This paper, written by Adam Kissiah, covers the technology transfer of the discovery, growth and expansion of the subject of the Cochlear Implant and its impact on the deaf community. This technology transfer was brought to the public light through the provisions of NASA’s Technology Utilization/Commercialization program. This Paper covers the discovery of the first accurate and patentable (US PATENT 4,063,048,December 13, 1977) description of the cochlear implant, which was designed by NASA employee Adam Kissiah, Jr. at theJohnF.KennedySpaceCenter. A brief history of the Cochlear Implant, how it works, and its commercial growth and utilization path are discussed. Kissiah had a personal hearing problem from NAVAL gunfire concussion. His discovery was aided by personal research and experience gained through prior U.S. NAVY electronics training, a Bachelor of Science Degree in Physics from the University of North Carolina, the technical environment of his employment, and participation in NASA’s activities in aerospace launch instrumentation. This knowledge, experience, personal research enabled Kissiah to recognize in the early 1970s that prior electronic designs of the cochlear implant were heretofore unproductive except for the MEDICAL aspects of the design. Kissiah’s engineering knowledge and experience was therefore applied to the discovery of an electronic substitute for the non-functioning neurological auditory sensory network within the human Cochlea. The development and production of the Cochlear Implant has become a world-wide multi-billion dollar industry that has enabled previously hopelessly deaf people to hear sounds and the human voice. It thus provided the electronic capability for deaf people to exchange intelligence by voice. It is understood and emphasized that there was widespread effort by many highly qualified individuals, and many university, government, and private technological organizations that were deeply involved in Cochlear Implant research during the 1960s, 70s and 80s. Even though Adam Kissiah can be considered the designer and inventor of the cochlear Implant, it must be stressed that many individuals and major medical research organizations, including the National Institutes of Health, the European community, and the Australian Government, were also involved in the development and marketing of a functional Cochlear Implant.
1 What is a Cochlear Implant and How Does it Work?
Helen Keller wrote in her autobiography, The Story of My Life (first published in 1905): “I am just as deaf as I am blind. 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.”
The cochlear implant (CI) is a surgically implanted electronic device that provides a sense of sound to persons who are profoundly deaf or severely hard of hearing.
A cochlear implant (10) consists of: (1) A microphone that picks up sound from the environment. (2) A speech processor that synthesizes incoming audio signals into a parallel array of sinusoidal “bands” ,or “spectral densities”, or “frequency bands” of tones, that are converted into a subsequent (parallel) array of digital stimuli. These stimuli are applied simultaneously through an established number of conductors that are terminated in a circular pattern in a (3) “transmitter” connector which is held in place behind the ear by magnetism. The stimuli are then sent by electromagnetic induction (transformer coupling) through the skin to a secondary (4) similar pattern as above receptor array of wire conductors implanted under the skin of the patient. These stimuli, still in parallel array, are then routed through the wire conductors to specific locations within the cochlea which represent specific tonal receptors of the eighth cranial nerve, which in turn lead to the hearing sector of the brain.
An implant does not “heal” a non-functioning cochlea or restore normal hearing, but it can give a deaf person enough useful reproduction of sounds to greatly enhance their capability to interpret sounds in the environment and to understand speech.
Hearing aids simply amplify sounds. They require some portion of the normal hearing mechanism to be functional. Cochlear implants bypass damaged portions of the ear and directly stimulate the auditory (eighth cranial) nerve which routes sound stimuli directly to the hearing center of the brain, which in turn recognizes the signals as meaningful sound. Hearing through a cochlear implant is different from normal hearing and often requires time to learn the entire meaning of sounds if the patient was pre-lingually deaf, or to relearn prior sound interpretations if patients became deaf after learning to speak.
In recent years extensive and competitive experimentation has been performed by many manufacturers in an effort to exploit all possible methods of synthesizing and applying the detected electrical audio stimuli to the acoustic nerve, in a continual effort to achieve the maximum possible intelligence, fidelity and clarity of audio information. The preponderance of current implants is the outgrowth of the multi-channel design described in US Patent 4063048 (10). Also, many experiments by the House Ear Institute in single conductor implants have achieved success in specialized applications. Many new strategies for increasing the effective number of audio channels being applied to the acoustic nerve have been researched, thereby helping to provide greater fidelity in a true reproduction of original audio inputs.
