New research from The Ohio State University has found that young people with subtle hearing loss – the kind they aren’t even aware of – are putting demands on their brains that typically wouldn’t be seen until later in life.

Lee and his collaborators recruited 35 healthy men and women, 18 to 41 years old, and monitored their brain activity while the subjects listened to various sentences. The structure of the sentences varied in difficulty as the researchers wanted the participants’ brains to have to work harder to comprehend some of the messages.

The original study was designed to look just at brain differences when sentence complexity increased using functional magnetic resonance imaging (fMRI). Before the fMRI tests were conducted, the researchers tested participants’ hearing to make sure there weren’t any problems that would interfere with the study. Some of the young people had subtle hearing deficits, but nothing serious enough to exclude them from the research.

However, the research team stumbled upon a surprising discovery. Lee and his colleagues were expecting brain activity in the left hemisphere of the brain, but in subjects with subtle hearing decline, the fMRI results also showed activity in the right frontal cortex.

“This isn’t about the ear – it’s about the brain, the cognitive process, and it shouldn’t be happening until people are at least older than 50,” he said. As part of the natural aging process, humans begin to use more of their right frontal brain to process language. But in healthy young people, the left side is wholly responsible for language comprehension. “Their brains already know that the perception of sound is not what it used to be and the right side starts compensating for the left.”

Content by news.osu.edu

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