About 65% of the factors that cause dementia, such as genetic make-up, cannot be modified. However, 35% are modifiable.
That’s the question Grant Searchfield, director of the University of Auckland’s hearing and tinnitus clinic, and Megan McAuliffe, from the University of Canterbury’s department of communication disorders, hope to answer in a $1.15 million study involving 200 people aged 65-plus.
All 200 will be first-time hearing-aid users who have been tested and found to have minor difficulties with memory and understanding, which can be an early sign of dementia. Half will be fitted with hearing aids tuned in the normal way; the others will get “cogniaids” – normal hearing aids that have been tuned to take into account the user’s processing difficulties.
“Many of the features in modern hearing aids are designed to work for people who are able to use quickly changing information,” says Searchfield. “A hearing aid tuned this way can create distortion that is not helpful to a person with slower processing – the information essentially becomes jumbled and unclear.”
He says cogniaids will be tuned to make sure the user hears only the most important sounds.
At this stage, the researchers are still looking for participants. But Searchfield says if the study shows that cogniaids help slow cognitive decline, audiologists here and overseas could start making similar adjustments when they fit hearing aids in older people having trouble processing information.
“Our goal would be to roll it out in New Zealand and to make sure New Zealand audiologists are providing best practice for older people,” says Searchfield. “The results of a study of this size will also make an impact internationally.”
Researchers have known for a long time that untreated hearing loss can speed up the age-related decline in our ability to process and understand information. Searchfield says there are several reasons for this. The first is that the lack of auditory input means the brain gets less of a workout, which can affect how well it functions. The second is the loss of stimulation caused by social isolation.
“When you have hearing loss, you’re less likely to be involved in conversations or engage with people, and that also means the brain isn’t getting exercised.”
It’s possible, too, that the brain changes that lead to dementia can cause hearing loss. The greater the hearing loss, the greater the risk of dementia.
“It appears that people with mild hearing loss have two times the risk of developing dementia, and those with severe hearing loss have five times the risk.”
Younger people with hearing loss are not affected in the same way, possibly because their brains are more able to accommodate the change.
Searchfield says it’s important to note that untreated hearing loss in older age will not inevitably lead to dementia, but it is a modifiable risk factor.
About 65% of the factors that cause dementia, such as genetic make-up, cannot be modified. However, 35% are modifiable. They include lifestyle changes such as giving up smoking and preventing or treating diabetes. “The No 1 modifiable factor is, surprisingly, hearing.”
He says research has already shown that wearing hearing aids tuned in the normal way can help stave off cognitive decline, although they must be worn regularly and used properly.
“Simply buying a hearing aid is not going to help. Being able to use it comfortably and being a good wearer is the recipe to achieving the benefits.”
His study is intended to find out whether it’s possible to increase those benefits with a few simple tweaks. “Can the benefits of using a hearing aid be optimised even more? That’s what we’re trying to find out.”
However, he admits one possible obstacle to the widespread use of cogniaids may be that many older people are reluctant to get hearing aids of any kind. Even in countries that provide free hearing aids, such as the UK, only about 40% of those who need them actually get them.
“Cost is part of the problem, but so is the image of hearing aids. Many people don’t really believe they are going to help.”
This article was first published in the July 14, 2018 issue of the New Zealand Listener.