Hearing aids, counselling may slow cognitive decline for some seniors, new study finds

Seniors at risk of dementia who were given hearing aids and counselling had less cognitive decline over a three-year period, a randomized trial finds.

Research published Monday in The Lancet medical journal found that at-risk seniors saw their rate of cognitive decline nearly cut in half over three years if they wore hearing aids, compared to seniors who just received education. 

While past research has shown a link between hearing loss and cognitive decline, experts say this study supports the need for seniors to use devices to mitigate the risk.

In Canada, audiologists estimate that around three million people have some degree of hearing loss that could be improved with hearing aids, yet 80 per cent don't wear them.

"It's a testament that hearing intervention, it's not just improving your hearing; there are a lot of cascading effects that we see now," said the study's co-principal investigator Dr. Frank Lin. 

Lin, a professor at Johns Hopkins University's School of Medicine and Bloomberg School of Public Health, says the study shows that good hearing "decreases loneliness, improves your social engagement, you become more active [and] it might take a load off your brain." 

The randomized control trial involved 977 participants, who were about 77 years old on average. 

Some people were considered healthy, while others had underlying conditions like high blood pressure and diabetes, which put them at a greater risk for cognitive decline. 

Participants were randomly divided into two groups: one that got hearing aids with additional counselling and another that only took part in a successful aging health education class. 

Over three years, researchers measured the level of cognitive decline between the two groups. 

There was no significant difference in cognition between the two groups overall, nor was there a notable difference for the healthy participants across both groups.

But when researchers looked at the results for just the participants who were at higher risk of dementia, those who got hearing aids slowed their cognitive decline by 48 per cent over the study period.

According to Lin, researchers suspect that there are three major ways hearing loss can impact the brain. 

The first, he said, is related to cognitive load, which means that there's excessive work being done by the brain to compensate for poor hearing.