The American Speech & Hearing Association (AHSA) (32) has considered the cost of a cochlear implant, which varies quite widely from patient to patient. The cost varies even with respect to the location or institution from which an implant is received, since implants are available in many countries around the world. It also varies with the patient’s age, whether child, infant or adult, and with respect to the many causes and reasons for the patient’s deafness, including how long the patient has been deaf. According to the American Speech and Hearing Association, the average cost of an implant, which includes the entire surgical procedure, medical staff and hospital, plus operative medical and aural rehab is in the range of $40,000 to $60,000. Even at these seemingly exorbitant costs, researchers at Johns-Hopkins Hospital have shown that “more than $50,000 can be saved compared to the cost of more than $1,000,000 in expenses expected over a lifetime to cover the cost of children who are profoundly deaf”.
Since all cochlear implants employ the same basic design (with many ancillary variations) and have a similar range of performances, other criteria are considered when choosing a cochlear implant and comparing costs, such as the usability of external components, cosmetic factors, battery-life, whether replaceable or rechargeable, versatility of internal and external components, customer service from the manufacturer, experience of the implanting physician, qualifications of the audiologists with respect to mapping (software guided set-up for each patient), and the quality of familiarity of personnel with a particular device.
The figure below represents the basic design of the cochlear ear implant patented by Adam Kissiah in 1977.
Patent 4063048 Cochlear Implant, Adam Kissiah, Jr.
The figure below illustrates the current design of the cochlear ear impant. The basic design is virtually identical to the design from the original patent.
For comparison with modern design, refer to the design of Dr. Phillip C. Loizou, Professor in the Engineering Department of TheUniversityofTexasatDallas. See www.utdallas.edu/~loizou/cimplants/tutorial/loifig4.gif
2 History of the Cochlear Implant
The idea for artificial or electronic correction of hearing loss was first publicized in 1957 (1,10) when the French team of Djourno and Eyries implanted a patient with a single electrode inserted into the middle ear cavity near the auditory (8th cranial) nerve, and were able to transmit perceivable “noise” to the patient. Beginning in the nineteen sixties, the most noted and recognized pioneer in basic hearing stimulation research in the USA was Dr. Wm. F. House (3) of the (at that time) House Ear Institute (HEI), located in Sylmar (Los Angeles), CA. (from “Cochlear Implants, My Perspective, Wm F. House, M.D.”).
The second exceptionally recognized person or group is the well known and highly praised Dr. Graeme Clarke of Sydney, and the University of Melbourne, Australia, forerunners of Cochlear Corporation, Ltd., and Cochlear Americas, Ltd. (1, 27) They are the second (of three) major manufacturers. Dr. Clark and colleagues were highly supported by the Australian government, and their program was on par and eventually exceeded the level of development and production of Dr. House and the USA research programs.
The third major manufacturer of cochlear implants is Med-El Corporation (1, 28) in the USA, and Med-El, Ltd whose Headquarters are located in Innsbruck,Austria. Ingeborg and Irwin Hochmiar are Executive Directors. Primary U.S. Offices are in Raleigh-Durham,NC.
Many other private, governmental, and university research institutions were intensely involved in cochlear implant research. See references in the “Cochlear Implant History section of Wikipedia (1).
Early implants did not (yet) employ (1, 10) to the fullest extent the principles of synthesis of the audio spectrum, and the necessity for simultaneous (parallel) application of the place-specific-electrical audio stimuli directly to specific locations within the inner ear (cochlea) and the acoustic nerve, as specified in patent 4,063,048 Reissue 32031, 09/82. As a result, the patients of this time sensed primarily background noises, and did not enjoy the full potential of the intelligence and communication factor of the spoken word, except as an aid to lip-reading. This new life-sense did, however, achieve the highly desirable result of enabling deaf persons to emerge from the isolation of silence and enter the world of sound, which significantly improved their sense of “attachment” to society.
Subsequent to issuance of Patent 4063048 (Dec 1977) Dr. Blair Simmons and Dr. Robert White of Stanford University Stimulus Program (30), produced significant results in their early 1980s Cochlear implant development in their Bioear program in association with Biostim, Inc., and Adam Kissiah. This program is significant because it produced one of the first model implants employing specifications from Patent 4,063,048, which, as time progressed, has proved to be one of the initial basic designs of the successful implants in use today (1, 10, 14). NASA and Adam Kissiah are therefore due exceptional recognition because of the fact that NASA provided funds for patenting, advertising and transfer of this critical and vital and technology to the public through its emphasis and promotion of its system of technology commercialization. See http://www.nasa.gov/audience/forstudents/postsecondary/features/F_NASA_Spinoff.html. Also see under www.nasa.gov/, “Hearing is Believing.” More than 50 subsequent patent applications have referred to 4,063,048 as prior art in that field. This patent is therefore considered to be the INITIAL PATENTABLE DESIGN (INVENTION) OF THE COCHLEAR IMPLANT. This is one more example of a very positive discovery emanating from space research which can be added to the many thousands of electro-technology transfers by NASA.
