Introduction to Cochlear Implant
Cochlear Implant is a small artificial hearing device which is designed to produce hearing sensation by electrical stimulation of nerves inside the inner ear. Also known as Bionic Ear, the implant comprises of two parts: an external portion that sits behind the ear and the internal portion which is surgically planted under the skin. This surgery is of great help to those with impaired hearing.

How Does the Implant Work?
Essentially, an implant has four major parts: a microphone, which picks up sounds and amplifies them; a speech processor, which processes and arranges the sounds; a transmitter, which receives signals from the processor and converts them to electrical impulses; and an electrode array, which collects the impulses and sends them to different regions of the auditory nerve.

It is important to note that a cochlear implant does not restore normal hearing. Instead, it provides a deaf person a useful representation of sounds in the environment to help him or her understand them. The Bionic Ear can help young children who are to acquire speech, language and social skills. Most adults who have lost all or most of their hearing can also benefit from the cochlear implants.

Procedure
The implantation surgery lasts about 2-3 hours and is performed under general anesthesia. The electrode array is fitted into the cochlea while the receiver or stimulator is secured to the skull. The success of operation is tested by checking the functionality of the processor and taking an X-ray to ensure that the device is positioned correctly. Normally, a patient has to stay in the hospital for not more than 2 nights. The patients can resume work as soon as they feel well enough. This is usually within a week.

Follow-Up and Rehabilitation
Rehabilitation is essential for those who have undergone cochlear implants and can be imparted at their hospital and auditory rehabilitation centers. The patient needs to know learning and relearning techniques. Hearing through cochlear implant is very different from normal hearing or hearing through hearing aids. While hearing aids amplify sounds to be heard by damaged ears, the cochlear implants directly stimulate the auditory nerve. The auditory nerve then sends signals to brain which recognizes them as sounds. Over time, the patients learns to hear and enjoy conversations, environmental sounds and music.

Dr Ameet Kishore