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A large clinical trial found that hearing aids slowed cognitive decline by 48% among subjects with a higher risk of dementia. Maica/Getty Images
  • The largest clinical trial to date investigated the impact that hearing aids had on reducing cognitive decline.
  • Researchers found a 48% reduction in risk among participants at a higher risk of developing dementia.
  • The results add to a growing body of research studying the link between hearing loss and cognitive decline.

The National Institute on Aging reports that every three seconds, someone in the world develops dementia — a collection of diseases affecting the brain, causing cognitive decline and memory loss.

The most common type of dementia is Alzheimer’s disease(AD).

There are various reasons a person may get dementia, and there are also a number of risk factors for dementia. One of those is hearing loss.

Previous studies have correlated hearing loss with increased dementia risk.

Now, researchers from the Aging and Cognitive Health Evaluation in Elders (ACHIEVE) study reported their findings from the largest clinical trial to investigate whether a hearing loss treatment intervention can reduce a person’s risk for cognitive decline.

Scientists found participants in a higher-risk subgroup slowed cognitive decline by 48% when using a hearing aid and receiving assistance and counseling from an audiologist.

This study was recently published in The Lancet.

The ACHIEVE study is a randomized trial of participants ages 70 to 84 with untreated mild to moderate hearing loss and no substantial cognitive impairment. The study was conducted at four sites in the U.S.

A total of 977 people were recruited for the study. About 740 of them were healthy community volunteers newly recruited to the study. About 240 were participants in the Atherosclerosis Risk in Communities (ARIC) study.

According to researchers, participants in the ARIC group had more risk factors for cognitive decline, lower baseline cognitive scores, and a faster rate of three-year cognitive decline during the study than the others.

One portion of participants received a three-year intervention that included hearing aids, a hearing “toolkit” to help them with self-management, and ongoing instruction and counseling with an audiologist.

The control group only received speaking sessions with a health educator to discuss chronic disease prevention.

At the end of the three years, researchers found participants from the ARIC study who received hearing aids and intervention slowed their cognitive decline rate by 48%.

“A 48% reduction in cognitive decline is sizable, and we were thrilled to see that the benefit was so large,” Dr. Frank Lin, professor at Johns Hopkins University School of Medicine and the Bloomberg School of Public Health and co-principal investigator of the ACHIEVE study, told Medical News Today.

According to Dr. Lin, researchers have known for over a decade that hearing loss is strongly linked with a risk of dementia and cognitive decline.

“However, we didn’t know if treating hearing loss could in fact reduce cognitive decline and potentially even lower the risk of dementia,” he added.

Dr. Lin explained three main mechanisms that offer insight as to why hearing loss may be associated with dementia:

“First, with hearing loss, speech, and sound are garbled by the time they reach the brain, which requires the brain to use extra effort for processing the signals that come from the ear. The brain then has fewer resources for supporting thinking and memory abilities.

Second, with hearing loss, the parts of the brain that are stimulated by speech and sound are now under-stimulated, which can lead to atrophy and changes in brain structure and function.

Third, hearing loss can make communicating with others more difficult, which can lead to social isolation, another risk factor for dementia.”

— Dr. Frank Lin, co-principal investigator of the ACHIEVE study

This is not the first study to examine a link between hearing loss, hearing aids, and dementia.

A 2022 study found the use of hearing aids might help reduce cognitive decline associated with hearing loss.

After reviewing this research, Dr. Courtney Voelker, a board certified neurotologist and director of the Adult & Pediatric Cochlear Implant Program at Pacific Neuroscience Institute at Providence Saint John’s Health Center in Santa Monica, CA, told MNT this is an exciting study that is another piece of evidence to show that not only is hearing loss linked to cognitive decline as we go through the aging process, but we can actually do something about it.

“There’s building evidence, including this paper, that when we aggressively treat hearing loss — both with hearing aids or cochlear implants, depending on the severity of the hearing loss — we can actually improve cognition,” she continued. “And this is very exciting.”

Dr. Voelker said she counsels her patients when talking about cognitive decline about the importance of keeping brain neurons stimulated and activated.

“And it’s very interesting — patients really respond to this,” she continued. “People that initially may not have wanted to wear hearing aids really do take the cognitive dementia element seriously when making their decision. I also tell patients we would never let people walk around with vision loss without glasses, and so why do we let people walk around with sort of foggy hearing without hearing aids? And that analogy seems to resonate with patients as well. We want our hearing to be as crisp and clear as our vision is with glasses.”

— Dr. Courtney Voelker, neurotologist

And MNT also spoke with Dr. Raphael Wald, a neuropsychologist with Marcus Neuroscience Institute, part of Baptist Health, at Bethesda Hospital East.

He agreed clinicians have known for some time that there is a link between hearing loss and cognitive decline, and the results of this study provide another approach to looking at this link.

“This research bolsters the ability of doctors to talk to their patients about compliance with hearing aids,” he continued.

“I often find myself talking to my patients about the fact that untreated hearing loss is a risk factor for accelerated cognitive decline in the hope that they will go along with treatment.”

“In the future, it would be helpful for researchers to look at the reasons that many patients are noncompliant with hearing aids,” he added. “This would allow us to try to find solutions to their concerns.”

At the conclusion of the study, researchers also reported in both the ARIC group and community volunteers group, the hearing intervention improved study participants’ communication skills, social functioning, and feelings of loneliness.

“We know from previous research that loneliness and social isolation have a detrimental effect on people’s health as they age,” Dr. Lin said.

“While we don’t know the exact mechanism through which loneliness may increase dementia risk, there are plenty of clues, and multiple factors may be involved.”

“Individuals who are isolated tend to be less active, more often depressed, and less likely to adhere to medical treatments — all of which could potentiate the risk of dementia over time,” he added.

According to the World Health Organization (WHO), about 20% of the world’s population lives with some type of hearing loss.

A person can lose their hearing for a variety of reasons, including:

Additionally, hearing loss is more common as we age with the greatest amount of hearing loss usually occurring over the age of 60.

Depending on the situation, hearing loss can be temporary or permanent. Age-related hearing loss is permanent — there is currently no cure, and it may worsen over time.

Treatments for hearing loss

When treating age-related hearing loss, there are a few options including:

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