3 The National Institutes of Health’s Role in Cochlear Ear Implant Development
In the late nineteen seventies and early eighties and beyond, as a result of research by the leaders above, and technology breakthroughs (Patent 4063048 ), the National Institutes of Health (NIH) (1, 2) significantly increased its output of research money to university, private and other research centers. The NIH provided funding and guidance under the direction of Dr. F. Terry Hambrecht, director (and successors) of the National Institutes for Neurological Diseases and Stroke (NINDS), and they also provided a central focal point for the development and production process of the cochlear implant. Contributions by private investors and donors added significant funds in promoting a high level of research in all sectors of society in development of the cochlear implant. In 1984, the Food and Drug Administration (FDA) approved the first cochlear implant for use in adults ages 18 and older. Five years later, the FDA approved the first cochlear implant for use in children ages 2 years and older. And in 2000, the FDA approved the implantation of children as young as 12 months of age for one type of cochlear implant. The above shows clearly that the National Institutes of Health and many persons and institutions were vital in bringing the cochlear implant into the public domain.
4 Commercial Development of the Cochlear Implant
As stated above, because all implants share a common basic design, there is no clear-cut consensus that any one of the implants is superior to the others. Users of all devices display a wide range of enhancements, physical designs and performance characteristics, such as FM system compatibility, usability of external components, cosmetic factors, battery life, reliability of the internal and external components,MRI compatibility, mapping strategies, customer service from the manufacturer, and the familiarity of the user’s surgeon and audiologist with the particular device.
Following is a list of some significant commercial implant providers:
- Cochlear Americas, Ltd – (10) From Company published literature) The leader in the total number of Cochlear Implants made world-wide is the Australian Cochlear Americas, Ltd., headquartered in Sydney, Australia and maker of the Nucleus Freedom implant, with over 80,000 persons implanted. Their web-site is www.cochlearamericas.com. Cochlear Limited (Cochlear) is an Australia-based company, website: www.cochlear.com which operates in the implantable hearing device industry. It is a public Company that was established in 1981, with Headquarters in Sydney,Australia. The Company employs approximately 2,500 (2011) and income of 809.6 million in 2011. The Company operates in three geographic segments:Americas,Europe and Asia Pacific. Cochlear has established special purpose entities (SPEs) for trading and investment purposes. The Company’s Cochlear Nucleus 5 system includes a cochlear implant, a sound processor, including an automatic phone detection feature. The Company’s controlled entities include Cochlear AG, Cochlear Americas, Cochlear Benelux NV, Cochlear Canada Inc, Cochlear Deutschland GmbH & Co KG, Cochlear Finance Pty Limited, Cochlear Holdings NV, Cochlear Italia SRL, Cochlear Investments Pty Ltd and Cochlear Medical Device (Beijing) Co., Ltd.
- Cochlear Limited (ASX: COH), also designs, manufactures and sells the Nucleus Cochlear implant along with the Bone Conduction Hearing Solution Baha osseointegrated bone conduction implant, with an estimated 250 000 cochlear implant/Baha recipients receiving a Cochlear Limited product since their establishment in 1981.
- Advanced Bionics-(12) (from Wikipedia and references shown) Advanced Bionics (AB) Inc. is a subsidiary of Sonova, Inc. Websites: www.cochlearimplant.com, and www.bionicear.com. Advanced Bionics is an outgrowth of Dr. William F. House’ Hearing Research Center, and later the House Ear Institute (HEI). They were the makers of the older “Clarion” model implant, and they are also known as the maker of the “Bionic Ear” Hi-resolution (Hi-Res) system. Their latest models include the Hi-Res 90k implant and the Hi-Res “Auria”, with web sites at www.cochlearimplant.com, and www.bionicear.com. AB is a company that is also a major manufacturer of heart pacemakers. Their offices are located in Sylmar, CA and France. Advanced Bionics is a global leader in developing, manufacturing and distributing the most advanced cochlear implant systems in the world, with revenues of USD 117 million in 2008. Acquired by Sonova Holding AG and working with Phonak since 2009, AB develops cutting-edge cochlear implant technology. With operations in over 50 countries. Sonova is the leading provider of innovative hearing healthcare solutions. Present in over 90 countries, and with a workforce of over 5,300 employees, Sonova generated sales of CHF 1.249 billion in the financial year 2008/09 and a net profit of CHF 284 million. For more information please visit www.sonova.com. Sonova shares (ticker symbol: SOON) have been listed on the SIX Swiss Exchange since 1994.
