Cochlear Implants - Facts

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What is a cochlear implant

A cochlear implant is an electronic device designed to provide sound information for adults and children who have a profound sensironeural hearing loss (nerve deafness) in both ears and show no ability to understand speech through hearing aids.

The first research on cochlear implants was conducted in France 30 years ago. Since then, cochlear implant technology has evolved from a device with a single electrode or channel to systems that transmit more sound information through multiple electrodes or channels.

(Source: Issues and Answers--written by the Cochlear Corporation, as of January 1994.)

Contact information - WITHDRAWN

This section used to have contact information for various institutions concerned with cochlear implants. It was relevant in the pre-search engines era. However, the information became obsolete and now search engines such as Google can be used to locate up-to-date information. Therefore, the information in this section was withdrawn.

Statistics and notes about cochlear implants as of 1995

(Contributed by Eric Smith at 26 Sep 1995.)

The most commonly used CI processor now is the Spectra, which is significantly better than earlier ones. As an example, in 1985, using the WSP processor with the F0/F2 programming, the average percentage of words identified correctly from a sentence test by deafened-adult test subjects who had their implants for at least six months was 12% without lipreading. That means they missed 88% of the words. They did much better with lipreading of course. But since then, as the processors have improved, the 12% has increased to 78%, and that's still without lipreading.

(Contributed by Sandra De Quesada at 24 Sep 1995.)

The following information is up to date as of May 1995.

According to the NIH Consensus Statement (from a conference which was held between May 15-17, 1995), there are more than 12,000 people worldwide who have CIs.

From the "Issues and Answers" printed by Cochlear Corporation in April 1994:

"Presently, over 10,000 people worldwide have received various types of cochlear implants. The number of individuals worlwide who have received the Nucleus 22 Channel Cochlear Implant System include over 5,000 adults and over 3,000 children."

(Contributed by Joseph P. Riolo at 15 Apr 1993.)

Here are some statistics and notes about cochlear implant for you to munch (the information below is up to date as of 1993):


  1. An untitled fact sheet sent by Cochlear Corporation.
    2 pages.
  2. Issues and Answers (mini-system 22) by Cochlear Corporation.
    22 pages.


over 7,000 people with various types of implants worldwide
over 1,000 (out of 7,000?) are children

over 2,500 people with the 22 Channel Implant worldwide
over 450 (out of 2,500?) are children

(my own computation: 450 children / 2 years = 225 children per year. 225 children out of 3-4,000,000 children born each year in U.S. = 0.005625%-0.0075%)

total cost from beginning to end is generally over $25,000.00

(my own computation: 2,500 * $25,000.00 = $62,500,000.00 so far)

Nucleus 22 Channel Cochlear Implant is released for use in adults in 1985 and in children in 1990.


(I am not going to copy everything. I only select notes that looks interesting.)

"A cochlear implant is an option which may allow individuals to interact with the hearing world and to broaden their educational, occupational and social opportunities."

"The entire process happens in milliseconds so that a 22 channel implant user can virtually hear sounds as they occur. Signals are sent continuously if there is sound present in the environment. Special circuitry exists in the speech processor to reduce unwanted background noise."

"The Mini System 22 is powered by a single rechargeable AA battery for low-cost operation and convenience."

"However, there are no tests to predict the level of benefit a particular individual will receive. In general, people who have heard and spoken for a number of years before they became deaf are able to use an implant to greater advantage than those who are born deaf."

"The external components are removed before swimming. Scuba diving, however, is not recommended because of extreme pressure changes."

"The long term effects of implanting or using a cochlear implant are unknown. Potential hazards include new bone growth in the cochlea or deterioration of the nerve cells."

"The warranty on the internal parts is 5 years. The speech processor and headset (excluding batteries and cables) have a 3-year warranty that can be extended with optional one- or two-year renewable service contracts."

"When you receive a cochlear implant, you form a lifetime relationship with the company that manufactures and services it. You should be confident that the manufacturer has a record that warrants your trust." (translation: symbiosis)

Questions and Answers about Cochlear Implants

Questions were posed by Robert Rourke at 15 Jul 1994.
Answers were given by Chris deHahn at 15 Jul 1994 and Stefan Brill, Institut f. angewandte Physik, Uni Innsbruck, Austria, EMail: at 20 Jul 1994.

