If you suffer from some form of hearing loss, do you ever notice that listening to people talk is work, and that you need 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 tuned and adjusted correctly, and then become accustomed to wearing them.

This frequent sensation may affect more than your hearing; it might also influence your cognitive abilities and your memory. In the latest studies, scientists have discovered that hearing loss significantly raises your chances of contracting dementia and Alzheimer’s.

A 16-year study of this connection conducted by the Johns Hopkins School of Medicine involved 639 people between the ages of 36 and 90. The data showed that 58 study participants – 9% – had developed dementia and 37 – 6% of the total – had developed Alzheimer’s. On top of that, the more significant their degree of hearing impairment, the higher was the chance of developing dementia; for every 10 decibels of hearing loss, the likelihood of dementia went up 20%.

A different 16-year study with 1,984 participants revealed a very similar relationship between dementia and hearing loss, but also found noticeable degradation in cognitive abilities in the hearing-impaired. Compared to individuals with normal hearing, those with hearing loss developed memory loss 40 percent faster. In each of the two studies, a far more depressing finding was that this association was not reduced by wearing hearing aids.

Researchers have suggested several hypotheses to explain the connection between loss of hearing and loss of cognitive capabilities. One explanation is associated with the question at the start of this article, and has been termed cognitive overload. The cognitive overload hypothesis suggests that the hearing-impaired individual expends so much brain power working to hear, that the brain is tired and has a reduced capacity to understand and absorb verbal information. The resulting lack of comprehension may cause social isolation, a factor that has been demonstrated in other studies to lead to dementia. A second theory is that neither hearing loss nor dementia is the cause of the other, but that both are caused by an unknown mechanism that could be environmental, vascular or genetic.

While the person with hearing impairment probably finds these study results depressing, there is a good side with useful lessons to be extracted from them.For those who wear hearing aids, it’s important to have your aids re-fitted and adjusted on a consistent basis. You don’t want to make you brain work harder than it needs to work in order to hear. The less you strain to hear, the more cognitive power your brain has in reserve to understand what is said, and remember it too. Also, if the two symptoms are connected, early detection of hearing impairment might at some point lead to interventions that could avoid dementia.