Health
How looking after your hearing could help stave off dementia
Dementia is currently the leading cause of death in England and Wales, with 1 in 11 adults over 65 diagnosed with the disease. New drugs are constantly being developed to help slow symptom progression, but with variable success. The most recent, Lacanemab, was rejected by the UK health regulator NICE after being deemed too costly for the small benefits it offers.
In the meantime, experts are investigating approaches that may help reduce our chances of developing dementia in the first place.
The scientific journal The Lancet recently updated its ongoing report on dementia prevention. It highlighted 14 modifiable risk factors that – if addressed – could prevent or delay dementia onset. Factors including hypertension, traumatic brain injury, and smoking all made the list. However, the joint highest risk factor (tied with high LDL cholesterol levels) is a concern experienced by many in later life: hearing loss.
The association between hearing loss and dementia
You’d be forgiven for feeling confused as to how hearing ability and dementia onset are linked. Even the experts still aren’t entirely sure about the roots of the association.
“There are various hypotheses, all of which are plausible,” says Professor Tom Dening, professor of dementia research at the University of Nottingham. However, there are three theories that scientists believe to be particularly credible.
Brain changes and degeneration
The first is that hearing loss and dementia are a two-way street. “You may have some neurodegenerative process, like Alzheimer’s disease, going on in the background, and this causes dementia. But it may also affect how you process what you hear,” says Tom.
Multiple studies have noted changes in brain structure and neural pathways among individuals with hearing loss, many of which are also linked to dementia. For instance, Chinese researchers found that those with hearing impairment had lower gray matter and hippocampus volume in their brains – two markers of dementia. Meanwhile, an Australian study found that individuals with Alzheimer’s disease had notable changes in their auditory system, such as degeneration and plaques.
The reciprocal nature of dementia and hearing loss means one is sometimes mistaken for the other.
“It may be that hearing loss or difficulty understanding speech is simply an early sign of dementia,” explains Tom. “But it’s misinterpreted as being an ear problem, when it’s more of a brain problem.”
Social isolation
The second relates to social isolation. When you can’t hear as well as you once did, it’s harder to follow conversations, meaning you feel like you’re missing out and you’re less mentally stimulated.
“Social isolation is a risk factor for dementia because people become disconnected from the rest of the world and relationships,” says Fran Vandelli, dementia lead at Bupa Care Services. “Without adequate stimulation, your brain becomes more vulnerable to rapid deterioration.”
A study of mice found that experiencing reduced auditory signals and stimulation resulting from an impaired cochlea (a crucial part of the inner ear) can lead to alterations in brain neuropathy.
However, the issue of social isolation links hearing loss with another of the 14 modifiable risk factors – depression. “Some of the symptoms of depression are the same as the symptoms of dementia, so it can be difficult to tell them apart,” states Fran. “And symptoms of depression will exacerbate any existing symptoms of dementia.”
Cognitive load
The final main hypothesis relates to cognitive load. This is when the brain has to put more energy into hearing and processing sounds. This means other important cognitive functions are neglected.
“Some studies suggest that the extra burden involved in interpreting auditory information can cause changes in the brain,” adds Caroline Scates, deputy director for Admiral Nurse Development at Dementia UK. “Especially if there’s lots of background noise or music, then your brain is working harder to hear sounds coming in; and that can have an effect on cognitive decline.”
Various studies have linked excessive cognitive load from hearing loss to changes in brain structure and neurodegeneration.
Understanding your risk
If you experience hearing loss, don’t panic.
“Hearing loss is one of the risk factors for dementia, but it doesn’t mean that all people who experience hearing loss will go on to develop dementia,” assures Fran. “Current evidence doesn’t confirm that hearing loss is a definite cause of dementia, but it highlights risks that shouldn’t be ignored.”
Caroline agrees. “It’s the same with all of those 14 modifiable risk factors. Just because you drink or are obese, it doesn’t mean you’ll get dementia,” she says. “All we’re trying to do is raise awareness of things people can do to reduce that risk.”
So what level of hearing loss is potentially linked to dementia?
“Any level of hearing loss can have a long-term detrimental effect on cognitive function,” says Elizabeth Newbould, audiology development lead at Leightons Opticians & Hearing Care. “However, the greater the level of hearing loss, the higher the risk factor of developing cognitive issues.”
One study, for instance, found that dementia prevalence among participants with moderate to severe hearing loss was 61% higher than among those with normal hearing levels.
It’s crucial to understand that, in The Lancet report, hearing loss is noted as contributing just a 7% dementia risk. “Only about 40% of the total risk of dementia is associated with these 14 factors,” states Tom. “The biggest risk factor for dementia is our age. The older you get, you’re far more likely to develop it. And the genetic contribution is [also] quite large.”
Maintaining good hearing
While the jury is still out on the level of impact hearing loss has on dementia, looking after your ears and treating any hearing loss as soon as possible is a good idea for multiple reasons. Elizabeth says doing so helps to keep the brain stimulated. It also minimises the risk of cognitive decline and assists you in enjoying everyday life to the fullest.
There are various steps you can take to help keep your ears as healthy as possible, reveals Laura Monaghan, an audiologist from the Professional Advancement Team at Specsavers Audiology. These include:
- Wear appropriate hearing protection when in noisy environments or exposed to loud sounds
- Avoid pushing anything (such as cotton buds) into your ears – although earphones, hearing protection, or hearing aids are OK
- Have A GP check ‘unusual’ ear symptoms early. This includes pain, discharge, dizziness, tinnitus, unequal or distorted hearing, and abnormal facial sensations
- Reduce your risk of ear infections by not sharing earphones or hearing protection with others. Wearing swim plugs or similar when swimming can help, too
- Don’t try to remove wax build-up or blockages yourself; have this done by a professional
- Look after your general health
- Get your hearing checked
To aid, or not to aid?
If you’re experiencing hearing loss, wearing a hearing aid can make a significant difference. What’s more, the noticeable lumps of plastic hanging on the outside of the ear are a thing of the past.
“Hearing aids these days are small, discrete, and packed with technology and programming to help make hard-to-hear sounds a part of your world again,” shares Laura.
Tom says the big question is whether wearing a hearing aid (at an early enough stage) will affect a person’s risk and incidence of dementia. “That’s quite a hard question to investigate, although there is some evidence,” he explains.
For example, one study of older adults at a high risk of dementia found that wearing hearing aids lowered the rate of cognitive decline by almost 50% over a three-year period. Other research noted that dementia prevalence was 32% lower among participants with moderate to severe hearing loss who used aids, compared to those with hearing loss who did not wear aids.
But this doesn’t mean that wearing a hearing aid will ensure you stay dementia-free. As highlighted, hearing loss is just one of many contributors to the disease.
“Once you do these things, you’ve got to be realistic that things aren’t guaranteed; they’re not miracle cures,” states Tom. “But they may provide significant benefits now. These are just as important as worrying about developing dementia in the future, I think.”
If you’re concerned about hearing loss or impairment, many opticians now offer free hearing tests. If you need advice or support on living with dementia, contact Dementia UK’s Admiral Nurse Dementia Helpline on 0800 888 6678 or email [email protected].
Words: Chantelle Pattemore
