Hearing aids may lessen dementia risk, new study finds

Dementia affects an estimated 6.7 million people in the U.S., according to a 2023 report published by the Alzheimer’s Association. Doctors and scientists have spent years researching the disease’s origins and ways to slow its progress.

Back in 2019, Johns Hopkins launched a study to examine the link between dementia and hearing loss, a connection doctors have noticed in many of their patients who suffer from both conditions, and whether hearing aids could help these patients slow the cognitive decline. This randomized study involved more than 3,000 people, who were either assigned to a control group that received counseling in chronic disease prevention, or a group that received hearing aids and treatment from an audiologist. They studied the groups every six months, then gave them a neuro-cognitive test at the end of three years.

The results of this study, published this week in The Lancet medical journal, show a possible link between using hearing aids and reducing cognitive decline for patients with the highest risk for it. Overall, the researchers didn’t find a difference for the group that received the hearing intervention as a whole. However, in the oldest subgroup, which had lower baseline cognitive scores and was at the highest risk, hearing aids slowed the rate of cognitive deterioration by 48%.

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But how are dementia and hearing loss connected?

During an interview with CNN, Dr. Frank Lin, the study’s primary author and a professor at Johns Hopkins University School of Medicine and the Bloomberg School of Public Health, discussed hearing loss’s possible physical and mental impacts on the brain.

First, he said that when someone has difficulty hearing, the brain must work harder and may have to to redistribute its “power” to understand what is being said. This overcompensation may lead to a diminished overall ability to function well. Lin said more study needs to be done on the possible physical impact of hearing loss on the brain, including possible decay and shrinking.

However, Lin also believes hearing loss often leads to isolation as patients avoid socializing, which causes complications for people at risk of dementia.

“For many, many years now, we’ve understood that social isolation and loneliness likely directly affects our risk of cognitive decline dementia, mainly through loss of cognitively stimulating activities but also just a loss of engagement with the world around us as we become … more pigeonholed at home sometimes,” Lin told NPR in an August 2022 interview.

With over-the-counter hearing aids available in the U.S. since October 2022 and hopefully more studies on the way, Lin and other scientific peers hope easier access to devices and more studies will open a clear path to helping people at high risk for dementia to slow the progression of the disease.