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Researchers Suggest a Link Between Hearing Loss and Dementia

Sometimes it’s the enemies you can’t see that can do the most harm. Hearing loss (or loss of any of the senses), if untreated, almost inevitably leads to depression embedded in a sense of growing isolation.

From there, it’s a short step to mental decline which – again, should it remain untreated – could evolve into early onset dementia.

Those who were born deaf or became so relatively early in life likely learned to communicate, via sign language for example, and so can maintain a connection with the world around them.

Conversely, the person experiencing a hearing deficit later in life – whether work-related or resulting from the aging process – may be reluctant to admit there’s a problem.

This often means evading medical care, even as the rift between them and their loved ones and the world at large continues to widen, leaving that person feeling ultimately alienated and alone.

Is there a link between hearing loss and dementia?
Can hearing loss exacerbate dementia?

Drawing the Connection Between Hearing Loss and Dementia

Until Dr. Frank Lin came on the scene, this link was not given serious consideration. Dr. Lin, M.D., Ph.D., an assistant professor at the Johns Hopkins University Schools of Medicine and Public Health, presented a paper on the subject at the 2016 annual conference of the American Association for the Advancement of Science (AAAS).

For those wondering, “But wouldn’t this link be obvious to doctors, let alone to gerontologists?” the answer is “No, not really.”

There had been prior (but apparently not sufficiently prolonged or in-depth) studies whose results suggested a link but, as Lin pointed out in his presentation, the process and pattern of hearing loss has become so common in an aging and now longer-lived population that physicians failed to appreciate the significance of a possible connection.

As Lin also stated, according to a 2016 article in The Guardian newspaper, “The vast majority of dementias in late life are multifactorial, but the role of hearing loss has just not been studied.”

Lin also admitted that, of the numerous theories advanced to explain the link between hearing problems and dementia, nothing is yet proven. Still, that there is a link is at least generally accepted by healthcare professionals, as evidenced by other studies inspired by Lin.

The Study’s Findings

Lin’s paper was the result of a study created by him and several other scientists in 2013. Their observations were drawn from a study involving nearly 2,000 subjects (average age of 77). These subjects’ cognitive abilities (including, concentration, memory, and planning skills) were evaluated. Among the findings:

  • Having to strain to hear causes stress to certain portions of the brain which are then overworked, resulting, potentially, in a loss of gray matter in the left temporal lobe, the segment of the brain associated with spoken language and vocabulary.
  • This strain can also result in damage to working memory (that is, short-term or recent – memory).
  • Those experiencing untreated hearing loss were believed to be an estimated 30% to 40% more likely to eventually suffer from cognitive decline that could develop into full dementia.

The Figures on Hearing Loss in America

According to the Hearing Loss Association of America (HLAA), as of 2017 there were an estimated 48 million people in the US experiencing hearing issues. Additionally, an American in their 70s has roughly a 67% chance of having hearing loss. That said, up until quite recently, many Americans would have refrained from pursuing treatment for hearing loss for the following reasons:

  • Simple denial. There’s nothing unnatural about hearing loss or changes in vision, but these are not changes that everyone is comfortable admitting to.
  • It could be that the person experiencing the hearing loss doesn’t realize how marked it is, or is too quick to simply label it as merely age-related.
  • Few insurance policies cover the costs of treating hearing loss, and Medicare certainly doesn’t. Under Medicare’s Plan B, coverage of diagnostic hearing and balance exams applies, but only if those tests are first ordered by the patient’s physician or some other recognized healthcare professional. Even if the tests are authorized, and the results indicate the patient would need medical treatment, the patient is then on their own; Medicare does not cover medical expenses for hearing exams, hearing aids, or exams for fitting hearing aids.
  • Until recently, the cost of hearing aids (anywhere from $900 per ear to more than $3000 per ear) has put them out of most people’s economic reach.
  • For those who do try to buy a hearing aid, the purchase process can be difficult. Salespeople, eager to make a commission, may attempt to sell a confused client a bundle of services they don’t need or a product that isn’t well-suited to the client’s needs.
  • Also, until recently, the U.S. has shown great reticence about exploring and generating more affordable options for those with hearing issues.

The Good News – and Yes, There Is Some

Presumably, due at least in part to the findings of Dr. Lin and his team, Senators Elizabeth Warren (D-Massachusetts) and Chuck Grassley (R-Iowa) jointly wrote an article advocating for reform of the U.S. hearing aid market, which was published in the March 2017 issue of JAMA Internal Medicine.

The good news is that that article, along with the undeniable results of an increasing number of studies, has led the Food and Drug Administration (FDA) to expand their list of approved hearing loss devices, which continues to result in lower prices, while also serving as an incentive for development of yet more effective and budget-friendly alternatives.

Could Cognitive Damage Be Reversible?

Even more good news came out of a study conducted in France by researcher Isabelle Mosnier of Assistance Publique-Hôpitaux de Paris. The results of the study were first published in the December 2015 issue of JAMA Otolaryngology-Head & Neck Surgery.

Astoundingly, it was discovered that the insertion of cochlear implants could in fact undo cognitive damage even among those who had experienced the greatest cognitive loss.

P. Murali Doraiswamy, M.D., a professor of psychiatry and medicine at Duke University School of Medicine and an expert regarding Alzheimer’s, observed that Mosnier’s study was somewhat flawed but that the essential findings were valid and of huge importance, adding that the positive effects of the cochlear implants combined with the follow-up treatments were more than twice as effective as the FDA-approved drugs available at that time. The most startling take-away, then, is that dementia may not be inevitable.

To make the most of these developments, family and friends should urge those they care about who exhibit a hearing problem (or loss of any of the senses – smell, taste, or sight) to make that doctor appointment and, after the results come in, check your options. They’re only getting better.

0 Comments

  1. Taking into consideration that about 1 in 3 people between the ages of 65-74 suffer from some sort of hearing loss, I think it’s quite frightening, that there is a link between hearing loss and dementia… Not to mention that a lot of these people will end up suffering from depression and loneliness. But at least the FDA has expanded their list of approved hearing aids.

    Thanks for this information.

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