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The link between hearing loss and dementia has been in the news a lot lately. That’s because it’s big news, and it’s starting to change the game in terms of hearing protection and amplification. The World Health Organization (WHO) put hearing loss at the top of a list of twelve modifiable risk factors at play in the development of Alzheimer’s disease. Our government has restructured the prescription requirements around the purchase of a set of hearing aids, realizing the importance of continuing to bring access to hearing care to more and more people. It’s estimated that every $1 spent on treating hearing loss around the world returns $16 in productivity, preventive health care, and more, so governments are starting to pay attention to the science on hearing loss!
The Link Between Hearing Loss and Dementia
Studies concluded in the last few years have found a startling link between hearing loss and an earlier onset of cognitive decline and dementia. The more hearing loss, the greater the risk of dementia.
- Mild Hearing Loss – Twice as likely
- Moderate Hearing Loss – Three times as likely
- Severe Hearing Loss – Five times as likely
Until recently, it has not been clear whether hearing loss causes this increased risk, or whether there is some underlying reason that a person develops both hearing loss and dementia. More recent studies have started to indicate that treating hearing loss with hearing aids does, in fact, help delay and/or slow the progress of cognitive decline, suggesting that untreated hearing loss is the cause of the increased risk of dementia.
Cognitive Load Theory
One of the theories as to why hearing loss causes dementia involves what neuroscientists call “cognitive load.” When we have normal hearing, a part of the left side of our brain—the auditory cortex—automatically interprets the speech we hear, and commits it to short-term memory. When we have hearing loss, we start to use more parts of our brain to simply understand what we’re hearing, in addition to doing the rest of the work of considering meaning, formulating responses, and all the other thinking that goes along with having a conversation.
New Research On Subtle Hearing Loss and the Brain
A recent study conducted by researchers at Ohio State University found some surprising new information. The researchers used MRI scans to monitor the brain-behavior of participants ranging in age from 18 to 41 while listening to different types of sentences. Some of the sentences were very simple, while others were more complex. Surprisingly, the researchers discovered that those participants who showed barely-significant hearing loss (far less than would require treatment with hearing aids) used more of the right side of their brains than those with perfect hearing.
Basically, those participants with subtle hearing loss processed speech differently than their perfect-hearing peers and used more of their brains to do it. Their brain activity was more similar to that displayed by people aged 50 and up.
This new research highlights the importance of not only protecting our hearing throughout our lives but treating hearing loss as soon as hearing aids are recommended by a hearing care provider, according to the results of a hearing test.
Regular Hearing Tests
Regular hearing tests are crucial to maintaining our best health and well-being throughout our lives. The Better Hearing Institute, a non-profit organization, recommends getting a hearing test once every decade until age 50, and once every three years thereafter. Those in higher-risk professions or with a medical history indicating a higher risk of hearing loss should be tested even more frequently.
The benefits of regular hearing testing are twofold. For one, they can catch hearing loss early. A hearing care provider can tell from the results of a hearing test what the likely cause of any measured hearing loss may be. By catching 5 dBHL (decibels hearing level) of hearing loss when it appears, your hearing care provider can recommend the best ways to prevent further hearing loss going forward.
The other major benefit of a regular hearing test is to find out as soon as possible when it’s time to start wearing hearing aids. About one-third of those aged 60–69 should be wearing hearing aids, and for those 70 and up the fraction climbs to two-thirds. The sooner you start treating hearing loss, the easier it will be to get used to wearing hearing aids, and the lower your risk will be for cognitive decline and dementia.