A growing body of research has established a significant association between untreated hearing loss and cognitive decline, including dementia. The Lancet Commission on dementia prevention identified hearing loss as the single largest modifiable risk factor for dementia — accounting for approximately 8% of cases.
The research evidence
A landmark Johns Hopkins study following 639 adults over 12 years found that mild hearing loss doubled the risk of dementia, moderate loss tripled it, and severe hearing loss increased the risk fivefold. More recent research has confirmed this association across multiple populations.
Why might hearing loss affect cognition?
Researchers have proposed several mechanisms:
- Cognitive load: Struggling to hear consumes cognitive resources that would otherwise be used for memory and comprehension
- Social isolation: Hearing loss often leads to social withdrawal, and social isolation is itself a risk factor for cognitive decline
- Auditory deprivation: Reduced auditory input may lead to structural and functional changes in the brain over time
- Common pathology: Hearing loss and dementia may share underlying causes such as vascular disease
Can hearing aids help?
Several studies suggest that treating hearing loss with hearing aids may reduce the risk of cognitive decline. A 2023 randomised controlled trial (ACHIEVE study) found that hearing intervention significantly slowed cognitive decline in older adults at higher risk. While causality hasn't been definitively established, the evidence for treating hearing loss — for cognitive as well as audiological reasons — is compelling.
What this means for you
If you or a family member has untreated hearing loss, seeking assessment and treatment is prudent — not just for hearing quality, but potentially for long-term brain health. A hearing test takes 30 minutes and is the essential first step.