Source: The Conversation – UK – By Emma Broome, Senior Research Fellow, University of Nottingham
Hearing loss and dementia affect millions of people worldwide. But headlines describing hearing loss as the “leading mid-life risk factor” for dementia can be misleading. They often oversimplify complex science, and risk confusing people who are trying to understand what hearing loss can mean for brain health.
Research shows that hearing loss and cognitive decline frequently occur together. Cognitive decline refers to worsening memory and thinking skills.
While these two conditions are linked, we still do not fully understand why. Several biological and social factors are likely to be involved, and they probably interact in complex ways. What we do not yet have is clear evidence that hearing loss directly causes dementia.
Hearing loss is extremely common. Around 430 million people worldwide live with disabling hearing loss, and this number is expected to rise to more than 700 million by 2050. Dementia affects 57 million people globally, with prevalence increasing with age. As populations live longer, more people will experience one or both conditions.
Some of the confusion arises from how dementia risk is calculated and reported. Age and genetics account for much of overall risk, alongside factors such as cardiovascular health, education and social isolation. Hearing loss is one part of this broader picture, which means its role can be misinterpreted when statistics are presented without context.
Another source of misunderstanding is how research findings are described. The Lancet commission on dementia uses a measure called the “population attributable fraction”. This estimates how many dementia cases might be linked to a particular factor, in this case hearing loss. It does not mean that a person with hearing loss will develop dementia.
The figure reflects both how common hearing loss is, and how strongly it is associated with dementia. Because hearing loss is so widespread, it can appear to account for a large proportion of cases at population level, even though the individual risk for most people remains relatively modest.
Clear communication is therefore essential. Hearing aids and other devices should not be promoted as guaranteed ways to prevent dementia. Their main value lies in the broader benefits they provide, including improved communication, stronger social connections and better quality of life. These factors can support cognitive health, but they are not proven protective treatments.
Overstating the link between hearing loss and dementia may create unrealistic expectations. It may also discourage some people from seeking help because of stigma – particularly if hearing loss becomes framed primarily as an early sign of cognitive decline, rather than as a common and treatable condition.
How hearing loss might affect the brain
Researchers have proposed several ways in which hearing loss could influence cognitive decline. Hearing difficulties do not simply make conversations harder. They can also alter how the brain processes information.
When sounds are difficult to hear, the brain must work harder to interpret them. This increased effort may leave fewer mental resources available for memory and thinking. Over time, reduced sound input may also affect how certain brain regions function, similar to how a muscle weakens when it is used less.
Hearing difficulties can also affect social participation. Struggling to follow conversations may lead to withdrawal, loneliness or depression, all of which are linked to a higher risk of dementia. At the same time, shared underlying factors such as ageing, vascular disease and genetics may contribute to both hearing loss and dementia.
The picture is complex. These processes are likely to interact differently across people and stages of life, meaning dementia risk is highly individual rather than uniform.
Can hearing aids prevent dementia?
Hearing aids and cochlear implants improve access to sound. However, evidence that they prevent dementia or significantly slow cognitive decline remains limited.
Clinical trials have generally been small and inconclusive, while observational studies show mixed results. Some suggest slower cognitive decline among long-term hearing aid users, but these studies cannot fully account for other influences such as health status, education or income.
That does not mean hearing aids are unimportant. They can make a substantial difference to daily life by helping people follow conversations, remain socially connected and maintain independence. For people already living with dementia, improved hearing can support communication and wellbeing.
Hearing loss often occurs alongside dementia, and when unaddressed it can reduce the effectiveness of other forms of support. Difficulty hearing can make group activities, therapy sessions and social programmes harder to engage with. By improving access to sound, hearing aids may help people benefit more fully from existing care.
Most research on hearing loss and dementia has been carried out in high-income countries. Many studies exclude minority ethnic groups, people in lower-income settings and those living in care homes. This matters because the risk, experience and management of both conditions vary across populations.
Around 80% of people with hearing loss live in low and middle-income countries, and the fastest growth in dementia is expected in these same regions. Without more inclusive research, understanding will remain incomplete and interventions may fail to reach those who need them most.
The relationship between hearing loss and dementia is still evolving. What is clear is that hearing loss affects far more than just cognition. Supporting people to hear better can help them stay connected, engaged and independent. These benefits matter at every stage of life.
Emma Broome receives funding from an NIHR Development and Skills Enhancement Awards (NIHR306142) and a research grant from WS Audiology A/S.
– ref. Hearing loss is often called a dementia risk factor – here’s what the research really shows – https://theconversation.com/hearing-loss-is-often-called-a-dementia-risk-factor-heres-what-the-research-really-shows-276246