Hearing loss is often accepted as a normal part of aging, but several new bodies of research suggest that there could be a correlation between hearing impairment and cognitive function. More specifically, studies have found evidence that hearing loss could be a sign of dementia or Parkinson's. However, keeping yourself informed and addressing any auditory challenges could protect your brain health.
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Research links hearing loss and dementia.
Noting that hearing loss accounts for 8 percent of global dementia cases, making it the largest "modifiable risk factor" for the condition, researchers at the Johns Hopkins Bloomberg School of Public Health wanted to learn more about the connection.
In a Jan. 2023 study published in the Journal of the American Medical Association (JAMA), they found that among adults aged 65 and older, those with moderate to severe hearing loss had a higher prevalence of dementia.
More recent research, however, says that hearing loss starting at age 45 could increase one's dementia risk.
This study, published in The Journal of Prevention of Alzheimer's Disease, identified 12 modifiable risk factors in this age group, and hearing loss was the second most prevalent.
As the Alzheimer's Society explains, "Hearing loss may also mean that the areas of the brain that help us understand sounds and speech have to work harder to understand what sounds are. This additional effort may lead to changes in the brain that affects our memory and thinking abilities."
Using hearing aids could lower one's dementia risk.
Much research on hearing loss and dementia also recognizes that hearing aids can reduce the risk. The 2023 JAMA study, for example, found that wearing hearing aids decreased the prevalence of dementia in those participants with hearing loss.
Separate research from last year found that "hearing aids reduced the rate of cognitive decline in older adults at high risk of dementia by almost 50% over a three-year period," according to the National Institutes of Health (NIH).
"Hearing aid use was also associated with fewer memory problems and thinking problems independent of dementia," adds the Alzheimer's Society. They recommend seeing an audiologist for a hearing test if you're concerned about hearing loss or dementia risk.
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Research now links hearing loss and Parkinson's.
Now, new research out of the U.K. also links hearing loss and Parkinson's, albeit in a different way.
The study was published in November in the journal Parkinsonism and Related Disorders. Given that Parkinson's is the fastest-growing neurological condition in the world, researchers analyzed data from 159,395 participants in the U.K. Biobank who had no history of Parkinson’s. They then followed up with them roughly 14 years later and found that 810 participants were diagnosed with Parkinson's.
Looking more closely at these 810 people and their corresponding hearing tests, the researchers determined that for every 10-decibel increase in baseline hearing impairment, there was a 57 percent increased risk of Parkinson's, according to a press release.
"These findings are incredibly important; first, this is one of the first studies to look at how hearing impairments may increase risk for Parkinson’s or be an early warning sign of Parkinson’s," said Megan Readman, ESRC Post Doctoral Research Fellow from Lancaster University’s Department of Psychology and the lead author of the study.
"Secondly, as our findings suggest, hearing loss is intricately related to Parkinson’s so it may be beneficial for auditory functioning and the management of auditory impairment to be considered at the time of diagnosis and follow-up care," she noted.
However, Readman also pointed out that this study does not prove that hearing loss causes Parkinson's; it could be that there is a common underlying cause for both.
As is the case with dementia prevention, the importance of staying on top of your auditory health is one clear takeaway from this study.