We would like to know if the medical community has ever considered the following questions, which many people in the Deaf community are asking.......

  1. Is it true that a child's skull continues to grow as s/he ages? Would this require repeated surgeries?

    Chris: Yes, and no. The implant is in the mastoid area and has plenty of room for growth.

    Stefan: This needs some more explanation. It is true that the skull grows, of course. Because not all parts of the skull grow, it doesn't require repeated surgery . The cochlea for instance stops growing at a very early age, as there are certain areas of the temporal bone which also stop growing. Since this seems to be a faq, I will go into details in a separate post sometime.

  2. Does the cochlear implant include a battery that is inside the head? If it has a battery, how often does it need to be replaced, and how much does the replacement cost?

    Chris: No. The implant is passive (i.e. no power). The power is fed to the implant from the processor, which is external to the body and has a rechargeable battery. The life of the rechargeable battery is at least several years.

    Stefan: Chris is completely right here. The implant doesn't include a battery. The power supply for the implanted part of the CI is done via a high frequency transmission line. The external part of the CI (the CI processor) has a sender which is placed behind the ear above the internal part. The sender transmits power and signal. If the implantee takes off the sender, there is no power nor signal nor acoustic sensation. The CI processor of course has its own battery or rechargeable accumulator. It can be easily exchanged, like walkman's batteries.

  3. If continuing technology results in more advanced implants for the future, would an implant recipient of today need another "full" operation in the future to keep up to date? If so, would this new operation be equally as expensive?

    Chris: According to several friends that have implanted their children, half of the cost of the CI is the processor (approximately $15K). The implant does not have to be updated, only the external processor. That is, if the recipient is pleased with the xx electrode implant and does not wish to change to a yy electrode implant (xx and yy denote the number of electrodes in the implant).

    Stefan: In most cases he would need another operation. Some of the older implants are slow. Some provide only analogue stimulation. Some are single channel devices. If, for instance, the recipient would want to step up to a multi channel device having had a single channel device before, he would need full surgery again. Well, almost. The surgeon would not need to drill the bone again. The risk of damaging the facial nerve would not be there again. The operation would be a lot quicker.

    Some patients (about 400 to 500, as far as I know, mostly in the UK, in Spain and the US) have a plug behind the ear. You read right, A PLUG ! (I hate this thing. I have seen several patients being very happy with it, but I still hate it.) In this plug implant, the electrode plates inside the cochlea are directly connected to the plug outside. With this special case of implant, it is possible to simply change the external processor to upgrade. In fact, these patients are very interesting for the development of new coding and stimulation strategies. Actually, Blake Wilson's "CIS" strategy has been developed with those patients.

  4. Of all the cochlear implant operations to date, what percent are considered a "success"?

    Stefan: I think, this cannot be answered. Until now, there have been more than 7.000 implantations worldwide. There is a bunch of different CIs worldwide, even a Chinese one. Anything would be nothing more than a guess.

    At the end of August, here in Tyrol we will have a meeting of all the people involved in the clinical study with our new CI. I will post the till-then-found results afterwards, and these will be facts.

  5. What is the definition of a successful operation?

    Stefan: It is to simple to define the operation a success or not a success.

    There are only a few cases when the implant recipient has an open set speech understanding immediately after the operation, i.e. immediately after the first fitting of the processor.

    I think there are several steps how to define the implantation a success:

    • How good can the patient control his own speech ?
    • Does the patient recognize environmental sounds and what is the percentage of correct recognitions ?
    • What is the percentage of correctly recognized speech sounds (i.e. vowel / consonant / closed set word / open set word / sentence recognition) ?
    • Is the patient able to use the phone without problems ?
    • How does communication work in a environment with many speaking people ?

    In some languages, very advanced at least in English and German, we have a whole set of different tests, most of which measure speech intelligibility at different levels.

