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A Look at the Relationships Between Hearing Impairment and Reduction in Cognitive Function

If you suffer from some form of hearing impairment, do you ever find that listening to people speak is work, and that you have to try really hard to understand what people say? This is a phenomenon that happens even to people wearing hearing aids, because in order for them to perform well you have to have them fitted and tuned correctly, and then get used to using them.

Regrettably, the repercussions of this sensation may not be restricted to hearing loss; it may also be linked with declines in cognitive abilities. The latest studies have indicated that there is a solid association between hearing loss and your risk of developing dementia and Alzheimer’s.

A 16-year study of this relationship from the Johns Hopkins School of Medicine included 639 participants ages 36 to 90. The data indicated that 58 study volunteers – 9% of the total – had developed dementia and 37 – 6 percent – had developed Alzheimer’s. The degree of hearing loss was positively correlated with the likelihood of developing either condition. For every 10 decibel further hearing loss, the risk of developing dementia went up by 20 percent.

A different research study of 1,984 people, also sixteen years in duration, demonstrated comparable results connecting hearing loss and dementia. In this second study, investigators also found decline of cognitive capabilities among the hearing-impaired over the course of the project. When compared with individuals with normal hearing, those with hearing loss developed memory loss 40% faster. An even more startling finding in both studies was that the link between hearing loss and dementia held true even if the individuals wore hearing aids.

A number of hypotheses have been proposed to explain this seeming connection between hearing loss and loss of cognitive performance. One hypothesis is based on the question at the beginning of this article, and has been given the name cognitive overload. Some researchers think that if you are hearing impaired, your brain exhausts itself just trying to hear that it has a reduced capacity to understand what is being said. The resulting lack of comprehension may cause social isolation, a factor that has been demonstrated in other studies to lead to dementia. Another idea is that neither dementia nor hearing loss cause the other, but that they’re both related to an as-yet-undiscovered disease mechanism – possibly vascular, possibly genetic, possibly environmental – which causes both.

However dismal these study results may sound, there are things to be learned from them. For those of us who wear hearing aids, these results serve as a reminder to see our hearing specialists on a regular basis to keep the hearing aids properly fitted and programmed, so that we aren’t constantly straining to hear. The less work expended in the mechanics of hearing, the more brain power available for comprehension. Also, if hearing loss is related to dementia, knowing this may lead to interventional techniques that can delay its onset.

This entry was posted on Friday, August 22nd, 2014 at 7:24 am. Both comments and pings are currently closed.