What is Cochlear Implant?



A cochlear implant is an electronic device comprised of 'an implanted part' and 'an external component'. 'The implanted part' is made up of a receiver/stimulator and a filament which can produce a multi-channel electrode array to stimulate the auditory nerve (to be implanted into the cochlear). 'The external component' consists of a transmitting coil, a microphone and a speech processor. Audiologists will programme the speech processor to suit the need of each CI user.

The structure and mechanism of the cochlear implant are more complex than a conventional hearing aid. It brings a greater awareness to a broader range of sounds. Although the cochlear implant cannot restore damaged auditory nerves or hearing, it improves sound reception and speech perception with the sophisticated device and post-operative training.

Q. Who can benefit from a cochlear implant?


When conventional hearing aids cannot help patients with severe to profound sensorineural hearing loss to improve their hearing and communication ability, they may consider the option of cochlear implantation. In general, the shorter the period of hearing loss, the better the outcome will be. This period is especially crucial for children, as infancy is the prime time for developing speech and communication skills. Delay in treatment will hinder rehabilitative training and badly affect surgery outcomes.

General criteria for the cochlear implant :
1. bilateral severe to profound sensorineural hearing loss
2. aged 12 months or above
3. inability to recognize speech through conventional hearing aids or other hearing device
4. no contraindications to implant surgery
5. a strong wish to improve hearing with appropriate understanding and expectations of the results of surgery
6. a high degree of commitment and appropriate expectation of the surgery outcome and rehabilitative training
7. for children, a comprehensive educational facility and programme that emphasize development of their auditory skills

What is the risk of having Cochlear Implants? Will it take a long time to recover?


The 'implanted component' of the cochlear implant is surgically implanted into the bionic ear. The surgery takes two to three hours. Published report proves that cochlear implant surgery is safe in general.

Complications caused by cochlear implant surgery are more or less the same as the other surgeries, for example, anesthetic risk, inflammation, infection and bleeding, etc. Other complications brought about by otological surgeries are aural paralysis, facial paralysis, dysgeusia, headache, aural vertigo, tinnitus, etc.

Although a cochlear implant surgery has risk, individual interested in the Programme needs not worry too much as most of the complications mentioned above will disappear when the wound heals.

Most implantees at the Prince of Wales Hospital can be discharged 24 hours after the surgery. The wound usually takes one to three weeks to heal. Implantees can resume their daily activities within the recovery period. Even children can move freely one day after the surgery.

Q. Are there any support after my surgery?


Post-surgery rehabilitative training is as important as implant surgery in the Programme. Since cochlear implant surgery does not cure deafness, patients have to get used to the sound stimulus produced by the new device so as to develop their hearing and speech ability.

The professionals of the cochlear implant team will draw up a rehabilitative plan to meet individual needs. Patients should actively and persistently participate in the training for the best outcome of cochlear implantation.

The implant does not restore normal hearing but does improve the person's ability to hear environmental sounds, to hear rhythms and patterns of speech, and to use speech reading (lip reading) better.

Q. What are the benefits of having Cochlear Implants?

Many research reports provide proof of the effectiveness of cochlear implants. Clinical trials reveal that the communica-tion ability of most of the adults enrolled in the Programme have been enhanced through listening and lip-reading. Reports also show that cochlear implantation increases the confidence of these adults and helps them lead a more active and enjoyable social life. Other adults will have better job opportunities and improved relationships with their family and friends.

Children can hear more sounds with cochlear implants after post-operative training. They can then learn speech and language, and eventually communicate with people through speech, just like a normal child. Children can be trained to hear more sounds after receiving cochlear implants. Some of them can even enter main stream education. All of the changes have a positive influence on the kids' development, their daily activities and family life.
Q. Benefits to the society

If an adult receives a cochlear implant successfully, this will not only increase his work efficiency, but also improve his ability to communicate and receive information. As they can better fit into the society, expenses for special equipment and facilities will be reduced. Moreover, if a child in the Programme can enter mainstream education, the society can also save resources on special education.

Q. Cost

Cost incurred by each patient in the Cochlear Implant Programme is approximately US$30,000 (including surgery, device, check-up and follow-up plan)

Q: When comparing the cochlear implant with the conventional hearing aid, which one is better?
The Cochlear implant cannot be compared with the conventional hearing aid as there are strengths and weaknesses of each device with respect to the working mechanism, sound reception, hearing loss level suitable for that particular device and post-surgery training.
Q: Would it be convenient to change the parts of the cochlear implant if some component is out of order?
In recent years, the implanted component of a cochlear implant has been designed to have a similar life span as human's. Yet, any man-made devices can fail and break. International experience shows that the damage rate of the implant parts is very low. Even if the parts do not work, they can be changed, while the external components can be replaced at any time.
Q: My child is active. I am very worried about him breaking some of the components after he receives a cochlear implant. What should I do?
The user should avoid hitting or dampening the components of any electronic device. There is no exception in the case of the cochlear implant. In general, provided that the user adheres to some minor precautions, anyone wearing a cochlear implant, including children, can take part in outdoor activities freely. Parents should teach their kids not to hit the incision area directly, for instance, by wearing a helmet for contact sports and removing the external component before swimming. As there are great changes in pressure during diving, cochlear implant users should avoid this activity.
Copyright © 2014 Department of Otorhinolaryngology, Head and Neck Surgery, Faculty of Medicine, The Chinese University of Hong Kong
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