PHILADELPHIA—Scientists have found further evidence that there’s truth to the old saying, “Use it or lose it.” A group of researchers from the Perelman School of Medicine at the University of Pennsylvania has reported that when hearing loss causes auditory areas of the brain to be deprived of sound, the brain cells begin to atrophy. And, as a result, people with hearing loss are additionally challenged because brain atrophy increases the effort required of them to comprehend speech.
According to the research, published in the latest edition of The Journal of Neuroscience, the density of the gray matter in the auditory areas was lower in people with decreased hearing ability than in those with normal hearing.
EARLY INTERVENTION CALLED FOR
While hearing loss alone is reason enough to get hearing aids or take other appropriate action, the finding that the loss is also damaging brain function offers another compelling reason to treat the hearing loss.
In an interview with Newswise, a news outlet for the Perelman School, Jonathan Peelle, PhD, lead author of the study and a research associate in the Department of Neurology, said, “As hearing ability declines with age, interventions such as hearing aids should be considered not only to improve hearing but to preserve the brain.” He added, “People hear differently, and those with even moderate hearing loss may have to work harder to understand complex sentences.”
In their studies, the researchers examined the relationship of hearing acuity to the brain. They first measured the brain’s response to increasingly complex sentences and then measured cortical brain volume in the auditory cortex. Older adults (60-77 years of age) with normal hearing for their age were evaluated to determine if normal variations in hearing ability affected the structure or function of the network of areas in the brain supporting speech comprehension.
They found that people with hearing loss showed less brain activity on functional MRI scans when listening to complex sentences. Poorer hearers 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. In general, the findings suggest that hearing sensitivity has cascading consequences for the neural processes supporting both perception and cognition.
While the studies involved older adults, the findings are also relevant to younger people, especially those exposed to loud music or noise. Peelle stated, “Your hearing ability directly affects how the brain processes sounds, including speech. Preserving your hearing doesn’t only protect your ears, but also helps your brain perform at its best.”
The research, which was funded by the National Institutes of Health, sends a message to the medical community about the importance of monitoring hearing in their patients as they age. Patients should also be alert to any difficulty hearing or understanding speech, and talk to their physician or a hearing professional if they observe it.