A large Danish study confirms growing body of evidence
By Deborah Jeanne Sergeant
A recently released Danish study of 570,000 people over 14 years identified untreated hearing loss as increasing the risk for dementia compared with people with no hearing loss or those with treated hearing loss.
The study doesn’t surprise Carolynne Pouliot, doctor of audiology and owner of Hearing Aide Works Audiology in Penfield, who referenced a 2011 study that stated even a mild untreated hearing loss increases the risk of dementia by 200%; moderate hearing loss and severe hearing loss by 500%.
“People may still ‘get by’ with their hearing loss and be at risk,” Pouliot said. “None of the participants had dementia when they started. At the end, that’s what they found.”
She referenced several other studies that indicate similar results, including a Duke University study by Murali Doraiswamy, which indicated that even people diagnosed with dementia who also have hearing loss find that treating their hearing loss is twice as effective as medication prescribed to slow cognitive decline.
“Walking around with untreated hearing loss has so many risks,” Pouliot said. “The best thing you can do to prevent cognitive decline or to slow it if you’re diagnosed is to treat any hearing loss present. The hidden benefits of treating hearing loss show up in research again and again.”
Introducing hearing aids at that point can also make their use more effective so that the brain becomes accustomed to their input.
For those who would develop cognitive decline, earlier adoption of hearing aids to treat hearing issues can delay onset of dementia by seven years.
“You can buy yourself seven years by treating hearing loss,” said Matthew S. MacDonald, doctor of audiology and owner of MacDonald Audiology in Rochester.
Hearing loss tends to isolate people as they withdraw from social situations because they cannot participate in conversation and understand what’s going on around them the way they used to. But MacDonald said that it’s not only the lack of socialization.
“An interesting study done at University of Colorado showed that the brain with hearing loss actually had changed as a result of the hearing loss,” MacDonald said. “Parts of the auditory cortex meant to be used for hearing were being used for pattern recognition. They showed that when those individuals treated their hearing loss, within six months, those people’s brains reorganized themselves to their original designation.
“If you have problems with your hearing, you’ll use other modalities to make up for it, like lip reading. We don’t want this cross-modal brain use. People need to use all of their cognitive resources. Hearing loss can drain your cognitive resources. If you have to struggle to pay attention to what someone is saying, it doesn’t leave resources left for memory and cognitive processing.”
MacDonald wants more people to receive a baseline hearing exam, even before the TV volume creeps up and they feel “everyone mumbles.” Most people who experience hearing loss over time are not aware of its encroachment. But those who receive an exam and are told that they hear just fine can know later if their hearing has changed.
Sarah Hayes, doctor of audiology, Ph.D. and assistant professor of otolaryngology at URMC, said that fewer than 30% of people with hearing loss who could benefit from using hearing aids obtain and use them.
“People with hearing loss typically wait an average of seven years before seeking help,” she added. “As an audiologist, I want people to know that not only is it important to protect your hearing when you are exposed to loud noise, whether you are attending a loud music concert or using your lawnmower, but if you suspect that there has been a change in your hearing or you’ve noticed that you are struggling to hear what others are saying to you, make sure that you get your hearing tested. Identifying and managing hearing loss is very important for our brain health.”
She hopes that additional study will bring a better understanding of the link between untreated hearing loss and cognitive decline. Her lab is studying how hearing loss alters the brain’s regions that control memory, learning and executive function, all of which dementia negatively impacts.
Joe Kozelsky, retired audiologist, honorary board member of the Hearing Loss Association of America Rochester Chapter in Fairport and author of the book “Hearing, Hearing Loss and Hearing Aids,” thinks that the link between untreated hearing loss and increased risk for dementia should prompt people to take care of their hearing loss. But in addition, improving quality of life should be reason enough.
“Start with a bonafide professional rather than an over-the-counter aid or responding to ads on TV,” Kozelsky said.
Muffled hearing could have other reasons such as a build-up of wax or other problem.
Nonetheless, Kozelsky sees merit in treating hearing loss for the reasons the growing body of evidence seems to indicate.
“You want to do what you can to avoid the social isolation of hearing loss,” he said. “That’s harmful and does lead to sensory deprivation and withdrawal.”