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Research into the Connections Between Hearing Loss and Dementia

If you have some type of hearing impairment, do you ever notice that listening to people speak is work, and that you have to try hard to understand what people are saying? This is a sensation that happens even to those wearing hearing aids, because for them to work well you have to have them fitted and tuned properly, and then become accustomed to wearing them.

As if that was not bad enough, it may not be just your hearing that is impacted, but also cognitive functions. Contemporary studies have indicated that there is a solid association between hearing loss and your chance of developing dementia and Alzheimer’s.

One such research study was conducted by the Johns Hopkins School of Medicine on 639 individuals ages 36 to 90 16-year period. The data showed that 58 study participants – 9 percent – had developed dementia and 37 – 6% – had developed Alzheimer’s disease. The degree of hearing loss was positively correlated with the probability of developing either disorder. For every ten decibel further hearing loss, the risk of developing dementia went up by 20%.

A separate research study of 1,984 people, also 16 years long, demonstrated similar results linking dementia and hearing loss. In this second study, researchers also found decline of cognitive functions among the hearing-impaired over the course of the study. They experienced loss of thinking capacity and memory 40% faster than those with normal hearing. An even more startling conclusion in each of the two studies was that the connection between dementia and hearing loss held true even if the participants wore hearing aids.

The link between hearing loss and loss of cognitive functions is an active area of research, but researchers have proposed a few hypotheses to explain the results seen thus far. One of these explanations relates to the question that began this article, about having to work harder to hear; this has been termed cognitive overload. The cognitive overload theory states that the hearing-impaired person expends so much brain energy working to hear, that the brain is tired and has a reduced capacity to comprehend and absorb verbal information. This can bring about social isolation, which has been linked to dementia risk in other research studies. Another theory is that neither dementia nor hearing loss cause the other, but that they’re both linked to an as-yet-undiscovered pathological mechanism – possibly vascular, possibly genetic, possibly environmental – that causes both.

Despite the fact that these study results are a little depressing, there is hope that comes from them. If you wear hearing aids, see your audiologist regularly to keep them fitted, adjusted, and programmed correctly, so that you are not constantly 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. And, if it ends up that hearing loss is an early indicator of dementia, detecting the hearing loss early may allow for early intervention to prevent the development.

This entry was posted on Saturday, June 8th, 2013 at 12:29 am. Both comments and pings are currently closed.