A decline in an older adult’s hearing ability may accelerate brain atrophy and increase the necessary effort exerted to comprehend speech, according to a new study in The Journal of Neuroscience from researchers at the Perelman School of Medicine at the University of Pennsylvania.
When one of the five senses is altered, the brain reorganizes and adjusts. In the case of poor hearers, researchers found that the gray matter density of auditory areas was lower in people with decreased hearing ability, suggesting a link between hearing ability and brain volume.
“As hearing ability declines with age, interventions such as hearing aids should be considered not only to improve hearing but to preserve the brain,” researchers said. “People hear differently, and those with even moderate hearing loss may have to work harder to understand complex sentences.”
In a pair of studies, researchers measured the relationship of hearing acuity to the brain, first measuring the brain's response to increasingly complex sentences and then measuring 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. 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, researchers said.