  6. Can an implantee recipient go swimming? If not, what would happen if s/he accidentally fell into the water?

    Chris: Yes, with the processor and coupler off. CI water accidents are similar to hearing aid water accidents. Often, the HA can be dried out afterwards and be fully functional. There's no reason why the CI processor cannot be revived in a similar fashion.

    Stefan: Chris is right. No problem with water, the implant is completely under the skin which is water proof. The implantees with the plug need a cap over the plug, at least they should dry the plug with a paper towel afterwards. It is not recommended to drop the external parts into water. It is the same thing as with any electronic device.

  7. If an implant recipient decided to no longer "use" an implant, how would s/he go about removing it?

    Chris: The coupler and processor are taken off, just like hearing aids are taken off nightly before going to sleep. There's no need to remove the implant. If this is desired, it requires surgery.

    Stefan: This is correct. First approach would be to take off the sender or to switch off the external processor. If the patient doesn't have a pathologic tinnitus, absolute quietness will rule then. If the recipient would want to remove the implant, this would need surgery.

  8. What are all the risks associated with cochlear implant surgery?

    Stefan: All the risks every non-brain head surgery has. Because of some anatomical reason, with any microsurgery of the ear there is a special risk. If the surgeon doesn't know his job, he can damage the facial nerve. This would result in the patient's temporary or partly or full loss of ability to control the facial muscles on one side.

  9. Which insurance companies will cover the cost of the cochlear implant surgery, and what percentage of the surgery will they cover?

    Chris: I don't know which ones or what percentage, but of the five families I know that have implanted their children, none of them could have done it without insurance coverage. Their insurance paid all or part of the procedure, hardware, and therapy (mapping).

    Stefan: Sorry, I don't know the answer to this question. This is specific to each country.

  10. If children do not want a cochlear implant, do the parents have the final authority to force them to do so?

    Stefan: Sorry, I don't know the answer to this question. This is specific to each country.

  11. Are there any legal steps a child might take to prohibit the surgery?

    Stefan: Sorry, I don't know the answer to this question. This is specific to each country.

  12. What is the outcome of cochlear implant surgery after five years? Ten years? Twenty years? What is the exact length of time that cochlear implants in infants have been studied, and what were the exact guidelines in determining the FDA's approval?


    1. The _maximum_ outcome is open speech understanding in not too crowded rooms, using the phone without problems and a not-very-good reception of music. This is _possible_ after five years with good patient conditions, with a good implant and a lot of training and motivation. Please don't misunderstand me here: I don't say this is the average result. I don't say this works without a lot of training. I don't say this is possible with all patients. I don't say this works with every implant.
    2. I don't know when the first children were implanted, but I can find out.
    3. I don't know the internal guidelines of the FDA, maybe somebody on this list knows better. I also would be interested.
  13. If the results of cochlear implants are still considered untested, why is it that the FDA gave final approval to "test" on infants?

    Stefan: With more than 7.000 implantations till now, I think the results cannot be considered untested. This question is about the same as 12.3). If anybody on the list has an idea about the FDA's guidelines, please speak up.

  14. Does the FDA have the input of any culturally Deaf people in any capacity?

    Stefan: I don't know. Probably the Deaf community knows better.

  15. Does the FDA view the cochlear implant as a pill to "cure a hearing problem"? Isn't that the same as trying to change an African American person into a white person? Is the FDA working on a similiar surgery for people of other cultures?


    1. I don't know. Its again nearly the same question as 12.3, which sounds about: "What were the FDA's internal decision guidelines for CI approval?"
    2. I don't agree in this point. A hearing person can turn deaf. A white person cannot become an African American. Being African American is being member of an ethnicity, being deaf is not.
    3. As far as I know, the FDA doesn't develop anything. It just gives or refuses approval, and it doesn't give approval very easyly. From my European point of view, the FDA seems to be very resrictive. I.e. a company trying to sell any medical device or "pill" in Europe can get the respective country's approval quite easyly if it already has the FDA approval, even in Scandinavia and Germany. The other way round: If it already has for instance the German approval, this means nothing to the FDA.
Last update date: 
2005 Nov 12