Figuring Out the Links Between Hearing Loss and Dementia

Do you have hearing difficulties? If yes, do you sometimes find that it seems like work just to understand what the people around you are saying? This is a phenomenon that happens even to those wearing hearing aids, because for them to perform well you have to have them fitted and tuned properly, and then become accustomed to wearing them.

This frequent sensation may impact more than your ability to hear; it may also influence your memory and your cognitive abilities. In newly released studies, researchers have discovered that hearing loss significantly increases your chances of developing Alzheimer’s and dementia.

One of these research studies, conducted at Johns Hopkins School of Medicine, studied 639 volunteers ages 36 to 90, for a period of 16 years. The data showed that 58 study volunteers – 9 percent of the total – had developed dementia and 37 – 6 percent – had developed Alzheimer’s. Investigators found that for every 10 decibels of hearing loss, the individuals’ odds of developing dementia increased by 20%; the greater the hearing loss, the greater their risk of dementia.

A different study of 1,984 people, also 16 years long, demonstrated comparable results connecting hearing loss and dementia. In this second study, investigators also found degradation of cognitive functions among the hearing-impaired over the course of the study. The hearing-impaired experienced loss of thinking capacity and memory 40% faster than those with normal hearing. In each of the two studies, a far more dismal finding was that this relationship was not reduced by using hearing aids.

Several hypotheses have been suggested to explain this apparent connection between hearing loss and loss of cognitive performance. One hypothesis is associated with the question at the start of this article, and has been given the name cognitive overload. Some researchers suspect that if you are hearing-impaired, your brain tires itself out so much just trying to hear that it has a reduced capacity to understand what is being said. Sustaining a two-way dialogue requires understanding. An absence of understanding causes interactions to break down and might lead to social isolation. Another idea is that neither hearing loss nor dementia cause the other, but that they are both linked to an as-yet-undiscovered disease mechanism – possibly vascular, possibly genetic, possibly environmental – that causes both.

Despite the fact that these study results are a little dismaying, there is hope that comes from them. If you wear hearing aids, visit your audiologist on a regular basis to keep them fitted, adjusted, and programmed correctly, so that you’re not straining to hear. If you do not have to work so hard to hear, you have greater cognitive capacity to understand what is being said, and remember it. Also, if the two symptoms are connected, early detection of hearing impairment may at some point lead to interventions that could delay dementia.