They differ from hearing aids, which simply amplify sound for people with hearing difficulties. An estimated 2 million Americans are profoundly deaf, unable to participate in normal verbal conversation or hear smoke alarms or use the telephone. Approved by the FDA in 1996, the implant restores hearing by bypassing damaged parts of the auditory system and sending electrical signals directly to the auditory nerve. As with normal hearing, the auditory nerve carries these signals to the brain where they are interpreted as meaningful sound. Manufactured by companies such as the Cochlear Corporation of Framingham, MA, which produces the Nucleus implant and Advanced Bionics Corporation of California which markets the Clarion implant, the device consists of both surgically implanted and externally worn components.
Sound waves enter the system through a microphone located in the headpiece.
The sound is sent to the speech processor via a thin cable, which connects the headpiece to the speech processor. The processor, a powerful mini computer, converts the sound into a special signal and, once processed, the signal is sent back up the cable to the headpiece where it is transmitted through the skin via radio waves to the implant. The implant receives the signal and delivers it to the electrode array positioned within the cochlea where it stimulates nerve endings and causes electrical impulses to be delivered to the brain where they are interpreted as sound. The impact the implant has had on Victoria s life has been great. It has improved her communication skills to the point that her parents have decided to move her from a school for the deaf to a mainstream school.