What is a Cochlear Implant?

Cochlear implants, introduced 20 years ago, have given 83,000 people the ability to hear human speech; they are worn by people who are either severely hard of hearing or profoundly deaf.

Surgeons drill a hole in the skull, embed a sound receiver, and weave an electrode array into the cochlea. Once the hardware is in place, software engineers take over, upgrading the devices as needed so users can enjoy more complex sounds, like music.

1. The earpiece contains a microphone to receive sound and a processor to convert it to digital information.

2. The information travels up to a headpiece that uses a radio transmitter to relay the digitized sound through the skin.

3. The sound is picked up by an implant in the user’s skull. The headpiece clings magnetically to the implant through the scalp.

4. The implant converts the radio signal into electrical pulses, which travel to an array of 16 or 24 electrodes in the inner ear. The electrodes strobe on and off to stimulate the auditory nerves. In time, the user learns to interpret the signals as sound.

5. Users upgrade their hearing by downloading software to the external processor. Early implant users heard just eight channels (compared to 3,000 for normal hearing). The latest software makes 121 channels possible. Tomorrow?

Source: Wired.com