What is Cochlear Implant surgery?A cochlear implant device is basically composed of some external and internal parts that allow it to transfer outer noise into the auditory nerve system. The device is composed of these external parts:
- Microphone – One, or more, microphones on the outer shell receive the sounds from the environment.
- Speech Processor – This component functions by filtering background noise from audible speech and bifurcates the audible speech into electrical signals that are then sent to transmitter through a thin cable.
- Transmitter – This is a magnetic coil assisted component situated behind the external part of the ear which uses electromagnetic induction to send the sound signal through the skin and into the internal receiver.
- Receiver & Simulator – It is attached to a bone inside the ear (beneath the skin) and converts the sound signals received from the transmitter into the array of electrodes by converting them into electrical impulses.
- Electrode array – A collective 22 electrodes are arranged in the cochlea of the ear that send the electric impulses to the nerves in the scala tympani and eventually to the brain through the auditory nerve system.
This device is surgically implanted using either general, or local, anesthesia. The surgery involves clearing a small area of the scalp behind the ear by shaving the hair. An incision is made in that area and a hole is made in the mastoid bone behind the ear. This hole is used to fit the external part (simulator/receiver) of the device while the electrode array is fixed inside the cochlea (inner ear).
The implant is activated after a period of around 1-4 weeks by connecting a sound processor to the internal device using a magnet.
The cochlear implant surgical procedure will usually be followed by a speech and auditory therapy regimen depending on the age and severity of the hearing disability, which varies from person to person.