A study by researchers from the Perelman School of Medicine at the University of Pennsylvania in the US shows that declines in hearing ability may accelerate gray mater atrophy in auditory areas of the brain and increase the listening effort necessary for older adults to successfully comprehend speech.
When a sense such as taste, smell, sight or hearing is altered, the brain reorganizes and adjusts. In the case of people with hearing loss, researchers found that the gray matter density of the auditory areas was lower than in people with normal hearing. This suggests a link between hearing ability and brain volume. This means that people with hearing loss have to work harder to understand complex sentences.
"As hearing ability declines with age, interventions such as hearing aids should be considered not only to improve hearing but to preserve the brain," said lead author Jonathan Peelle, PhD, research associate in the Department of Neurology.
“Your hearing ability directly affects how the brain processes sounds, including speech,” says Dr. Peelle. “Preserving your hearing doesn't only protect your ears, but also helps your brain perform at its best.”
Less brain activity
The researchers measured the brain's response to increasingly complex sentences and the cortical brain volume in auditory cortex. Older adults (60-77 years of age) with normal hearing for their age were evaluated to determine whether normal variations in hearing ability impacted the structure or function of the network of areas in the brain supporting speech comprehension.
The studies found that people with hearing loss showed less brain activity on functional MRI scans when listening to complex sentences. People with hearing loss also had less gray matter in the auditory cortex, suggesting that areas of the brain related to auditory processing may show accelerated atrophy when hearing ability declines.
Today, it is commonly known that hearing sensitivity has cascading consequences for the neural processes supporting both perception and cognition.
Although the research was conducted in older adults, the findings also have implications for younger adults, including those concerned about listening to music at loud volumes.
Talk to your physician
The researchers state that people should talk to their physician or an audiologist if they are experiencing any difficulty hearing or understanding speech. Physicians should also monitor hearing in patients as they age.
The research was published in The Journal of Neuroscience.