Can Hearing Aids Prevent Dementia?

As the prevalence of hearing loss in the “boomer” population increases, there is an alarming new risk factor associated with prolonged untreated hearing loss that has been identified: cognitive decline and dementia.

In this post we will look at some of the latest research on this topic and discuss why this is important, especially for the older population

Hearing Loss Is Related To Dementia, But Some Myths Still Abound

There’s an increasing amount of research that shows a relationship between untreated hearing loss and mental problems in the older population. The realization of this relationship all began in nursing care facilities where staff first reported the almost miraculous improvements of elderly residents once they were dispensed hearing aids.

This prompted a series of studies looking at untreated hearing loss and cognitive function in older adults.
Years later, we have a growing body of research that shows a relationship between changes in brain morphology (structure) and cognitive function associated with auditory deprivation. Despite this robust body of research, there are some myths on this topic that need to be addressed.

Myth #1: Hearing Loss Causes Memory Loss

Firstly, it has not been shown in clinical studies that hearing loss in humans directly causes memory loss. As the saying goes, “correlation is not causation.” This means that we haven’t yet proven that a certain amount of hearing loss, maintained for a certain number of years, causes a certain decline in cognitive function in humans.

There are examples of this not being true. One example is the famous deaf and blind author, Helen Keller. Despite a total loss of her primary senses, she was sharp-witted her whole life.

So, you may ask, what is the relationship of hearing loss to cognitive decline?

Research is still being done on this topic. However, the leading assumption is that acquired hearing loss, if left untreated in older adults, can result in a dramatic loss of social function. We call this “activity limitation.” In fact, it has been shown that any disability that leads to activity limitation can result in progressive impairments in mental acuity. This suggests that social function and “activity participation” are the keys to successful aging of the brain.

Why was this not the case with Helen Keller?

Arguably, it is because she adapted to her loss of primary senses early in life. So, as she aged, she did not experience a change in social function associated with loss of sight and hearing as she had already adapted to it. Imagine, if you would, if Helen Keller had lost the ability to read brail with her delicate fingertips. This would have cut her off from reading altogether, which was a very important activity for her. This alone would have likely been detrimental to her successful aging.

Myth #2: Hearing Aids Can Prevent Alzheimer’s Disease

The second common myth is that a person with Alzheimer’s will see a reversal of their decline if they start using hearing aids. It is true that for people who have significant hearing loss, and who have cognitive issues, wearing hearing aids can preserve connection to other people and help them maintain a social life. And we believe this does help slow down the symptoms of Alzheimer’s.

What is most important to consider is that use of hearing aids can delay the onset of diagnosis of Alzheimer’s disease, as well as other aspects of dementia, depression, anxiety, and injury-causing falls among older adults. This is according to a review study published in 2019 (see reference below; Mahmoudi, et al.).

Research Shows A Relationship Between Hearing Loss and Dementia?

An article titled “Hearing Impairment and Incident Dementia and Cognitive Decline in older Adults: The Health ABC Study” was published in the Journal of Gerontology in 2016, which was authored by some of the biggest name researchers in prevalence of hearing loss and its impact in the general population.

This peer reviewed article clearly shows an association of hearing impairment with dementia, decline in memory, perceptual speed, and processing speed.

The study followed 1003 participants for 9 years and found that individuals with moderate/severe hearing impairment, compared to those in the study with normal hearing, had increased risk of dementia.

In conclusion, the researchers found that long-term (at least 9 years) untreated, moderate, or worse, hearing loss is a risk for poor mental health in the older population.

More recently, an article titled “The Longitudinal Relationship Between Hearing Loss and Cognitive Decline” by Nicholas A. Waring and colleagues, reveals that even sub-clinical hearing loss, which is a minimal amount of hearing loss, over a long period of time, is related to cognitive impairments compared to a control group with perfectly normal hearing.

This study was based on the Health, Aging, and Body Composition (Health ABC) Study, which is a longitudinal multi-center cohort of 3,075 participants (42% black and 58% white), 70-79 years old when they were recruited in 1997-1998.

For these participants, hearing and cognitive tests were performed at regular intervals for several years.

These researchers interpreted their results to mean that over the long term, even minimal hearing loss can have an impact on cognitive function, which is made worse with advanced age. Of course, they do go on to say that they have not proven a direct causal relationship, but the evidence is strong that there is some kind of important relationship between these variables worth considering.

These researchers suggest that it’s the primary effect hearing loss has on communication and social function that leads to social isolation that is responsible for the cognitive deficits in their study.

Research Looking At the Relationship Between Hearing Loss and Dementia is Ongoing

As mentioned earlier in this post, just because there is a relationship, or correlation, between two variables, this does not mean that variable A causes variable B.

In the case of untreated hearing loss and cognitive decline, we do know that age is an issue that needs to be accounted for. Not all people age equally as well. So, the impact of untreated hearing loss on a person’s social life is not going to be the same, necessarily, for a different person.

But, if we look at the big picture, we can see that having untreated hearing loss for a long period of time, especially in older people, can lead to a loss of social life and that, in turn, can lead to cognitive decline (or at least it can exacerbate it).

Future research needs to be done that incorporates the gold standard of randomized controlled trials. This kind of research is very difficult to perform in large groups, but it can be done, nonetheless. This kind of study would look at the effects of untreated hearing loss in one group, compared to another group that was dispensed hearing aids, and perhaps a third group with no hearing loss at all.

These kinds of randomized controlled trials are underway at select research centers around the world, but the results are not quite “all in”. So, we may have to wait a couple of years before we really get a true grip on this issue.

Why We Should Care If Hearing Loss Is Related to Dementia

The real reason this is important is that it shows yet another benefit for people who have hearing loss to wear hearing aids.

We have known for a long time that hearing loss can greatly impair normal speech development and academic performance in children. But now we have new evidence that shows that untreated hearing loss in older people is a risk factor that might affect cognitive function and memory.

Perhaps we can say that hearing aids can not only help a person improve their marriage, their participation in social activities, and even help them stay employed- they can help a person maintain a healthy brain!

References

Deal JA, Betz J, Yaffe K, et al. (2017) Hearing Impairment and Incident Dementia and Cognitive Decline in Older Adults: The Health ABC Study. The Journals of Gerontology Series A, Biological Sciences and Medical Sciences, 72: 703-709. DOI: 10.1093/gerona/glw069

Waring, Nicholas A. BS; Chern, Alexander MD; Golub, Justin S. MD, MS. (2023) The Longitudinal Relationship Between Hearing Loss and Cognitive Decline. The Hearing Journal, 76(03): 26,27,28. DOI: 10.1097/01.HJ.0000922284.78796.fe

Mahmoudi, E, Basu T, Langa K, et al., Can Hearing Aids Delay Time to Diagnosis of Dementia, Depression, or Falls in Older Adults? Journal of the American Geriatrics Society, 67: 2362-2369.