Key takeaways
- Hearing loss is one of 14 modifiable dementia risk factors named by the 2024 Lancet Commission, and it accounts for an estimated 7% of dementia cases worldwide.
- The ACHIEVE trial, published in The Lancet in July 2023, gave 977 adults aged 70 to 84 either hearing aids with audiologist care or health education classes.
- Across all 977 people, hearing aids did not slow three-year cognitive decline.
- In the 238 participants at higher risk, from the ARIC heart study, the hearing intervention slowed cognitive decline by 48% over three years.
- Over-the-counter hearing aids have been sold in U.S. stores without a prescription since October 2022 for adults with perceived mild to moderate hearing loss.
“Hearing aids have nothing to do with brain health.” That statement is false. Hearing loss is one of the largest risk factors for dementia that a person can change, according to the 2024 report of the Lancet Commission on dementia prevention, intervention and care.
The honest version of the answer has a wrinkle, though. The biggest trial so far found that hearing aids helped one group of older adults and made no measurable difference in another.
How is hearing loss linked to dementia?
Hearing loss is linked to dementia through several routes that researchers are still sorting out. The 2024 Lancet Commission, led by Gill Livingston of University College London, estimated that untreated hearing loss in midlife accounts for about 7% of dementia cases worldwide. Only high LDL cholesterol, also at 7%, ties it.
Researchers have proposed three explanations, and they may all be partly true:
- Straining to hear uses up mental effort that would otherwise go to memory and thinking.
- Less sound reaching the brain may speed up shrinkage in the areas that process it.
- People who cannot follow a conversation start skipping dinners, church and card games, and social isolation is a dementia risk factor on its own.
The third one is the one families notice first. A man who used to tell stories at every gathering starts sitting silent in the corner. It looks like withdrawal or confusion. Sometimes he simply cannot hear.
What did the ACHIEVE trial find?
The ACHIEVE trial (Aging and Cognitive Health Evaluation in Elders) is the largest randomized trial of hearing treatment and cognitive decline. Frank Lin of Johns Hopkins University led it, and The Lancet published the results on July 18, 2023.
The study enrolled 977 adults aged 70 to 84 with untreated hearing loss and no substantial cognitive impairment. Half received hearing aids fitted by an audiologist plus counseling. The other half met with a health educator about chronic disease prevention.
The results split in two:
| Group | Number | Effect of hearing intervention on 3-year cognitive decline |
|---|---|---|
| All participants | 977 | No significant difference |
| ARIC heart study participants (higher risk) | 238 | 48% slower decline |
| New healthy volunteers (lower risk) | 739 | No significant difference |
The 238 people from the Atherosclerosis Risk in Communities (ARIC) study were older and had more risk factors, such as high blood pressure and diabetes. Their thinking declined almost three times faster than the healthy volunteers’ did over the study period. In that group, hearing aids cut the decline nearly in half.
Why didn’t hearing aids help everyone in the study?
Hearing aids did not help the healthy volunteers within three years, most likely because their thinking was barely declining to begin with. A treatment cannot slow a decline that is not happening yet. The researchers are following that group longer to see if a benefit appears later.
There are other limits worth knowing. Participants and researchers both knew who got hearing aids, which can bias results. And three years is short for a disease that develops over decades. So the fair summary is this: treating hearing loss probably helps the brain, the evidence is strongest for people already at higher risk, and the full answer will take more years of follow-up.
How many people with hearing loss use hearing aids?
Most people with hearing loss do not use hearing aids. The ACHIEVE authors reported that fewer than 30% of adults with hearing loss in high-income countries use them, and fewer than 10% do in low- and middle-income countries. Age-related hearing loss affects about two-thirds of adults over 60 worldwide.
Cost, stigma and the belief that hearing loss is just part of getting old all keep that number low. The FDA rule allowing over-the-counter hearing aids, which took effect in October 2022, removed the prescription step for adults with perceived mild to moderate hearing loss. You can now buy them at a pharmacy or electronics store.
What should you do if you suspect hearing loss?
Get a hearing test. An audiologist can measure your hearing in under an hour, and many primary care offices can do a quick screen. Then:
- Ask whether over-the-counter hearing aids fit your level of loss, or whether you need prescription devices.
- Wear them. In ACHIEVE, people wore their hearing aids about 7 hours a day on average.
- Go back for adjustments. A poorly fitted hearing aid ends up in a drawer.
- Tell family members. Facing people when you talk, cutting background noise and speaking at a normal pace (not shouting) all help.
If you are a caregiver, ask about hearing before you assume a parent’s confusion is dementia. An older adult who misses half of every sentence can look forgetful when the real problem is in the ear.
Dementia Capable CARES includes hearing in its brain-health conversations because it is one of the few risk factors with a fix you can buy this week. Learn more at dementiacapablecares.org.
This article is educational and is not medical advice.
Sources
- Dementia prevention, intervention, and care: 2024 report of the Lancet standing Commission, The Lancet, July 31, 2024
- Hearing intervention versus health education control to reduce cognitive decline (ACHIEVE), The Lancet, July 2023
- Hearing Loss and Cognitive Decline: Results of the ACHIEVE Study, American Academy of Otolaryngology-Head and Neck Surgery
- Hearing Aids May Cut Dementia Risk in Those at High Risk, HealthDay via Drugs.com, July 18, 2023
