Hearing Loss and Brain Health

While many people think of hearing loss as a minor inconvenience — turning up the TV, asking people to repeat themselves — it turns out hearing is far more closely tied to brain health than most people realise. Of the modifiable risk factors for dementia identified across the life course, hearing loss is one of the most consistently supported by the evidence, yet it rarely gets the attention given to blood pressure, diabetes, or physical activity.

Hearing Loss Can Impact Cognitive Health

Hearing does more than let us follow conversation. It shapes how much cognitive effort the brain spends moment to moment, how easily we stay socially connected, and — increasingly, the evidence suggests — how our cognitive function holds up as we age. Individual studies linking hearing loss to cognitive decline had been accumulating for years, but they didn't agree on much: different populations, different ways of measuring hearing loss, different outcomes measured. We set out to bring that evidence together.

What We Set Out to Find

We pulled together and analysed 40 studies from 12 countries, drawing on over 20,000 participants across the 36 studies with usable data. To keep the evidence clean, we only included studies that measured hearing loss objectively, using pure-tone audiometry, rather than by self-report — and we looked at its relationship to cognitive function across ten separate domains, from memory and processing speed to executive function, as well as to clinically diagnosed cognitive impairment and dementia.

What We Found

The associations were consistent, even if individually modest. People with hearing loss showed small but significant reductions across every cognitive domain we measured, including overall cognitive function and processing speed. The relationship strengthened further up the severity scale: hearing loss was associated with roughly double the odds of cognitive impairment in cross-sectional studies, and a smaller but still significant increase in risk in studies that followed people over time. For dementia specifically, the pattern held — higher odds in people with hearing loss, both cross-sectionally and over time, though the picture for Alzheimer's disease specifically was less clear-cut than for dementia overall.

Put simply: the size of each individual effect is modest, but it's consistent, it holds up across very different populations and study designs, and it's now in the same range as other well-established, well-accepted dementia risk factors.

Why Might Hearing Loss Affect the Brain?

There are a few competing explanations, and they're not mutually exclusive. One is a "cognitive load" account: a brain working harder just to decode degraded sound has fewer resources left for memory and thinking. Another points to the social consequences of hearing loss — conversation becomes effortful, people withdraw, and the loneliness and reduced social stimulation that follow are themselves established risks to brain health. A third possibility is that hearing loss and cognitive decline share a common underlying cause — the same age-related processes affecting both the ear and the brain, rather than one directly causing the other. Our data can't fully separate these explanations, and that matters for what comes next.

What This Means for You

Here's where we have to be honest about the limits of this kind of evidence: an association, even a strong and consistent one, isn't proof that treating hearing loss prevents dementia. Our meta-analysis couldn't test whether hearing aids or other interventions change that trajectory — that requires randomised controlled trials, not observational studies like the ones we reviewed. What it does tell us is that hearing loss deserves to sit alongside blood pressure, diabetes, and physical activity on the list of things worth paying attention to for brain health, not treated as an unrelated, purely cosmetic or convenience issue

What You Can Do

 

• Get your hearing tested, particularly from midlife onward — hearing loss is often gradual enough to go unnoticed until it's significant.
• Don't wait for hearing loss to become severe before addressing it; earlier action means less cognitive load and less social withdrawal in the meantime.
• If you're prescribed a hearing aid, think of it as a brain health tool as much as a hearing tool — and wear it consistently rather than only for special occasions.
• Notice if you're avoiding conversations or social situations because they've become tiring to follow. That withdrawal may be doing as much harm as the hearing loss itself.

Brain Health Chronicles will keep following this evidence as the trials needed to test these treatments directly are completed — for now, hearing deserves a place on your brain health checklist.

References

Loughrey, D. G., Kelly, M. E., Kelley, G. A., Brennan, S., & Lawlor, B. A. (2017). Association of Age-Related Hearing Loss With Cognitive Function, Cognitive Impairment, and Dementia: A Systematic Review and Meta-analysis. JAMA Otolaryngology–Head & Neck Surgery, 144(2), 115–126. https://doi.org/10.1001/jamaoto.2017.2513