The Hidden Link Between Hearing Loss and Dementia

If you've noticed yourself turning the TV up a little louder each year, or asking people to repeat themselves more often, you're not alone — and it's worth paying attention to. Over the past decade, hearing loss has become one of the most talked-about “modifiable risk factors” for dementia. But what does that actually mean, and how worried should you be? Here's a clear-eyed look at what the research really shows.

What is cognitive decline?

Cognition is essentially how your brain thinks — your ability to learn, process information, pay attention, and remember things. When cognition declines noticeably, it can show up as memory lapses, trouble concentrating, or difficulty following conversations.

When this decline becomes severe enough to interfere with daily life, it may be diagnosed as dementia. Dementia isn't a single disease — it's a collection of symptoms that can arise from several different underlying conditions, with Alzheimer's disease being the most common. A diagnosis typically requires memory loss alongside problems in at least one other area of thinking, such as attention, language, or social understanding.

There's no cure for dementia, and cases are rising globally — nearly 10 million new diagnoses occur worldwide each year. Because there's no curative treatment, researchers have shifted focus toward modifiable risk factors: things that, if addressed, might help delay or reduce someone's risk. Hearing loss is one of the factors currently being investigated in this space.

So what does the research actually say?

A landmark 2017 article in The Lancet first put hearing loss on the map as a potential dementia risk factor, and it's been a hot topic in both research and the media ever since. Since then, a steady stream of studies has explored the connection — and the honest answer is that the picture is more complicated, and more cautious, than headlines often suggest.

An association, not a proven cause. Most of the studies in this field are observational — they look at large groups of people over time and note that those with more hearing loss tend to show more cognitive decline. That's a real and replicated pattern. But observational studies can't prove causation. It's genuinely unclear whether hearing loss contributes to cognitive decline, whether early cognitive decline contributes to hearing difficulties, or whether some other shared factor — such as general health, education, or ageing processes in the brain — is driving both. Researchers are still actively investigating all three possibilities.

The evidence on hearing aids is mixed. This is probably the most important nuance for the public to understand. Some observational studies have found that hearing aid users show less

cognitive decline than non-users. When researchers ran a randomised controlled trial — the gold standard for proving cause and effect — the results were less clear-cut. The 2023 ACHIEVE trial compared a group given hearing aids and counselling against a control group. Overall, there was no significant difference in cognitive decline between the two groups, though a secondary analysis suggested a possible benefit in a subgroup at higher cardiovascular risk. A smaller Australian study (ENHANCE) found hearing aid users showed more cognitive stability than non-users, but the sample was small and the authors called for larger, longer studies.

What major health bodies recommend

Given this mixed picture, professional and government health bodies have been careful not to overstate the evidence:

The World Health Organization concluded there is currently insufficient evidence to recommend hearing aids specifically for the purpose of reducing dementia risk — but it does recommend that older adults be regularly screened for hearing loss as part of general healthy ageing care.

The UK's National Institute for Health and Care Excellence (NICE) similarly states there is no good evidence that hearing loss causes dementia, or that hearing aids prevent it — but notes hearing aids clearly improve communication and quality of life, which may in turn help people manage dementia better if it does develop.

The New Zealand Audiological Society (NZAS), in its August 2024 position statement, echoes this careful approach: it confirms an association exists between hearing loss and cognitive decline, but stresses there isn't yet enough evidence to draw firm conclusions about cause and effect, and explicitly encourages its members not to overstate the risks of untreated hearing loss.

Why looking after your hearing still matters

None of this nuance means hearing health is unimportant — quite the opposite. Hearing loss has well-established effects on communication, social connection, mental wellbeing, and quality of life, regardless of any link to dementia. People with untreated hearing loss may withdraw from conversations, feel isolated, or find it harder to stay engaged in their communities — and social isolation itself is a recognised risk factor for cognitive decline.

There's also a practical, everyday reason to take hearing seriously if dementia is already a concern in your family: hearing loss and dementia often occur together in older age, and each can make the other harder to manage. Untreated hearing loss can worsen confusion or communication difficulties in someone living with dementia, and dementia symptoms can complicate hearing assessment and treatment. Good audiology guidelines now recommend that a hearing check be considered as part of a dementia assessment, partly to rule out hearing loss as a confounding factor.

What you can do

If you're concerned about memory or cognitive changes, in yourself or a loved one, start by talking to your GP. Organisations such as Dementia New Zealand, the New Zealand Dementia Foundation, and Alzheimers New Zealand all offer further information and support.

If you're concerned about your hearing, getting a hearing test from a clinic or audiologist is a simple, low-risk step — whatever the cause of any difficulty, addressing it early tends to help.

The bottom line

Hearing loss and cognitive decline are clearly linked in population research, but exactly why remains an open scientific question at this point in time. What's not in doubt is that healthy hearing supports communication, connection, and quality of life at any age. Taking care of your ears is a sensible step worth taking on its own merits, without needing to wait for the dementia question to be fully resolved.

This article is for general information purposes only and is not a substitute for professional medical advice. If you have concerns about your hearing or cognitive health, please consult a qualified audiologist or your doctor.