Can hearing aids also slow memory decline?

The hearing intervention did not clearly slow three-year memory and thinking decline for the whole group in this randomised trial. Both the hearing-aid group and the health-education group lost a similar small amount on a combined cognitive score. But the participants had been recruited from two very different pools, and a pre-planned comparison found a meaningful difference between those pools: the hearing intervention appeared to reduce cognitive change in the older, higher-risk adults recruited from a long-standing heart-health study, while no similar benefit appeared in healthier community volunteers. The authors interpreted this as possible benefit for people already at increased risk, but that conclusion is not settled and is separate from the neutral overall result.

Why hearing and thinking were compared

Hearing loss is common in later life and was already known from observational studies to accompany faster cognitive decline and a higher chance of dementia. But those earlier studies could only show an association, not that hearing loss was the cause or that treating it would change the course. The ACHIEVE trial was designed to test that directly. It was a randomized clinical trial—a study in which the participants are divided by chance into separate groups that compare different treatments or other interventions—set up in adults aged 70–84 who had untreated hearing loss and were free of substantial cognitive impairment.

What the two groups actually received

Across four community study sites in the USA, 977 adults were divided by chance into two groups: 490 received the hearing intervention and 487 received health education. The hearing group received audiological counselling and was fitted with hearing aids, with instructions to use them daily; they attended four one-hour sessions over two to three months and then refresher sessions every six months. The health-education group completed four one-hour sessions on preventing chronic disease and disability, including upper-body stretching, followed by more sessions every six months. Both groups had follow-up visits every six months until year three. The main measure was the three-year change in a global cognition standardised factor score from a comprehensive neurocognitive battery—in ordinary terms, a single combined score from a set of memory and thinking tests, with lower scores at year three than at the start meaning decline. Everyone was kept in the group they were first assigned to for the analysis, even if they did not fully follow the programme, so the result reflects being offered each intervention.

Overall result

When all 977 participants were pooled, the hearing group and the health-education group declined by nearly identical amounts on the cognitive score over three years. The small difference between them could easily have been chance, so for older adults with untreated hearing loss as a whole, the hearing intervention did not clearly reduce three-year cognitive decline in this trial. The authors wrote the same in their interpretation: the hearing intervention did not reduce 3-year cognitive decline in the primary analysis of the total cohort. No significant adverse events were attributed to the hearing intervention or the health education control.

Why the two recruitment groups matter

The participants came from two different backgrounds. One group was already enrolled in a long-standing observational study of cardiovascular health, the Atherosclerosis Risk in Communities (ARIC) study; these people were older, had more risk factors for cognitive decline, and started with lower cognitive scores. The other group were healthier volunteers recruited directly from the community. Because the two groups differed before the trial, the researchers planned in advance to examine them separately. That pre-specified sensitivity analysis found a significant difference in the effect: the hearing intervention appeared to reduce three-year cognitive change in the higher-risk ARIC group, while the healthier community volunteers showed no similar benefit. The authors interpreted this as evidence that hearing support might reduce cognitive decline over three years in people already at increased risk, but not in people at decreased risk. This is a subgroup signal from a secondary analysis, not the main result, and it needs confirmation; other sensitivity analyses that varied analytical parameters did not change the neutral overall result.

What to keep in mind

The trial was unmasked, meaning participants knew whether they received hearing aids or health education; this can influence expectations and behaviour. Most participants were White (88%), so the findings may not apply equally to more diverse populations. The main outcome was cognitive decline over three years, not a direct count of new dementia diagnoses, so the trial cannot claim that hearing aids prevent dementia. The overall result remains neutral, and the higher-risk subgroup finding is suggestive rather than proof.