What is a cochlear implant?
A cochlear implant is an implanted electronic hearing device, designed to produce useful hearing sensations to a person with severe to profound nerve deafness by electrically stimulating nerves inside the inner ear.
These implants usually consist of 2 main components:
- The externally worn microphone, sound processor and transmitter system.
- The implanted receiver and electrode system, which contains the electronic circuits that receive signals from the external system and send electrical currents to the inner ear.
Currently made devices have a magnet that holds the external system in place next to the implanted internal system. The external system may be worn entirely behind the ear or its parts may be worn in a pocket, belt pouch, or harness.
Who uses cochlear implants
A prime candidate is described as:
- having severe to profoundsensorineural hearing loss in both ears.
- having a functioning auditory nerve
- having lived at least a short amount of time without hearing (approximately 70+ decibel hearing loss, on average)
- having good speech, language, and communication skills, or in the case of infants and young children, having a family willing to work toward speech and language skills with therapy
- not benefiting enough from other kinds of hearing aids, including latest models of high power hearing instruments and FM systems
- having no medical reason to avoid surgery
- living in or desiring to live in the “hearing world”
- having realistic expectations about results
- having the support of family and friends
- having appropriate services set up for post-cochlear implant aural rehabilitation (through a speech language pathologist, deaf educator, or auditory verbal therapist).
What are the Benefits of Cochlear Implants?
- Hearing ranges from near normal ability to understand speech to no hearing benefit at all.
- Adults often benefit immediatelyand continue to improve for about 3 months after the initial tuning sessions. Then, although performance continues to improve, improvements are slower. Cochlear implant users’ performances may continue to improve for several years.
- Children may improve at a slower pace.A lot of training is needed after implantation to help the child use the new ‘hearing’ he or she now experiences.
- Most perceive loud, medium and soft sounds.People report that they can perceive different types of sounds, such as footsteps, slamming of doors, sounds of engines, ringing of the telephone, barking of dogs, whistling of the tea kettle, rustling of leaves, the sound of a light switch being switched on and off, and so on.
- Many understand speech without lip-reading.However, even if this is not possible, using the implant helps lip-reading.
- Many can make telephone callsand understand familiar voices over the telephone. Some good performers can make normal telephone calls and even understand an unfamiliar speaker. However, not all people who have implants are able to use the phone.
- Many can watch TV more easily,especially when they can also see the speaker’s face. However, listening to the radio is often more difficult as there are no visual cues available.
- Some can enjoy music.Some enjoy the sound of certain instruments (piano or guitar, for example) and certain voices. Others do not hear well enough to enjoy music.
How does a cochlear implant work?
A cochlear implant receives sound from the outside environment, processes it, and sends small electric currents near the auditory nerve. These electric currents activate the nerve, which then sends a signal to the brain. The brain learns to recognize this signal and the person experiences this as “hearing”.
The cochlear implant somewhat simulates natural hearing, where sound creates an electric current that stimulates the auditory nerve. However, the result is not the same as normal hearing.