For people reading this who have suffered some type of hearing impairment, do you ever find yourself needing to work very hard to understand what’s being said to you or around you? This experience of having to work to understand people is common even among people who wear hearing aids, because they need to be fitted and tuned properly to work right, and people need to become used to wearing them.

Regrettably, the fallout of this phenomenon might not be restricted to hearing loss; it might also be linked with loss of cognitive function. In recent studies, scientists have found that hearing loss significantly increases your chances of contracting dementia and Alzheimer’s.

A 16-year study of this connection from the Johns Hopkins School of Medicine included 639 participants between the ages of 36 and 90. The data indicated that 58 study volunteers – 9% of the total – had developed dementia and 37 – 6 percent of the total – had developed Alzheimer’s disease. The level 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%.

In a related research study, surveying 1,984 participants, scientists found a similar relationship between dementia and hearing loss, but they also found that the hearing-impaired suffered noticeable decreases in their cognitive functions. In comparison to individuals with normal hearing, those with hearing loss developed memory loss 40 percent faster. A far more startling conclusion in each of the two studies was that the connection between hearing loss and dementia held true even if the individuals used hearing aids.

Various hypotheses have been proposed to explain this apparent connection between hearing loss and loss of cognitive ability. One of these explanations is related to the question that started this article, about having to work harder to hear; this has been called cognitive overload. Some researchers think that if you are hearing-impaired, your brain tires itself out so much just trying to hear that it has a diminished capacity to understand what is being said. The resulting lack of comprehension can cause social isolation, a factor that has been shown in other studies to cause dementia. A different line of thought, hypothesizes that dementia and hearing are not causally related to each other at all. Instead the theory states that they are each the consequence of a third mechanism. This unknown disorder could be vascular, environmental or genetic in nature.

However dismal these study results may seem, there are things to be learned from them. If you use hearing aids, see your audiologist on a regular basis to keep them fitted, tuned, and programmed correctly, so that you’re not constantly straining to hear. The less you have to strain, the more cognitive capacity your brain has in reserve to comprehend what is said, and remember it. Also, if hearing loss is linked to dementia, knowing this may lead to interventional techniques that can delay its development.