As we age, the frightful prospect of dementia is, in some respects, out of our hands. Simply getting older is the biggest risk factor, followed by genetics.
There are factors we can address, like diet, lifestyle and managing blood pressure, cholesterol and diabetes.
But a study published earlier this month in the journal JAMA Neurology looked at hearing loss, which is found in about two-thirds of adults over 70.
The analysis of 31 other studies concludes that, for people with hearing loss, hearing aids reduce their risk of long-term cognitive decline by 19%.
Dr. Justin Golub, an otologist at Columbia University who was not part of the study, said the big question is: Do hearing aids prevent dementia? Do they improve cognition?
"And with this study that just came out, I think we can say, 'Probably,' " he said. "But to really say that that's the case, what we need is a randomized controlled trial, and so that's the next step. And, luckily some of these are coming down the turnpike.
A modifiable risk factor
Jennifer Deal, a researcher at Johns Hopkins University, said there should be a few caveats because this study relies heavily on observational research.
She is working with Dr. Frank Lin, director of the Cochlear Center for Hearing at Johns Hopkins, and others on a randomized trial of nearly 1,000 older seniors with hearing loss. It aims to nail down whether hearing aids reduce the risk of dementia.
Deal points to research showing that it's the biggest modifiable risk factor.
"If hearing loss does cause dementia," she said, "then that means we can potentially prevent up to 8 percent of dementia cases."
This is why the randomized trial Deal is working on is so important.
Researchers say there are three theories that could explain the connection between hearing loss and dementia.
The first is reduced socialization.
"People who have hearing loss, they tend not to listen to interesting radio programs like this," Golub said in an interview for WMFE. "They tend not to go out and socialize as much. And they're not having as much cognitively stimulating conversation. And over time that might not be good for your cognition."
The second explanation is increased cognitive load. Because of changes within the ear, the brain is getting a garbled signal that takes more effort to process, effort that should be spent forming a memory or understanding meaning.
Finally, the experts say parts of the brain associated with sound, speech and memory formation actually shrink in people with hearing loss.
OTC hearing aids
Executive director Barbara Kelley of the Hearing Loss Association of America said lack of access to care and high prices have kept many seniors from getting the help they need. That’s changing since October, when over-the-counter hearing aids became available.
There is a stigma, as well. People associate hearing aids with old age. But for a generation of baby boomers, they can be key to staying vibrant and healthy.
"Baby boomers really are the ones who want to stay fit and they want to stay active," Kelley said. "Hearing loss and hearing health is definitely part of that."
Golub foresees a snowball effect from over-the-counter hearing aids. They'll become automatic, like eyeglasses or seat belts.
"For whatever reason," he said, "we haven't got into the habit of sticking hearing aids in our ears when we have hearing loss. And it just makes sense to do that. And I think over the next decade or so we're going to see a lot of change in that regard."
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