The Brain Hears-Cochlear-Implants
The Brain Hears-Cochlear-Implants

The Brain Hears-Cochlear-Implants

Radhika Mohan

"Blindness cuts us off from things, but deafness cuts us off from people," is a moving quote often attributed to the famed 20th-century activist and educator Helen Keller. She also wrote in a 1910 letter: "The problems of deafness are deeper and more complex, if not more important, than those of blindness. Deafness is a much worse misfortune. For it means the loss of the most vital stimulus — the sound of the voice that brings language, sets thoughts astir and keeps us in the intellectual company of man." Helen Keller, who was born in 1880, lost her vision and her hearing when she was 19 months old, from an infection that was probably scarlet fever or meningitis. Like many toddlers at that age, she had some spoken language, which was presumably lost in the trauma of her illness. Given a chance, today, Helen Keller’s parents would have opted for cochlear-implants and auditory verbal therapy that would have enabled her to mainstream into the normal hearing world.


Who would have thought in the olden days that nature’s inspiration by a seashell and a blade of wild grass, would have led to one of the greatest inventions on hearing-technology of all times. A cochlear implant is a small, complex electronic device that can help to provide a sense of sound to a person who is profoundly deaf or severely hard-of-hearing. The implant consists of an external portion that sits behind the ear and a second portion that is surgically placed under the skin. An implant has the following parts:

  • A microphone, which picks up sound from the environment.
  • A speech processor, which selects and arranges sounds picked up by the microphone.
  • A transmitter and receiver/stimulator, which receive signals from the speech processor and convert them into electric impulses.
  • An electrode array, which is a group of electrodes that collects the impulses from the stimulator and sends them to different regions of the auditory nerve.

An implant does not restore normal hearing. Instead, it can give a deaf person a useful representation of sounds in the environment and help him or her to understand speech.

Who can go for an implant?

Changing Candidacy Criteria

Technological advances have brought dramatic changes in candidacy criteria, opening the door for more people with severe and profound hearing losses to choose this option. When the U.S. Food and Drug Administration (FDA) first approved a cochlear implant with a single electrode for adults in 1985 and for children in 1990, only those who were almost completely deaf and could only perceive vibrations with a hearing aid could qualify. Today, children and adults who were not candidates just two years ago may well be considered as candidates. The age of pediatric candidates has dropped from 2 years to as young as 12 months, and eligibility criteria for adults continue to expand. According to the FDA, adults can now be considered candidates if they have severe-to-profound hearing loss and understand less than 50% of sentences spoken to them. They should also have realistic expectations, motivation to learn to hear again, and no medical contraindications to surgery. Greater numbers of prelingually deaf adults, who lost their hearing before acquiring language, are now beginning to consider cochlear implants as a tool to enhance communication. With the help of cochlear-implants, they can hear at greater distances, hear well in presence of back-ground noise as well as be socially active. Unless contraindicated by other health problems, cochlear-implants are definitely a go for geriatric population too.

Cochlear-implants are now opted as a solution for unilateral deafness. There are several studies pinpointing to the fact that cochlear-implants are better option as when compared to a bone-anchored hearing aid or CROS hearing-aid.

Going Bilateral

To experience everyday sounds in stereo, hearing with both ears is important. Bilateral implantation is the ideal solution to provide complete hearing experience. For children, going bilateral leads to a faster speech and language acquisition. In case of post-lingual adults who opt for a cochlear-implant, bilateral implantation is the best solution as it can balance sounds coming from both the sides and can help in having a more relaxed hearing experience.

Auditory-Verbal Therapy/Auditory Training

AVT/AT is specialized training given for cochlear-implant recipients wherein brain is trained to listen to the sounds. Family participation is very important for this.

Lastest Sound Processor

With the ground breaking technology by Cochlear-Kanso processor, one can enjoy the benefits of crisp and clear hearing. It is the smallest processor available. Through, Kanso it is also possible to hear underwater with the help of Aqua+, which is available with the processor. This makes swimming with the processor on, possible for children and adults. Also with complete automatic programs and wireless accessories, hearing through phone, watching TV, listening in classrooms are a lot more easier.

Dance along every tune with sprint, Cochlear has put an end to the struggle to hear.

Don’t think twice Kanso is here, you can fly like a bird or swim like a fish. How to enjoy your life is after all... your wish.’

--Bhagyashree ,Cochlear-Implant Recipient

Thus with latest technological advancements, cochlear-implants open up a new world of hearing for the hearing-impaired population.

Facilities at Amrita Hospital-

With focus on early identification of hearing-loss, Amrita Hospital has well-equipped diagnostic tools for subjective and objective assessment of hearing-loss. Also neonatal screening is made mandatory.

Audiologists who have received specialized training on cochlear-implants and auditory verbal therapy caters to provision of therapeutic and diagnostic services. Also, as a part of Government initiated ADIP (Assistance to Disabled Persons for Purchase/Fitting of Aids/Appliances) scheme program hospital is providing free cochlear-implantation for all children below four years of age.

Radhika Mohan, Lecturer

Department of Speech-Pathology & Audiology

Amrita Institute of Medical Sciences & Research Centre, Kochi, Kerala