For the 48 million people in the United States with hearing loss, picking out sounds from noisy environments is a challenge. Research from Massachusetts Eye and Ear, Harvard Medical School, and Harvard University finds that it is possible for people to train their ear—and their brain—to focus on signals in the noise. The findings open the possibility for new treatment options for the hearing impaired or people with other sensory processing issues.
The study’s subjects were mice and adult humans. Some of the humans and some mice played a game that the researchers created. The ‘audiogame’ trained the players to discriminate changes in the loudness of a tone played amidst a moderate level of background noise. Players received instant auditory feedback, which helped them hone in on the target sound. The rest of the humans and the mice were the control group—they listened to sounds but did not play the game. The researchers recorded the electrical activity of neurons in auditory-processing regions of the mice’s cerebral cortex.
After the humans played the audiogame every day for a month, their ability to understand speech in a noisy environment improved. The control group, which did not play the game, did not exhibit a comparable improvement. “Over the course of the training, both species learned adaptive search strategies that allowed them to more efficiently convert noisy, dynamic audio cues into actionable information for finding the target,” stated Daniel Polley, Ph.D., director of the Massachusetts Eye and Ear’s Amelia Peabody Neural Plasticity Unit and assistant professor of ontology and laryngology at Harvard Medical School.
The mice’s brains changed because of the training. Their neurons became sensitive to faint sounds and displayed an increased resistance to noise suppression, which is the ability to encode faint sounds even when there is a lot of background noise.
These findings demonstrate that brain-training exercises can be successful. The results could help researchers develop new therapies for people who are not well-served by traditional sensory rehabilitation strategies.
This research is published in the journal PNAS’ Online Early Edition.
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