Examining the Links Between Hearing Loss and Dementia

Do you have hearing problems? If so, do you occasionally find that it feels like work just to understand what the people near you are saying? You are not the only one. The sense that listening and understanding is taxing work is common among people with hearing loss – even the ones that wear hearing aids.

As if that was not bad news enough, it might not be just your ability to hear that is affected, but also cognitive abilities. Hearing impairment greatly increases your odds of contracting Alzheimer’s or dementia according to the latest research studies.

One of these research studies, from the Johns Hopkins School of Medicine, analyzed 639 participants ages 36 to 90, for a period of 16 years. The data showed that 58 study participants – 9 percent – had developed dementia and 37 – 6 percent of the total – had developed Alzheimer’s. They found that for every 10 decibels of hearing loss, the individuals’ odds of developing dementia went up by 20 percent; the more significant the degree of hearing loss, the greater their risk of dementia.

A separate study of 1,984 people, demonstrated comparable results connecting hearing loss and dementia. In this second study, investigators also found degradation of cognitive capabilities among the hearing-impaired over the course of the data gathering. In comparison to participants with normal hearing, those with hearing loss developed memory loss 40 percent faster. An even more surprising conclusion in both studies was that the link between hearing loss and dementia held true even if the individuals used hearing aids.

The connection between hearing loss and loss of cognitive functions is an active area of research, but scientists have proposed a few theories to explain the results seen to date. Scientists have coined the term cognitive overload in conjunction with one particular hypothesis. The theory is that among the hearing-impaired, the brain tires itself out so much trying to hear that it can’t focus on the meaning of the sounds that it is hearing. Maintaining a two-way conversation requires understanding. A lack of understanding causes conversations to break down and may result in social isolation. Another idea is that neither dementia nor hearing loss cause the other, but that they are both related to an as-yet-undiscovered pathological mechanism – possibly vascular, possibly genetic, possibly environmental – that causes both.

Even though these study outcomes are a little dismaying, there is hope that comes from them. For people who use hearing aids, it’s crucial that you have your hearing aids re-fitted and re-programmed on a consistent basis. You shouldn’t make you brain work harder than it needs to work in order to hear. If you do not have to work as hard to hear, you have greater cognitive power to understand what is being said, and remember it. Also, if the two symptoms are linked, early detection of hearing impairment might eventually lead to interventions that could avoid dementia.