ACHIEVE Study: Can treating hearing loss slow cognitive decline?

ACHIEVE study overview

The ACHIEVE study is the first large randomised controlled trial to test whether treating hearing loss slows cognitive decline. Across all 977 older adults, hearing intervention did not slow three-year cognitive decline overall. But in a subgroup already at higher risk, it slowed decline by around 48%, a promising signal that needs further confirmation.

A question decades in the making

For years, study after study told us the same thing: people with hearing loss are more likely to experience cognitive decline. What none of them could tell us was whether the reverse held true. If we treat the hearing loss, do we change what happens to the brain?

That is the question ACHIEVE, the Aging and Cognitive Health Evaluation in Elders study, was built to answer. And it remains one of the most important clinical trials around hearing and brain health so far.¹

The first study of its kind

ACHIEVE was the first large randomised controlled trial to test whether treating hearing loss can slow cognitive decline. Researchers followed 977 adults aged 70 to 84, all with untreated mild-to-moderate hearing loss and none with significant cognitive impairment at the outset, across four US sites for three years.¹

Half were randomly assigned to a full hearing intervention: hearing aids, fitting, and ongoing audiologic counselling and support.

The other half took part in a health education programme instead.¹

An honest headline

Here is where care matters. Across the whole group, the hearing intervention did not significantly slow cognitive decline over three years. The trial's primary result was null.¹

It would be easy to stop there and read the study as a disappointment. But that would miss the more interesting story sitting inside the data.

Where it mattered most

ACHIEVE drew its participants from two groups. One was a set of healthy community volunteers. The other, around 238 people, came from an existing heart-health study and were older, carrying more risk factors for cognitive decline.¹

Among that higher-risk group, the result was striking. Hearing intervention slowed cognitive decline by roughly 48% over three years. The healthier participants, by contrast, declined so little across the study that there was barely any decline left for the intervention to show.¹

In other words, hearing care appeared to help most exactly where the risk was greatest. These findings sit alongside a wider body of evidence that identifies hearing loss as one of the potentially modifiable risk factors for dementia², and raises the possibility that acting on it could help protect brain health.

That link is still being established, and ACHIEVE is among the strongest signals we have that hearing care may be part of the answer.

What it does, and does not, tell us

The 48% comes from a prespecified part of the study population, not the trial as a whole. That makes it a powerful signal, and a genuine reason for optimism, but not yet proof that treating hearing loss protects cognition for everyone.

The honest reading is the one ACHIEVE's own investigators offer: hearing intervention shows real promise for protecting the brain in those most at risk, and everyone stands to gain from the better communication and connection that came with it.

Want to know more about the role of hearing within dementia prevention?

We spotlight the issue here