?
But there are other possible explanations for the numerous studies that have shown that people with untreated hearing loss can be between two and five times more likely to get dementia, depending on the severity of the deafness.
One is the possibility that many people with hearing loss may have already had very early-stage, undiagnosed dementia, before being diagnosed many years later.
“The physiological changes in the brain that cause dementia can appear up to 20 years before a person gets a diagnosis, so in a study, it’s hard to say for sure that a person’s hearing loss truly preceded their dementia,” says Littlejohn.
“It could even be that early, undiagnosed dementia is actually causing the hearing loss – what we would call reverse causation.”
Given that some of the early signs of hearing loss and cognitive problems are similar, people with hearing loss may also be more likely to be diagnosed as having some degree of cognitive decline.
For example, if someone is having trouble keeping up with conversations or repeats things that have already been discussed, it could be caused by problems with their memory, but it could also be because they didn’t hear it properly in the first place.
Even if studies are able to prove conclusively that more people get hearing loss first and then go on to get dementia later, there could be an unknown factor that’s causing both.
This issue might be, for example, a disorder that affects both the neurons of the ear and the brain, but becomes apparent in the ear first because it’s so delicate and has a single, easily measurable function.
It’s for these reasons that Littlejohn is sceptical that hearing aids could ever be used to prevent dementia on a grand scale: by amplifying sound, they only treat the symptoms, not the cause, of hearing loss.
“If it’s found to be the case that there’s a physiological reason that hearing loss leads to dementia, hearing aids don’t treat that underlying physiology,” she says.
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Help from hearing aids
Plus, the research from clinical trials is simply not that strong. The most commonly cited evidence that hearing aids can prevent dementia is a study known as the Aging and Cognitive Health Evaluation in Elders (ACHIEVE) trial.
It followed almost 1,000 people in the US aged 70–84 for three years, comparing whether those who received regular hearing assessments had less severe levels of cognitive decline.
The findings that many researchers have focused on is that a small subset of people, marked as already having a high risk of dementia, appeared to have reduced levels of cognitive decline after receiving hearing aids.
However, the main findings of the trial were actually negative: there was no evidence that using hearing aids reduced cognitive decline in the much larger, healthier group of people studied.
“For every study that’s found that people do better with hearing aids, there are others that found there’s no difference, or they do worse,” says Littlejohn.
Interestingly, the most recent update of The Lancet’s ‘Dementia Prevention, Intervention and Care’ report, published in 2024, revised the relative role of hearing loss in dementia down, while those of other factors such as depression and diabetes have risen.
The World Health Organization still doesn’t publicise hearing loss as a major modifiable risk factor at all.
Instead, being physically active, not smoking, maintaining a healthy diet and avoiding harmful use of alcohol are all considered more important factors in reducing your chances of getting dementia.
Still, being able to hear properly remains an important part of staying healthy. Our hearing has a proven link to our quality of life, and hearing aids undoubtedly help keep us active, engaged, independent and therefore healthier as we age.
Kevin Munro, a professor of audiology at the University of Manchester, is trying to change the narrative about why people should get regular hearing tests.
“Dementia frightens the life out of people, and reports like ‘Dementia Prevention, Intervention and Care’ want to paint a positive picture, to say that there are things that can be done,” he says.
“But we have to be careful about how we explain this to members of the public. I get calls all the time now from people completely worried, saying ‘I’ve seen a poster saying untreated hearing loss causes dementia’, and ‘my doctor never told me this’… I’m spending a lot of time trying to undo this misinformation.”
Munro is concerned that people might be frightened into buying hearing aids or avoid hearing tests if they believe it will reveal dementia – or that health professionals will focus on hearing at the expense of other important risk factors.
He’s now working with audiologists and hearing aid providers to help them communicate the complexities of this link more carefully.
Meanwhile, researchers like Littlejohn are designing more sophisticated studies to get a clearer understanding of how different types of hearing loss contribute to the many different types of cognitive decline and dementia people might get.
Others are looking at how loss of sight seems to have a very similar effect on dementia risk as a loss of hearing.
And a study published in June 2025 has suggested that sleep disorders might exacerbate hearing loss – with all of the same caveats above applying to this new, complex and understudied link.
The message Munro wants to get out there is clear: getting your ears tested, and any hearing problems sorted, will only benefit your happiness and health. But don’t bank on it as an easy way to save you from dementia in the future.
Risk management
Your age and genetics are the biggest risk factors when it comes to dementia and, unfortunately, you can’t do much about either of them. You can do something about your so-called ‘modifiable’ risk factors, however.
To be clear, these risk factors don’t necessarily cause dementia – they’re just strongly correlated with the disease.
Generally, people in good physical and mental health are more able to withstand the slow, underlying damage that causes the symptoms of dementia.
Below you can find the top five (based on relative risk – the likelihood of developing a disease in an exposed group compared to an unexposed group) modifiable risk factors for dementia, all of which are ranked as higher relative risk factors for dementia than hearing loss:
Depression
Like other risk factors, the link between depression and dementia is complex. Depression might cause lifestyle changes that worsen dementia risk (like substance abuse or social isolation), or there might be a more direct cause.
People may also be more likely to be depressed when in the early stages of cognitive decline.
Traumatic head injury
There’s good evidence that a major injury to the brain increases the risk of dementia later in life. Many neurologists say that wearing a helmet when cycling is one of the best things a person can do for their brain health.
Diabetes
Diabetes is one of a cluster of risk factors related to cardiovascular health that increase dementia risk.
Poor diet, high cholesterol, obesity, heart disease, infrequent exercise, diabetes and stroke are very closely linked to one another and all raise the risk of dementia.
Less education
It’s unclear why people with higher quality education, and higher educational attainment, have a reduced dementia risk.
It may be that they go on to do more mentally stimulating jobs and activities, which has a protective effect on the brain, or it may be linked to poverty/lifestyle in those with low education levels.
Infrequent social contact
Another risk factor where the nature of the link is unclear.
Does infrequent social contact cause depression, which then increases dementia risk, or does it more directly cause dementia through a lack of mental stimulation? Or is the link due to people socialising less when their brain starts to decline?
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