A slow loss of hearing ability is generally viewed as a normal and accepted part of aging. It is an unfortunate reality many of us will face as we get older. About two-thirds of Americans experience some hearing loss by the time they reach their 70s. It is perceived to be so inevitable that many do not seek any treatment or remedy for hearing loss. In fact, less than 15-20 percent of people diagnosed with hearing loss even use hearing aids.
However, research is now increasingly pointing to links between hearing loss and cognitive impairment, from mild difficulties to full dementia. In one 2013 study that followed nearly 2,000 older adults, subjects who began the study with hearing impairment were shown to be 24 percent more likely to experience cognitive decline. This led the researchers to believe that hearing loss accelerated the cognitive decline of these patients.
A new French study published in 2015 also supported a link between hearing loss and more accelerated cognitive decline. However, this study also showed that when older adults with hearing impairment used hearing aids, the rate of cognitive decline was the same as older adults with normal hearing. On the other hand, those who did not use hearing aids demonstrated a more accelerated rate of cognitive decline. This means that using a hearing aid could contribute to reducing the rate of cognitive decline for adults with hearing loss.
This is encouraging news. Scientists are not entirely certain how the conditions are linked, but some possible factors are being explored. It may be that both conditions are influenced by a single common trigger such as high blood pressure, for example. Another possibility is that when an individual has difficulty with hearing, so much of the brain’s effort is expended in trying to understand auditory input that it essentially overloads the brain’s resources, leaving little left for more demanding functions such as creating and storing memories. Yet another theory suggests that hearing loss might be related to changes in brain structure that, in turn, influence cognitive functioning. Areas of the brain that process and interpret sounds can shrink as they become underutilized which might then contribute to overall cognitive impairment.
And last, but not least, one important and obvious factor to consider is the social isolation that is often associated with hearing loss. Individuals with hearing impairment find normal conversation and group social situations difficult and uncomfortable. It is not uncommon for those suffering from hearing loss to avoid challenging social situations which can lead to increasing isolation.
In fact, in that recent French study mentioned earlier, when the researchers controlled for factors such as social isolation and depression, the difference in rates of cognitive decline among all the different subject groups was not significant.
This suggests that it may not be hearing loss itself that is directly influencing rates of cognitive decline, but rather that hearing loss is leading to depression or social isolation which then contributes to impaired cognition. The hearing aids might be improving the users’ moods and social engagement, which may then be leading to improved brain health. It remains unclear at this time whether improved hearing or improved mental health is the key here to reducing the risk of dementia.
In any event, this news should certainly encourage all older adults to make sure their hearing is checked regularly. Doctors are increasingly aware that addressing and correcting hearing loss can be much more effective than currently available drugs to reduce rates of cognitive decline. Although it is still uncertain whether this is due to a direct impact on brain functioning or improved social engagement, addressing and correcting hearing impairment can lead to less isolation, improved mental health and a better overall quality of life. And who wouldn’t want that?