Do you have hearing difficulties? If so, do you occasionally find that it feels like work just to understand what the people near you are saying? You are not alone. The sense that listening and understanding is tiring work is common among people with hearing impairment – even the ones that wear hearing aids.
As if that wasn’t bad enough, it may not be just your hearing that is affected, but also cognitive functions. The latest research studies have revealed that there is a solid relationship between hearing loss and your odds of contracting Alzheimer’s and dementia.
One particular research study was conducted by the Johns Hopkins School of Medicine on 639 participants between the ages of 36 and 90 16-year period. The data indicated that 58 study volunteers – 9% of the total – had developed dementia and 37 – 6% – had developed Alzheimer’s. Moreover, the more significant their degree of hearing loss, the greater was the chance of developing dementia; for every ten decibels of hearing loss, the likelihood of dementia went up 20%.
A different 16-year study with 1,984 participants found a very similar association between dementia and hearing loss, but also identified noticeable degradation in cognitive abilities in the hearing-impaired. Compared to participants with normal hearing, those with hearing impairment developed memory loss 40% faster. In each of the two studies, an even more dismaying finding was that this association was not lessened by wearing hearing aids.
The connection between loss of hearing and loss of cognitive functions is an active area of research, but scientists have suggested a few hypotheses to explain the results seen thus far. One hypothesis is related to the question at the beginning of this article, and has been given the name cognitive overload. The cognitive overload theory states that the hearing-impaired individual expends so much brain power working to hear, that the brain is tired and has a diminished capacity to understand and absorb verbal information. The ensuing lack of comprehension can cause social isolation, a factor that has been demonstrated in other research studies to cause dementia. Another idea is that neither hearing loss nor dementia cause the other, but that they’re each linked to an as-yet-undiscovered disease mechanism – possibly vascular, possibly genetic, possibly environmental – which causes both.
However dismal these study results may seem, there are lessons to be learned from them. For those who use hearing aids, it’s essential to have your aids re-fitted and re-programmed on a consistent basis. You don’t want to make you brain work harder than it needs to work in order to hear. If you don’t have to work as hard to hear, you have greater cognitive capacity to understand what is being said, and remember it. Also, if the 2 conditions are connected, early detection of hearing impairment might eventually lead to interventions that could prevent dementia.