It’s not uncommon for teens and young adults to turn up the volume on their iPods or smartphones or stand near the speakers at a music concert or nightclub to enhance the experience. Even if they have the foresight to realize these choices could be damaging to their hearing, what neither they nor their parents know is this kind of behavior also could be altering their brain function for life.
A recent study in the May 2018 issue of the journal eNeuro found that young adults with subtle hearing loss – a deficit that’s so slight that they’re not even aware of it (they reported they had normal hearing) – are placing demands on their brains that don’t normally occur until later in life.
In the study, researchers used functional magnetic resonance imaging scans to monitor brain activity, while healthy men and women, ages 18 to 41, listened to various sentences that varied in their complexity and the demands required to process and understand them. Before performing the fMRI scans, the researchers tested the participants’ hearing acuity and found that some of them had subtle hearing deficits (but were still clinically in the normal range).
What the researchers found, using fMRI, is that listeners with poorer hearing had activity in the right hemisphere of the brain (specifically, the right frontal cortex), which was surprising because usually the left hemisphere of the brain is completely responsible for regulating speech and language comprehension. And the altered brain function was consistent regardless of how simple or complex the sentence structure was.
On the upside, the brain is an amazingly plastic organ, meaning it has the ability to change and adapt throughout life, explains lead researcher Yune Lee, an assistant professor of chronic brain injury in the department of speech and hearing science at Ohio State University.
As people age, they begin to use more of their right frontal brain to process language, but “we don’t typically see that in younger people,” Lee explains. “That is worrisome because they start using up these resources too early in life. It’s like withdrawing money from a retirement account too early; these resources need to be preserved for later in life.”
The findings are especially significant, says Sarah Sydlowski, audiology director of the Hearing Implant Program at the Cleveland Clinic.
“…hearing involves hearing sound but also processing it and extracting meaning
[in the brain]. Exposure to loud sound can cause subclinical damage to ‘synaptic ribbons’ – essentially the connections between the sensory cells in the inner ear and the hearing nerve. People with this damage suffer from what is being referred to as ‘hidden hearing loss’ because often they will appear to have normal hearing on a standard hearing test, yet they may complain that they have difficulty understanding speech in noisy environments or groups,” Sydlowski explains.The long-range concern is that a growing body of evidence has shown a significant link between hearing loss and dementia. In fact, a review of studies in the June 2018 issue of Maturitas found that hearing impairment at midlife is associated with a 50 percent higher risk of developing dementia later in life.
“If you put all your energy into hearing, you drain cognitive resources that could be used for other things such as memory and attention,” Lee says.
If you suspect that you’re struggling to hear clearly or process what you hear comfortably or accurately, you should get your hearing checked, including your ability to hear and understand speech against background noise. The American Speech-Language-Hearing Association calls for adults to be screened for hearing loss at least every decade through age 50 then every three years after that.
The sooner you detect a hearing problem, the better; that way, you can take steps to address it, whether that means modifying your environment to minimize distractions, adding protection for your hearing, doing auditory training (listening exercises) or considering a hearing device.
The take-home message: Consider these findings more good reasons to turn down the volume on your personal music players and wear earplugs when you go to concerts.
“Take care of your hearing because it’s important for your well-being,” Lee says. “Young people should consider checking their hearing acuity regularly just like they check their cholesterol level and blood pressure.”
Source: U.S. News & World Report