We discover the link between hearing loss and dementia, as new studies report that difficulty hearing speech could be a risk factor
Words: Katy Sunnassee | Images: Shutterstock | Study: World Health Organization
Hearing impairment affects around 1.5 billion individuals worldwide, and if you’re hard of hearing, you may be at a higher risk of dementia. A study published in 2021 and led by University of Oxford researchers looked at 82,000 participants over age 60, found the link between hearing loss and dementia, discovering that difficulty hearing spoken conversations is associated with up to a 91 per cent increase in dementia risk.
‘Dementia affects millions of individuals worldwide, with the number of cases projected to treble in the next few decades. However, there is growing evidence that developing dementia is not inevitable and that the risk could be reduced by treating pre-existing conditions,’ says Dr Thomas Littlejohns, senior epidemiologist at the Nuffield Department of Population Health (NDPH), and senior author of the study.
A major component of hearing impairment is difficulty hearing speech in noisy environments – also called speech-in-noise (SiN) hearing impairment. This can have a large impact on the day-to-day functioning of people affected, who can struggle to follow conversations or hear announcements in noisy environments. However, until now it was unclear whether difficulty hearing speech-in-noise was associated with developing dementia. The above-mentioned study, published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, showed how over an 11-year follow-up of men and women from the UK Biobank study, 1,285 participants developed dementia. Those who had been classified as having “insufficient” or “poor” speech-in-noise hearing were associated with a 61 and 91 per cent increased risk, respectively, of developing dementia, compared to a normal level of speech-in-noise hearing.
Hearing loss and dementia
‘Difficulty hearing speech in background noise is one of the most common problems for people with age-related hearing impairment. This is the first study to investigate its association with dementia in a large population,’ says lead author of the study, Dr Jonathan Stevenson, former MSc student at NDPH and Otolaryngology-Head and Neck Surgery trainee with the Royal Australasian College of Surgeons.
Whether SiN is a symptom of, or prerequisite to, dementia is important to note. Due to the length of time it takes to diagnose dementia, there is a risk that some patients in the study may already have had unknown dementia progression prior to their SiN diagnosis. This could adversely affect the performance on a hearing test, for example. However, the study explored this association and found that dementia would present itself earlier (within three years) in a pre-diagnosed patient, whereas the association would be less likely over 6-9 years.
The results of the Oxford-led study suggest that speech-in-noise hearing impairment could represent a promising target for dementia prevention. ‘While most people think of memory problems when we hear the word dementia, this is far from the whole story,’ says Dr Katy Stubbs from Alzheimer’s Research UK. ‘Many people with dementia will experience difficulty following speech in a noisy environment – a symptom sometimes called the “cocktail party problem”. This study suggests that these hearing changes may not just be a symptom of dementia, but a risk factor that could potentially be treated.’
If you have concerns about your hearing, speak to your GP or visit a hearing test centre.
