Have you started to notice hearing loss? If not, have others told you that you might have a hearing problem? Hearing loss usually comes on so slowly that we don’t notice it until it is quite significant, even though we can benefit from treatment in the form of hearing aids long before our lives become unmanageable as a result of hearing loss.
New research has made the case stronger than ever for treating hearing loss as soon as a hearing test indicates that hearing aids would be beneficial.
Research from Johns Hopkins University has revealed that untreated hearing loss dramatically increases the statistical risk of developing cognitive decline and Alzheimer’s disease or dementia. The correlation was striking between hearing loss and dementia, with the risk of dementia increasing with the severity of hearing loss:
- Mild Hearing Loss (20–40 dBHL) – 2x as likely
- Moderate Hearing Loss (40–60 dBHL) – 3x as likely
- Severe to Profound Hearing Loss (60 or more dBHL) – 5x as likely
Further research has indicated that treating hearing loss with hearing aids or cochlear implants can not only slow or prevent the onset of cognitive decline, it can even allow people to show a reversal of cognitive decline.
How Does Hearing Loss Contribute to Dementia?
It is still not understood exactly how hearing loss leads to such a dramatically increased risk of developing dementia, though there are several theories. It could be that they each make up part of the story.
Cognitive Load
Anyone who has lived with hearing loss can tell you that it increases fatigue, and makes it harder to remember what you hear. This is likely because the act of hearing with untreated hearing loss takes more of our brainpower than normal. With normal hearing, our auditory cortex understands incoming sounds like speech, and decodes that speech more or less automatically, shunting it directly into short-term memory.
When we have hearing loss, we use more of our brains to employ context clues and guessing games in order to make sense of what we’re hearing. That not only tires us out but subtracts more of the resources that our brains would use for memory and other conversation-related thinking tasks.
Over time, this extra cognitive load may exhaust the brain in such a substantial way that it starts to lose resilience.
Brain Atrophy
Another common outcome of long-term untreated hearing loss is the atrophy of the auditory cortex. A certain portion of the brain is devoted to decoding the tens of thousands of messages it receives from the ears on a moment-to-moment basis. Every bit of hearing loss essentially takes away a certain number of those messages, leaving the auditory cortex with less work to do. As this happens, the auditory cortex begins to shrink. It’s not that brain cells die, but the gray matter that supports them starts to dissipate.
This can mean that even when a person starts to wear hearing aids, they are unable to understand what they are hearing. They lose the ability to listen. While there is some indication that wearing hearing aids or cochlear implants will help the auditory cortex regain some of its size and function over time, the initial atrophy is also a likely suspect in the increased risk of cognitive decline and dementia.
Social Isolation
Social isolation is common among those with untreated hearing loss. Over time, the effort that it takes to engage socially starts to seem less than worth it, and people start to avoid social engagements altogether.
But interacting with others is one of the most engaging things we can do with our brains. Humans are inherently social creatures -, it’s almost as though it’s what our brains are made for. When we don’t engage as often with others, cognitive decline can be the outcome. Cognitive decline has been recognized as an outcome of social isolation since long before the link was made between cognitive decline and hearing loss.
Hearing Aids Can Help
The good news in all of this is that hearing aids are incredibly effective at reducing the effects of hearing loss on our health and well-being, and research is increasingly showing that they also reduce the statistical likelihood of developing Alzheimer’s disease.
Those who get hearing aids are not only at a reduced risk of dementia but tend to lead happier, more optimistic lives with greater confidence and independence. When asked after one year of wearing them, 95% of people say they’re glad they got hearing aids.
