Discovery Helps Explain How We Hear Whispers

The inner ear. Credit: NIH

Credit:

Researchers have found a tiny mechanism deep inside the ear that likely helps us hear whispers. The finding could eventually help companies design better hearing aids and other devices for restoring hearing.

Scientists probed the cochlea, a part of the inner ear where physical sound is translated into electrical signals for the brain.

Inside this coiled tube, sound waves glide along a thin membrane, known as the basilar membrane, causing hair-like fibers on the membrane to vibrate at different frequencies. Once stimulated, the fibers shoot out electrical pulses that the brain uses to determine the pitch of the sound.

Hovering right above all of this is the tectorial membrane, along which a different kind of sound wave travels, the scientists discovered. This wave—which bounces from side to side—can excite the hair cells and also enhance their sensitivity, which MIT researcher Roozbeh Ghaffari noted, may help explain how we can pick up on sounds that are as quiet as a whisper.

This finding, Ghaffari says, has major implications for our understanding of how hearing works and potentially for hearing devices currently on the market.

“Most hearing aids we have now are terrible in that they just amplify and blast everything,” Ghaffari said. “Our ears are smarter than that and knows tricks that help us distinguish sounds. Having a better model for cochlear mechanics can lead to improved hearing aids and cochlear implants.”

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