In this project, Professor Sally Dawson and a team of dementia and hearing researchers at University College London review the largest database of existing genetic studies, to understand more about the link between dementia and hearing loss.
Project start date: March 2021
Project end date: July 2024
Read about the project outcomes here.
About the project
Recently, a link has been found that suggests people who develop hearing loss as they get older are at a higher risk of also developing dementia. As yet, we don’t understand the nature of this link and there’s no clear-cut evidence to support or disprove any of the theories posited by researchers.
As current treatment options for both conditions are limited, there is an urgent need to better understand the link and its implications for developing better treatments.
How it works
In this study, dementia and hearing researchers will address this lack of evidence. They’ll analyse the largest existing genetic studies for which there is data on both hearing ability and dementia status, from hundreds of thousands of people.
By using modern genetic analysis techniques, they will look for evidence of common inherited causes that might underlie both hearing loss and dementia. They’ll also look at interactions between hearing, dementia and other medical data collected in these studies, such as cardiovascular health and brain imaging data, to see if they play a role.
In a subset of people in the study, these measures have been repeated over several years, allowing the researchers to track the progression of dementia in people with and without hearing loss to see if there are differences.
How will this research benefit people at risk of hearing loss?
The findings from this project may help to better define the link between hearing loss and dementia, providing a better understanding of both conditions. This will speed up the development of new treatments to reverse or slow the progression of both hearing loss and dementia.
What we’ve learned so far
The researchers found that both dementia and hearing loss involve changes or damage to small blood vessels and that these changes partially explain why people with cardiovascular disease and diabetes are at higher risk of both conditions suggesting a common mechanism.
They also found that people at higher genetic risk of hearing loss develop full dementia more quickly than people at lower risk of hearing loss.
The analysis of MRI images from participants monitored over time suggests that tinnitus and hearing loss are associated with changes in the brain and that these effects are different for tinnitus than they are for hearing loss. The results provide an insight as to the causes and effects of hearing loss and tinnitus on brain function.
About the researcher
Professor Sally Dawson is Professor in Molecular Genetics of Hearing Loss at the Ear Institute, University College London. She was awarded an RNID Discovery Research Grant in 2021, which was co-funded in partnership with Alzheimer’s Research UK.
I hope [my research] will help us to understand why people lose their hearing. And that this information will, ultimately, allow us to develop treatments or prevent hearing loss.”
