DEAFNESS AND DEMENTIA... WHAT HAVE YOU HEARD?

THERE'S A LOT OF NOISE BEING MADE ABOUT A POSSIBLE LINK BETWEEN HEARING LOSS AND DEMENTIA. BUT WHAT DOES THE SCIENCE HAVE TO SAY?

- by TOM IRELAND

In recent years, there has been a huge surge of interest in the link between our hearing and our chances of getting dementia.

Stories in the press have suggested that up to a third of dementia cases may be caused by hearing problems. TV doctors are telling viewers that having a hearing test can help prevent the syndrome, while adverts for hearing aids are claiming the devices can slow cognitive decline.

But, as so often is the case, the relationship between our hearing and our brain health is complex. And while there are clear benefits to treating hearing loss, the evidence that hearing aids can prevent dementia isn’t quite what it seems.

FINDING A CONNECTION

Studies linking the decline or loss of senses to poorer cognitive ability date back to the 1990s, when a research project known as the Berlin Aging Study first found an association between declines in hearing or vision and declining brain or cognitive function. But recent interest in the link between hearing and dementia can be traced back to a major report called ‘Dementia Prevention, Intervention and Care’, published in The Lancet in 2017.

The widely-read report declared for the first time that hearing loss was the biggest ‘modifiable risk factor’ for dementia. In other words, something that contributes to our chances of getting the disease that we can do something about (unlike our genetics or family history). The report suggested that hearing loss might play a bigger role in dementia than poor diet, lack of exercise, poverty or social isolation — and that treating it could prevent as many as eight per cent of dementia cases worldwide.

Although the report acknowledged that the exact nature of the link was unclear, the idea that hearing loss actually