Amplified Sound in the Ear

Researchers at St. Jude Children's Research Hospital say they have found a major clue as to how a genetic mutation or a drug overdose can cause hearing loss. They’ve found an electrically powered amplification mechanism in the cochlea of the ear and say it's a critical part of hearing. There are hair cells inside the cochlea and some hair cells that are outside the cochlea. While the inner cells are passive, the outer cells amplify the sound as it changes into an electrical signal that goes to the brain. If that amplification doesn’t happen, they say the sound waves are severely diminished. Details of their findings are in the May 8 issue of the journal Neuron.