Thumping music at a concert, screeching sirens in the street, car alarms – the list of loud and painful sounds that can affect hearing goes on and on. Now scientists at Johns Hopkins believe they have uncovered a mechanism in the inner ear that acts as an internal volume control, adjusting the noise to protect against permanent damage.
Making sense of the study
“There’s some uncertainty in the field about what this sound-limiting system is used for,” says Paul Fuchs, Ph.D., an author on the paper and professor of otolaryngology-head and neck surgery and co-director of the Center for Sensory Biology at the Institute for Basic Biomedical Sciences at Johns Hopkins. “Now we’ve definitively shown that this system functions in part to prevent acoustic trauma.”
Fuchs believes the brain sends a signal to a special sensor in the ear and tells it to “turn down” the noise. They tested this theory in mice and found results that back it up. The team subjected mice to soft sounds as well as loud, concert like, sounds and found the ear makes adjustments itself.
The team blasted 100-decibel sound at mice and again measured their ability to hear. “One hundred decibels, for me, is painfully loud, and conversation is impossible,” says Fuchs. “But sound levels in night clubs or rock concerts can be that high, and extended exposure to sound at that volume can cause hearing loss.”
Scientist were able to tweak this sensory nerve in mice to test the theory an believe it could lead researchers to a better understanding of hearing problems.
How it could help in years to come
“So far, there is little or no specific pharmacology of hearing. We’re still learning how the inner ear works. The encouraging news that cold lead to ear-specific drugs in the future.”
Until then, Fuchs suggests limiting time spent at rock concerts, and wearing earplugs, to protect your hearing.
