If you suffer from some type 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 are saying? You aren’t the only one. The feeling that listening and understanding is taxing work is typical among individuals with hearing impairment – even those that wear hearing aids.
Sad to say, the consequences of this sensation may not be limited to hearing loss; it may also be connected to loss of cognitive function. Hearing impairment markedly increases your risk of developing dementia or Alzheimer’s according to recent studies.
One such research study was conducted by the Johns Hopkins School of Medicine on 639 individuals between the ages of 36 and 90 16-year period. The scientists found that at the end of the study, 58 of the participants (9%) had developed dementia, and 37 (5.8%) had been diagnosed with Alzheimer’s disease. Researchers found that for every 10 decibels of hearing loss, the individuals’ chances of developing dementia increased by 20 percent; the more significant the hearing loss, the higher their risk of dementia.
Another 16-year study with 1,984 participants found a similar relationship between dementia and hearing loss, but also observed noticeable decline in cognitive abilities in the hearing-impaired. They experienced loss of thinking capacity and memory 40 percent faster than those with normal hearing. A vital, but disturbing, finding in both research studies was that the adverse cognitive effects were not diminished by using hearing aids. The connection between hearing impairment and loss of cognitive functions is an open area of research, but scientists have offered a few hypotheses to explain the results seen thus far. One of these explanations relates to the question that started this article, about needing to work harder to hear; this has been termed cognitive overload. The theory is that among the hearing-impaired, the brain exhausts itself so much working to hear that it can’t concentrate on the meaning of the speech that it is hearing. The resulting lack of understanding may cause social isolation, a factor that has been shown in other research studies to lead to dementia. Another idea is that neither dementia nor hearing loss cause the other, but that they are each related to an as-yet-undiscovered pathological mechanism – possibly vascular, possibly genetic, possibly environmental – which causes both.
However depressing these study results may sound, there are lessons to be learned from them. For those who use hearing aids, it is crucial that you have your aids re-fitted and adjusted on a consistent basis. You shouldn’t make you brain work harder than it has to work in order to hear. The less you strain to hear, the more cognitive capacity your brain has in reserve to comprehend what is said, and remember it too. Also, if loss of hearing is linked to dementia, knowing this may lead to interventional techniques that can postpone its development.