Overview of Cochlear Implants

Cochlear Devices
Read more about the type of cochlear implants used at University Hospital.
Internet Resources
A cochlear implant is an electronic device that is surgically implanted into the inner ear and directly stimulates the nerve for hearing. A cochlear implant is not the same thing as a hearing aid. Hearing aids amplify sound, whereas a cochlear implant sends sound directly to the wearer's auditory nerve.
What is a Cochlear Implant
Cochlear implants are electronic devices consisting of:
Sound Processor: Captures sounds and converts them into digital signals. The processor then sends the signals to the internal device.
Coil/Cable Unit: Connects the sound processor to the implant underneath the skin. It helps transmit the electric impulses that enable you to hear.
Cochlear implant sound processor

Sound processor

with cable unit

Cochlear implant internal device

Internal Device

Internal Device: The electrode array is the main element of the implant. It is surgically implanted under the skin and into the cochlea of the ear. Electrodes stimulate the hearing nerve, bypassing damaged hair cells, and the brain perceives the signals so you hear sounds.
How it Works
In a normal ear, sounds are transmitted through the air, causing the eardrum and then the ossicles (middle ear bones) to vibrate. This sends a vibratory wave into the cochlea (inner ear). These waves are then converted by the cochlea into electrical signals, which are sent along the auditory nerve to the brain.
A hearing-impaired person does not have a functioning inner ear. A cochlear implant attempts to replace the function of the inner ear by transforming mechanical energy (sound) into electrical energy, which can then be used to stimulate the cochlear nerve (the nerve for hearing), sending "sound" signals to the brain.
Even with a cochlear implant, the user will still have a hearing loss. The cochlear implant may enable the patient to hear sounds but not understand them. A cochlear implant, like a hearing aid, will be most helpful in a quiet environment. Noisy situations will always make hearing and listening more difficult.