Hearing Loss and Dementia

If living with hearing loss wasn’t already hard enough for the 1 in 6 Australians who currently suffer from it, scientists have recently discovered potential links between hearing loss and the occurrence of cognitive problems, including dementia.

Researchers from the John Hopkins School of Medicine in Baltimore partnered with a handful of other US research institutions to carry out the groundbreaking experiment. Led by Frank Lin, M.D., an otologist and epidemiologist at Johns Hopkins University, the study followed 639 American adults aged 39 – 90, between the years of 1990 and 1994.  Each participant underwent a series of tests to establish their cognitive and aural abilities. They were then closely monitored closely for any signs of developing Alzheimer’s and dementia until May 2008.

At the start of the study, not one of the 639 participants showed any signs of dementia or Alzheimer’s. 125 of them had ‘mild’ hearing loss, 53 had ‘moderate’ hearing loss and just 6 had ‘severe’ hearing loss. The rest could hear perfectly. All were mentally sharp and emotionally stable.

After roughly 12 years, a mid-progress report found that:

  • 58 out of the 639 (about 9%) had been diagnosed with dementia. 37 of these cases were confirmed Alzheimer’s
  • Those who had hearing loss at the start of the study were more likely to develop dementia. The greater the hearing loss, the greater the risk of developing dementia
  • For every 10 dB of hearing lost during the study, the likelihood of dementia jumped by 20%
  • Those with moderate hearing loss had triple the risk of developing dementia

Unfortunately, these findings have been recently supported by another, completely independent study. Completed earlier this year, this study followed 1984 people over a period of 16 years. It yielded similar results to earlier research, plus a few additional insights. One of it’s most important findings was that decline in memory and thinking capabilities occurs an estimated 40% faster in those who suffer from hearing loss than in those who have perfect hearing.

It is crucial to remember that simply being at increased risk does not mean a person with hearing loss is definitely going to develop dementia. As Dr. Lin from John Hopkins points out, “I have a [90-year-old] grandmother who’s had a moderately severe [hearing] loss for many years now. She’s as sharp as a tack. I was talking to her about [my] research and she looks at me and says, ‘Are you telling me I’m definitely going to get dementia?’ I said ‘[Not by] any means.’”

There is currently no known reason why hearing loss increases the risk of developing dementia, but researchers do have a few theories, such as:

  • “Cognitive overload” – the brain becomes run down because it has to overcompensate to hear
  • Hearing loss might affect brain structure, causing cognitive problems
  • The social isolation experienced by those with hearing loss could potentially contribute to a decline in mental abilities, leading eventually to dementia
  • Dementia and hearing loss could simply be linked, meaning they have similar causes and involve joint processes.

The good news

Although these findings may be depressing, there is a silver lining. This research will become invaluable in the coming years and may very well contribute to the search for a potential Alzheimer’s cure or preventative measure.

Dr. Lin and his team are planning a new study to work out whether providing state-of-the-art hearing loss treatment can delay or even prevent dementia. Such a breakthrough would improve the lives of millions of people.

While the results of further studies could be years away, we do know that it is now more important than ever to get regular hearing checks and to take immediate action if you are experiencing hearing loss. It could one day mean all the difference to your mental health.

Do you suspect you might be suffering from a degree of hearing loss? It's time to take action. Call us on 1300 656 858 and book a hearing assessment at your local Connect Hearing clinic today.