Hearing loss has long been linked with an increased risk of cognitive decline. According to researchers at the University of Colorado at Boulder, this is not the only thing we should be worried about. They found that a person’s ability to process and make sense of sound also declines as their ability to hear decreases.
Seeking help for your untreated hearing loss has never been more important.
Cross-Modal Recruitment
Anu Sharma is a professor in the University of Colorado’s Department of Speech, Language and Hearing Sciences and the lead researcher on this study. She and her colleagues recruited patients between the ages of 37 and 68 with no diagnosis of hearing loss to undergo hearing tests and brain exams. While none of the participants were actively being treated, some did suspect they may have mild hearing loss.
The participants completed hearing tests and other tests using visual stimuli. Electroencephalograms monitored their brains while they were completing the tests. The results revealed that seeing images stimulated both the brain’s visual and auditory cortex.
This means that the part of the brain that was previously only responsible for processing sound was now processing visual information. This occurrence is known as cross-modal recruitment.
Sharma explains, “because you rely more on this other sense, what happens is the auditory cortex then gets repurposed for visual processing.”
Cross modal recruitment occurs because of neuroplasticity – the brain’s ability to reorganize itself. While normally seen in children with rapidly developing brains, it can continue on through adulthood.
If the brain does not need to assign as much space to processing sound, it will reallocate some of that space to other senses.
Downside to Neuroplasticity
Cross-modal recruitment can happen in other parts of the brain, not just in the auditory cortex. One area of concern is in the prefrontal cortex, the part of the brain responsible for higher-level thinking and executive function. According to Sharma, “If [the prefrontal cortex] has been recruited just to listen, the issue becomes: Is it going to be available for encoding what you’ve heard into long-term memory, for comprehending and responding, for all the things we have to do after we listen?”
If you wait too long to seek treatment for your hearing loss, you may have a harder time processing sounds once you can hear them again. Even with hearing aids.
Reversible Brain Changes
Neuroplasticity can be reversed, according to new research Sharna is working on. In her most recent study, she took a group of adults with mild to moderate hearing loss and performed a number of tests on cognition, executive function, visual and auditory working memory and depression. The participants were then given top-of-the-line hearing aids, expertly programmed to fit their exact degree of loss.
After wearing the hearing aids for six months, the initial tests were repeated. “We found that the cross-modal plasticity reversed, which was exciting,” Sharma says. “But even more exciting was that they improved in most of their cognitive scores. The only one they didn’t improve on was auditory working memory, but they improved significantly on … executive function, processing speed, visual working memory, all of that.”
The take-away from Sharma’s research is that it is important to act fast; the sooner you seek treatment for your hearing loss, the less time your brain has to change.
To learn more about treating your hearing loss with hearing aids or to schedule an appointment with an expert, contact Hearing Systems today.