- Med-El, Ltd. (11) headquarters are located in Innsbruck, Austria. Ingeborg and Irwin Hochmiar are Executive Directors. Primary U.S. Offices are in Raleigh-Durham, NC. Med-El makes the Combi 40+ implant and the New Pulsar CI-100 which includes their latest and most improved Med-El technology. Med-El’s website is www.medel.com.MED-EL CorporationUSA, is also a medical devices company that develops and manufactures hearing solutions. It offers hearing systems, middle ear implants, implantable hearing devices, and speech processors. The company was incorporated in 1994 and is based in Durham,North Carolina.MED-EL Corporation operates as a subsidiary of Med-El Elektromedizinische Geräte Gesellschaft M.B.H.MED-EL Elektromedizinische Geräte Gesellschaft M.B.H. develops hearing implant solutions for children and adults. It offers cochlear implant and middle ear implant systems. The company was founded in 1977 and is based in Innsbruck,Austria. It has additional offices in Australasia,Austria,China,France,Germany,Hong Kong,India,Indonesia,Italy,Japan,Korea,Malaysia, the Philippines,Portugal,Singapore,Spain,Thailand,Vietnam, the United Kingdom, and the United States, as well as Latin America and the Middle East.
- Others manufacturers include: MXMLaboratories – www.mxmlab.com. Digisonic, Inc.; AllHear, Inc., Aurora, Oregon; and Allhear:[email protected] [update].
In the European Union Countries (EU), an additional device manufactured by Neurelec, of France, is available. Each manufacturer has adapted some of the successful innovations of the other companies to its own devices. There have been news reports of other organizations working to develop cochlear implants, in South Korea by the Seoul National University Hospital (Wiki #53) and in India by a branch of the Defense Research and Development Organisation (Wiki India).
5 Effect of the Cochlear Implant on Society
The COCHLEAR IMPLANT is a multi-billion dollar industry which includes thousands of persons in the medical profession, specialized medical research and surgical institutions, and research projects in hundreds of colleges and universities around the world.
The advantages of attaining, or regaining the sense of hearing is profound. The Cochlear implant has enabled thousands of persons to gain highly beneficial employment that was previously impossible to even consider, thus increasing the enjoyment and quality of many lives. According to the U.S. Food and Drug Administration (FDA), as of December 2010, approximately 219,000 people worldwide have received implants. In theUnited States, roughly 42,600 adults and 28,400 children have received them.
6 Controversy in the Deaf Culture: The Social-Emotional Impact of the Cochlear Implant on Children
According to a study by Pace University, Janna R, Stein, January 2007, (24) findings indicate that “deaf children have difficulty socializing when they are with a group of hearing peers. Deaf children also have lower self-esteem than their hearing peers”. This study was conducted to examine whether deaf children with cochlear implants differ in perceived acceptance and competence as compared with their hearing peers. Participants were 8 deaf children, ages 5 to 6, who received a cochlear implant at the New York University Cochlear Implant Center at least 1 year prior to participation. Findings also suggest that “children with cochlear implants do not differ from hearing children on any self-perception scales. Children with cochlear implants who perceive themselves in a generally positive manner were found to interact more, have more verbal exchanges, and initiate more new topics when engaged in a social relationship with a hearing peer”.
The American Medical Association (AMA) and the American Academy of Otolaryngology-Head and Neck Surgery (16) now consider the cochlear implant to be a viable, even standard treatment for profound deafness for children. The concern after implant of children is the unknown territory of what is the best training routine for the child, whether simply “mainstreaming with other children”, with oral training in the normal population, or is a strict, specialized routine required? The reality is somewhere in between, considering the “developmental age” of the child and whether the child has become proficient in sign language or other means of communication. “All new implantees require monitoring by professional trainees (teachers) and a significant involvement by parents”. Many children will not have access to other deaf children and continued exposure to sign language, and eventually acquire “normal” levels of education and rates of learning. Others require on-going special education and assistance.
