The cochlear implantation (CI) program was started in All India Institute of Medical Sciences in 1996 under the chairmanship of Prof.RC Deka and the first adult patient was successfully operated upon in February 1997. Soon, the department started the Children Program in 1998. Till now (Feb 2020), we have performed more than 1000 cochlear implant surgeries in adults and children. The department has provided support in starting a cochlear implant program in R.R. Hospital, Central Railway Hospital in New Delhi, and also PGIMER in Chandigarh.
What is a cochlear implant?
A cochlear implant is an electronic device that restores partial hearing to the deaf. It is the only treatment option available for patients with bilateral profound sensorineural hearing loss if there is no benefit with hearing aids.
How does a cochlear implant work? A cochlear implant is surgically implanted in the ear and activated by a device worn behind the ear. It converts sound to electrical impulses. These impulses are then transmitted via hearing nerve to the brain. The device bypasses damaged parts of the auditory system (hair cells of the cochlea) and directly stimulates the nerve of hearing, allowing individuals who are profoundly hearing-impaired to perceive sound.
What are the components of Cochlear Implant?
Cochlear implants have two parts - a. External (outside) parts that include a microphone, a speech processor, and a transmitter. b. Internal (surgically implanted) parts - a receiver-stimulating system fixed to the skull bone behind the ear and electrodes which are inserted into the cochlea
The microphone picks up sounds and sends them to the speech processor. The speech processor analyzes and digitizes the sound signals and sends them to a transmitter worn on the side of the head just behind the ear. The transmitter sends the coded signals to an implanted receiver. The receiver in turn delivers them to the array of electrodes that stimulate the fibers of the auditory nerve directly. The auditory nerve transmits this information to the brain where it is interpreted as meaningful sound and thus the implanted person starts learning language and speech communication skills.
Cochlear Implant surgery in AIIMS
An implant team consisting of Otolaryngologist, Audiologist, Radiologist, Pediatric Neurologist, Clinical Psychologist and Speech Therapist does the clinical and other laboratory assessment before planning for surgery. Implant surgery is performed under general anesthesia and lasts from two to three hours. The procedure requires a stay in the hospital for 7 to 10 days.
The postoperative rehabilitation will be done by the rehabilitation team consisting of Otolaryngologist, Audiologist and Speech Therapist. Parents’ participation in the training is of paramount importance and one of the parents has to learn the therapy to train the child at home. When the surgical wound is well healed (usually 3 to 4 weeks after surgery) the cochlear implant is activated (switch-on) and a MAP is created using computer based software. The subsequent mapping sessions are individually tailored as per the progress made by the patient. The short and long term goals are set for listening and then language and speech. The therapist teaches the child to listen to the sound that is received from the cochlear implant and helps them in the developing effective spoken communication, leading to development of language and speech.
When my child/ the patient start hearing and speaking?
Cochlear implants do not restore normal hearing, and benefits vary from one individual to another. The implantees are expected to hear and/or recognize sounds/speech and learn language through the auditory input with the help of a cochlear implant. In children, 4-5 years of intensive training is needed.