To understand the link between hearing loss and Alzheimer’s disease, it is helpful to know what a “risk factor” is. The presence of one or more risk factors for a particular disease increases the statistical likelihood of developing that disease. A risk factor, however, does not cause the disease.
A Closer Look
A recent study at Johns Hopkins Hospital found that mild hearing loss doubled the risk for dementia. Moderate loss tripled that risk. People with severe hearing loss were five times more likely to develop dementia.
Why is this so? Some experts speculate that the part of the brain related to hearing and interpreting sound may experience changes when hearing declines. These changes could be related to the effects of Alzheimer’s. It’s also possible that, because the brain works harder to process aural stimuli when there’s hearing loss, it has fewer resources to apply to other cognitive work.
In a story about dementia and hearing loss that appeared recently in the New York Times, Washington University School of Medicine researcher Johnathan Peelle, PhD, discusses the changes that may take place in the brain due to hearing loss: “The brain is made up of all these interconnected networks, and if you throw off the balance a little bit over years and years, that may have these widespread effects that are hard to measure clearly.”
And here’s another reason that hearing loss is a risk factor for dementia: People with hearing loss often withdraw socially, either because they are embarrassed by the condition or because it’s simply too difficult to participate—or a combination of both. It’s certainly true that loneliness and isolation are themselves risk factors for dementia.
Addressing the Risk
According to the Hearing Loss Association of America, near 50 million people in the United States have some level of hearing loss. This loss can be caused by a number of things: genetic predisposition, medications, brain injury, infections, and exposure to noise, to name a few. Difficulty hearing, or an inability to hear, high-pitched and soft sounds may indicate that delicate hair cells in the ear, called stereocilia, have been damaged. Tinnitus, or ringing in the ears, also can be an indicator of hearing loss.
Here’s another question to consider: Why do so many Americans with hearing loss choose not to use hearing aids? Cost is one significant obstacle; many health insurance policies don’t cover the cost of hearing aids, though this could soon change as several initiatives are currently pushing for new policies. Hearing aids carry a stigma, too, as they often are viewed as symbols of physical decline and aging. And hearing aids have a reputation for causing aural complications even as they work to improve the ability to hear. Older models can whistle and beep when poorly adjusted; others may make it difficult for the wearer to differentiate ambient noise from intimate conversation. Newer versions of hearing devices have eliminated many of these complications, however.
Decreasing the Risk
If hearing loss is a risk factor for cognitive disease, can the use of a hearing aid diminish that risk? A study funded by the National Institute on Aging is working to answer that question. A first-ever randomized control trial will follow a cohort of older adults—some to be treated for hearing loss with hearing aids, others with a nutritious diet, and exercise. Researchers will be looking to see which group is less likely to develop dementia.
Just as hearing loss doesn’t cause Alzheimer’s, a hearing aid won’t prevent the disease. In the same New York Times story, Peelle puts it this way: “You’re never going to stop Alzheimer’s disease with a hearing aid, but you may help people to function better by supporting their cognition that way.”
Research may well show that we can reduce the risk of cognitive disease by paying attention to hearing health. Certainly, preventing hearing loss is an important part of preventive health care. If you already have hearing loss, you may be able to help your brain—and help maintain a rich and satisfying social life—by using a hearing aid. And if a loved one with Alzheimer’s disease or other forms of dementia also has hearing loss, a hearing aid may well improve quality of life and help protect existing cognitive abilities.
We’re experts in Alzheimer’s care, working to help ensure our residents are living their best lives. If you’d like to talk with someone about Alzheimer’s disease, dementia, and hearing loss, we’d be happy to offer information and answer your questions. Call (314) 542-2500.