Study: Hearing Aid Rx Not Linked to Better Cognition, But Lower Dementia Risk

A new large-scale study published January 14 in Neurology, the journal of the American Academy of Neurology, examines whether receiving a hearing-aid prescription is linked to changes in memory and thinking over time—and whether it relates to dementia risk.

Some key takeaways in the study include:

• With self-reported moderate hearing loss, people who were prescribed hearing aids did not score higher, on average, on yearly cognitive tests than those who weren’t prescribed aids.
• Over 7 years, the group with hearing-aid prescriptions showed a lower rate of dementia (about 5% vs 8%), which worked out to roughly a 33% lower risk after researchers accounted for factors such as age, sex, and common health conditions. This finding does not prove hearing aids prevent dementia, but points to an association (i.e., not cause-and-effect).
• Participants who reported using their hearing aids more frequently tended to have a progressively lower dementia risk.

“Hearing loss is more common as we age and previous research has found it may increase the risk of memory and thinking problems, including dementia, but less is known about how treating hearing loss with hearing aids may impact brain health,” said study author Joanne Ryan, PhD, of Monash University in Melbourne, Australia, in a press statement. “Our study followed people with hearing loss, some of whom were prescribed hearing aids and some who were not, and found cognitive scores were similar for both groups. However, we also found that hearing aids were associated with a lower risk of dementia.”

Who was studied

Researchers followed 2,777 older adults in Australia (average age 75) who did not have dementia at the beginning of the study. All participants reported moderate hearing loss and had never used hearing aids previously.

During the follow-up period, 664 participants received a hearing-aid prescription. Those individuals also answered questions about how often they used their devices.

What the researchers measured

Participants were tracked for 7 years and completed annual cognitive testing, assessing areas such as memory, language, and processing speed. Over the course of the study, 117 people developed dementia.

What they found

When the researchers compared the prescription group with those who were not prescribed hearing aids, average cognitive test scores were essentially similar over time. In other words, being prescribed hearing aids did notcorrespond to higher overall performance on those tests.

However, the dementia outcome looked different. After adjusting for key factors (including age, sex, and conditions such as diabetes and heart disease), the researchers estimated that:

• The prescription group had about a 5% chance of developing dementia during the study, compared with 8% in the non-prescription group—about a 33% lower relative risk.
• For a broader category that included cognitive impairment (cognitive decline and dementia), the risk was about 36% in the prescription group versus 42% in the comparison group—roughly a 15% lower relative risk.

The study also reported that more frequent hearing aid use was linked with lower dementia risk, in a dose-like pattern. “While we didn’t find a difference in cognitive scores, our study suggests that for older adults with hearing loss, using hearing aids may lower the risk of dementia and cognitive impairment, benefiting brain health,” said Ryan. “Further studies are needed to understand the ways hearing aids may support memory, thinking, and brain health overall.”

Why no change in cognitive test scores?

Ryan noted that the lack of an observable cognitive “lift” was surprising, but one likely explanation is that, like the recent ACHIEVE study, many participants began the study with generally strong cognitive function, leaving less room to detect improvement on standard tests.

Important caveats to the study

The authors emphasized that this is an observational comparison—not a randomized trial—so it can’t establish that hearing aids prevent dementia. Another limitation: the group was largely healthy with good cognitive performance at baseline, meaning the results may not apply in the same way to people with poorer health or existing cognitive concerns.

The work was supported by the National Institutes of Health / National Institute on Aging, the Australian government, and Monash University.

Source: American Academy of Neurology