Problems with External Parts on Cochlear Implants
The National Institutes of Health says almost 220,000 people worldwide with profound deafness or severe hearing impairment have received cochlear implants, about one-third of them in the United States, where two-fifths of the recipients are children.
In conventional cochlear implant, there are three main parts that are worn externally on the head behind the ear: a microphone to pick up sound, a speech processor and a radio transmitter coil. Implanted under the skin behind the ear are a receiver and stimulator to convert the sound signals into electric impulses, which then go through a cable to between four and 16 electrodes that wind through the cochlea of the inner ear and stimulate auditory nerves so the patient can hear.
"It's a disadvantage having all these things attached to the outside" of the head, Young says. "Imagine a child wearing a microphone behind the ear. It causes problems for a lot of activities. Swimming is the main issue. And it's not convenient to wear these things if they have to wear a helmet."
Young adds that "for adults, it's social perception. Wearing this thing indicates you are somewhat handicapped and that actually prevents quite a percentage of candidates from getting the implant. They worry about the negative image."
As for reliability, "if you have wires connected from the microphone to the coil, those wires can break," he says.
How Sound Moves in Normal Ears, Cochlear Implants and the New Device
Sound normally moves into the ear canal and makes the eardrum vibrate. At what is known as the umbo, the eardrum connects to a chain of three tiny bones: the malleus, incus and stapes, also known as the hammer, anvil and stirrup. The bones vibrate. The stapes or stirrup touches the cochlea, the inner ear's fluid-filled chamber. Hair cells (not really hair)
|Contact: Lee Siegel|
University of Utah