The Role of Hearing Aids
However, the jury is out on the role of hearing aids in preventing dementia.
A large observational study published in 2023 in Lancet Public Health was hailed by its investigators as providing “the best evidence to date” that hearing aids could mitigate the impact of hearing loss on dementia (Lancet Public Health. 2023 May;8[5]:e329-e338. doi: 10.1016/S2468-2667[23]00048-8). However, the authors voluntarily retracted the paper in December 2023 due to a coding error.
Despite this, a large meta-analysis published in JAMA Neurology suggested that hearing aids might reduce cognitive decline and dementia risk and even enhance short-term cognitive function.
Additionally, the ACHIEVE study, the first randomized trial to investigate these issues, included nearly 1000 older participants from two populations — those from the ARIC study and healthy volunteers. Participants were randomly assigned to receive either a hearing intervention or education on healthy aging.
Although the primary endpoint of change in standardized neurocognitive scores at year 3 showed no significant difference between the hearing intervention and health education groups, the ARIC cohort experienced a notable 48% reduction in cognitive decline with hearing aids compared with education.
Dr. Lin explained that, due to the study’s design, the control group was healthier than the ARIC cohort, which was at higher risk for cognitive decline due to factors such as age and diabetes. This is where they observed a strong effect of hearing intervention in reducing cognitive decline within just 3 years, Dr. Lin said.
Conversely, the hearing aids had minimal impact on the healthy controls, likely because they had not experienced cognitive decline to begin with. Essentially, the benefits of hearing aids were more apparent once cognitive issues were already present.
“It seems sort of obvious. In a group of people who aren’t at risk for cognitive decline, a hearing intervention isn’t going to benefit their cognition” in the short term, Dr. Lin noted. That said, the investigators are continuing to follow the healthy controls to determine whether hearing aids lower dementia risk over the long term.
Which Comes First?
Some experts have questioned the directionality of the link between hearing aids and dementia — do hearing aids reduce dementia risk or are individuals with dementia simply less likely to use them?
Dr. Lin noted that observational studies often have confounders. For instance, people who use hearing aids are often healthier and better educated. This makes it difficult to distinguish the effect of the intervention from the factors that led people to use it, he said.
In contrast, the ACHIEVE trial, a randomized study, was designed to separate these factors from the hearing intervention, Dr. Lin explained.
However, he added that ACHIEVE was not specifically powered to assess dementia development, focusing instead on cognitive decline. The investigators plan long-term follow-up of participants to evaluate the impact on dementia in the future.
So, given the current evidence, what should clinicians tell their patients?
Because all people experience some degree of hearing changes as they age, which can gradually affect communication and social engagement, it’s important for everyone to be aware of their hearing health, Dr. Lin said.
He noted there are apps available that allow individuals to measure their hearing with their phones, including determining their “hearing number.”
With respect to hearing aids, Dr. Lin noted that if individuals have trouble participating in everyday activities, addressing hearing issues and considering a hearing intervention is crucial.
There’s no medical risk associated with hearing aids, he said. Even if they only improve social activities and engagement, that’s a benefit. If they also have potential positive effects on cognitive health, “even better,” he added.
Dr. Lin noted that as of 2022, hearing aids are now available over the counter, a move that has improved accessibility. In addition, new technologies, such as stylish “hearing aid glasses,” are being developed to offer more appealing options and reduce the stigma associated with traditional devices.
People often view hearing loss as a significant life event and are reluctant to admit they need hearing aids. However, focusing on “what’s your hearing?” as a neutral tracking metric could make it easier to adopt new technologies in the future, Lin said.