Cognitive Decline and Untreated Hearing Loss — Is There a Link?

September 24th, 2014 by Sharon Macner, Au.D.


hearing loss and cognitive decline

Why live with untreated hearing loss?

As a doctor of audiology with 21 years of experience, naturally I would have an interest in the effects that hearing loss has on one’s ability to effectively communicate with family, friends, and coworkers. But what I find even more intriguing is why a person chooses to live with hearing difficulties rather than seek treatment for it. Currently only 3 in 10 persons with hearing difficulties seek treatment for their hearing loss, and even more astonishing is the fact that it takes the average person with hearing loss a whopping seven years to seek that treatment!

What finally triggers action?

Common responses from my patients go something like this: “It (my hearing) finally got so bad…It came to a point where I just couldn’t understand conversation. I have to do something about it.” Or, “I finally missed something really important because I didn’t hear it. The time has come to do something.” Additionally, I’ve had many wives in my office accompanying their husband, reporting: “I can’t take it anymore. He stands there in a group conversation and doesn’t participate. He doesn’t say anything… he doesn’t know what it being said to him. He misses what our friends are saying to him, or he just nods his head. I’m embarrassed.”

Clinically, I am aware of the top two reasons why a person chooses to ignore their hearing problem. Reason #1: My hearing isn’t bad enough. Reason #2: I can get along without hearing instruments. Actually, a number of years ago, we audiologists would say, “When you are ready to do something about your hearing loss, then it is time to get a hearing aid.” Today, however, the research is clarifying why one should seek amplification for hearing loss much earlier than we previously recommended. What follows is a summary of just three studies which identify cognitive decline with untreated hearing loss. And, just to be clear, “untreated” means not correcting the hearing deficit, either medically or with the use of a hearing aid.

Recent research findings

Let’s look at some recent research findings on untreated hearing loss and cognitive function. In 2011 Johns Hopkins University published a study in the Archives of Neurology  which demonstrated the direct correlation between the participants’ degree of hearing loss and their risk of later developing dementia or Alzheimers disease. Their conclusions were fascinating, and, as I reflected on my patients over the years, I realized that the findings are not surprising. Some of the study conclusions are:

• For each 10 decibel loss of hearing, the participant’s risk of dementia rose about 20 percent;

• Participants with hearing loss at the beginning of the study were significantly more likely to develop dementia by the end. In fact, participants with mild, moderate and severe degrees of hearing loss had two times, three times, and five times, respectively, the increased risk of developing dementia; and,

• Seniors with hearing loss were significantly more likely to develop dementia over time than those who retained their hearing.

In summary, the authors conclude that the increased incidence of dementia in the hearing impaired subjects is possibly due to the strain of deciding sounds over the years which may overwhelm the brain.

In 2005, researchers at Brandeis University published a study in Current Directions in Psychological Science  which concluded that older adults with mild to moderate hearing loss must expend so much energy on hearing accurately that their ability to remember spoken language suffers as a result. I use the following example with my patients: Your brain strives to operate effectively and efficiently. When the auditory centers have full access to sound, information is transmitted effectively across the brain’s networks, which allows the brain operate like, let’s say, a Ferrari. However, when one has untreated hearing loss, the auditory signal going up to the brain is incomplete. Consequently the brain is drained of valuable resources in its effort to perform the same listening task. The brain operates more, shall we say, like a 1973 Pacer.

Additionally, in 2011 researchers at the University of Pennsylvania published a study in the Journal of Neuroscience  on the effects of hearing loss on speech comprehension. Their findings were also not surprising:

• Those subjects with untreated hearing loss had less brain activity on (f)MRI scans when listening to complex sentences; and,

• Those subjects also had less gray matter (think: brain networks) in the auditory cortex, suggesting that in certain parts of the brain related to the understanding of speech, atrophy may occur more rapidly when hearing diminishes.

This study makes a strong case for hearing technology, though the decreased speech comprehension ability is likely a result from a convergence of things happening in the brain of the hearing impaired person, including the effects of decreased social interactions of the hearing impaired person. As well, the study emphasizes that cardiovascular fitness is also important in aiding brain health.

“Is there anything I can do to prevent hearing loss?”

Yes! While the influence of genetics can’t be controlled, one can control some of the variables which cause hearing loss. Let’s start with excessive noise exposure. Noise induced hearing loss is common — quite common, in fact, here in the North Country. I see patients every day who live the effects of noise induced hearing loss. While some of these patients have grown older and wiser and now recognize the importance of using hearing protection, others have still not embraced this habit.  Exposing your hearing to dangerously loud sounds at any age will irreversibly damage your hearing. Examples of dangerous noise sources include farming equipment, heavy equipment, firearms, riding and push mowers, snowblowers, woodworking  and construction equipment, chainsaws, and even heavy-duty wet/dry vacuums. When using these items, one needs to use hearing protection. Always. Hearing protection comes in a variety of forms, and it doesn’t matter for most of the above noise sources which form you use, rather that you use some form of hearing protection, whether it is foam plugs, muffs, or custom earplugs. Hunters do well with shooting plugs designed especially for the sport.

Diet and exercise also influence one’s susceptibility to hearing loss. Eating a diet rich in antioxidants — such as vitamins C and E, magnesium, and lycopene — may help to preserve hearing. This shouldn’t be surprising, as overall vascular health includes the auditory mechanisms as well.

So what is the take-home message?

Seek help for your hearing loss sooner rather than later, preferably when the hearing loss is only mildly impaired. Vigilantly protect your hearing from damaging noise sources. Take action to improve your cardiovascular health. Eat a healthy diet. Take steps other than early treatment of hearing loss to reduce your risk of dementia, including reducing chronic stress, anxiety, and depression. Continually engage in new challenging tasks. Talk with an audiologist about hearing treatment options. Remember, untreated hearing loss affects more than just the affected individual.

Sharon Macner, Au.D.

About Sharon Macner, Au.D.

Dr. Macner of Champlain Valley Audiology, Plattsburgh, NY is licensed as an audiologist by the New York State Department of Education and is also licensed as a Hearing Aid Dispenser by the New York State Department of State. She maintains certification by the American Speech-Language-Hearing Association and maintain fellowship with the American Academy of Audiology.