Cochlear implant
A cochlear implant (CI) is an electronic device that is inserted by surgery into a part of the ear called cochlea. Persons who are having difficulty in hearing or are completely deaf use the device to help them hear better. Not all parts of the cochlear implants are inside the ear. They have a microphone and some electronics that are usually placed behind the ear. These electronics send signals to the device implanted in the ear to make hearing possible.
When someone's inner ear hair cells are damages, the conversion of sound vibrations to electrical signals sent to the brain for interpretation gets damaged. Cochlear implants fix this problem by having a microphone of sorts and a speech processor outside of the ear that helps capturing sounds and then processing them. Once the sounds are processed, they are transmitted to something called an internal receiver implanted within the skull on someone that has had the operation for a cochlear implant. The receiver sends signals to electrodes that are manually placed within the cochlea which is the snail-like part in the inner ear. The electrodes stimulate the auditory nerve fibers then send signals to the brain to translate the electrodes into sound.
Most cochlear implants have the following parts. They are divided into external parts which can be seen outside and internal parts which are implanted:
External change
- one or more microphones that pick up sound from the environment
- a speech processor which separates sounds from noise
- a transmitter that sends power and the processed sound signals across the skin to the internal device by electromagnetic induction,
Internal change
- a receiver/stimulator, which receives signals from the speech processor and turns them into electric impulses.
- an electrode inserted in the cochlea
Implanting the device requires proper care and skill. The person on which the device will be implanted will be anesthetized. There are risks, a person may experience mastoiditis or otitis media, the facial nerve or chorda tympani maybe damaged and the implanted device could shift. Wound infections may also occur. After the implant, people may become dizzy and have problems balancing for a few months.
The total cost of a cochlear implant in the United States was about $100,000 in 2017. Health insurance sometimes pays for all or part of the cost of cochlear implants. The national health insurance schemes in the United Kingdom, Australia, Ireland, Spain, and Israel pay fully for the costs of cochlear implants. The Ministry of Health in New Zealand pays the for the new cochlear implant depending on the cause of deafness.