The Deaf community objects to the “forced “lack of continued exposure to American Sign Language (ASL), and a resulting “cultural genocide” attitude in the Deaf world. (Wikipedia Ref 24). It has been reported in the Journal of the American Medical Association (16) Medical News (JAMA) in the May, 2012 issue of the archives of Otolaryngology-Head and Neck Surgery (16) that the objection to implantation of deaf children is diminishing. There is still much opposition today but is the attitude is softening. As the trend for cochlear implants in children grows, deaf-community advocates have tried to counter the “either or” formulation of voice versus sign language to a “both/and” approach; some schools now are successfully integrating cochlear implants with sign language into their educational programs, however, some opponents of sign language education argue that the most successfully implanted children are those who are encouraged to listen and speak rather than overemphasize theirASLskills”.
GallaudetUniversity(31), considered to be the “Harvard “of the Deaf community, has been watched closely by all sides in the debate for its position on cochlear implants. Mercy Coogan, Director of Public Relations at Gallaudet, says the university doesn’t have a stand on cochlear implants. “We try to be a forum where people can look at it objectively,” Coogan says. “A university is where you debate issues, and then make judgments based on that debate”.
Gallaudet faculty (31) members John B. Christiansen, PhD., and Irene W. Leigh, Ph.D led a study (published5/17/2004) that showed the changing attitudes of parents of the deaf community and parents of deaf children regarding pediatric cochlear implantation. “Clearly, many people in the deaf community, including faculty, staff, students and alumni at Gallaudet University are much more open minded about cochlear implants today than they were 5 or 10 years ago, although some still question implants”, the authors explain.” To ensure optimal use of the cochlear implant, parents need to remain involved in their child’s social and educational development”.
Nancy Bloch, The National Association of the Deaf, said, “The NAD takes no position on adult implantation for this is believed to be an individual choice”. The NAD recently released a new position statement on cochlear implants, which can be found on the NAD web site. ”The NAD recognizes the right of parents to make fully informed decisions on behalf of their deaf children with regard to implantation. Implants are seen as the panacea for deafness, which only serves to perpetuate devaluative societal attitudes towards deafness and deaf people. Simply put, while the device provides the ability to receive auditory signals, the ability to make sense of and use these signals for meaningful dialogue varies greatly from person to person”.
Donna Sorkin’s Rebuttal: Donna Sorkin, Fmr. Executive Director, The Alexander Graham Bell Association for the Deaf And Hard Of Hearing:
“I disagree that cochlear implants are viewed as a panacea. AG Bell, implant centers and professionals in the field always emphasize that families that pursue this option for children must be prepared for the work that follows to make full use of the technology. Additionally, those of us familiar with cochlear implants (and I count myself amongst those, both as a cochlear implant user and as someone who has advised hundreds of families) know that the cochlear implant is a tool to communication and that it does not provide normal hearing. I don’t understand why some deaf people feel that because individuals and families have pursued the cochlear implant option their choice somehow devalues others’ choices for manual communication.”
7 Closing Comments
The evolution of the cochlear implant has rendered deafness to be a matter of choice to human beings, and not a life sentence of silence to persons whom have lived half a normal life, and suffered a very painful, either sudden or gradual, severe loss of hearing. Rush Limbaugh is an example of a professional person who suffered an excruciating severe hearing loss in mid-career and was restored to full capacity by a cochlear implant. The vast majority of hearing persons have complete respect for persons who consider themselves to be exclusive and proud members of the Deaf community, and most members of the hearing society DO understand and sympathize with the deaf community and their cultural pride, while it is also our hope that deaf persons, especially parents, will continue to keep an open mind, as they have in recent years in increasing numbers, toward looking seriously at the pros and cons of implants with respect to each individual’s own unique situation.
From the time we are born, and each day of our lives we are acquiring new knowledge and gaining new capabilities. From kindergarten to high school graduation, to a college degree, to PhD, MD or whatever we choose, we gain higher levels of achievement each step of the way. A Deaf person with a cochlear implant in reality is considered to have a capability that is in addition to his or her sign language capability that renders them superior to the communication abilities of hearing-only persons in that they can communicate with both the worlds of the deaf and hearing. Accepting an implant does not require a person to leave the Deaf culture and be limited to the hearing only world. Millions of immigrant children entering this country have learned the language of their new country while fully retaining the language (and culture) of their parents, and have lost nothing in the process. Likewise, cochlear implant patients are not required to reject or denounce a single prior friend, business or family member to receive the new benefit of hearing. The attainment of a cochlear implant is simply a new capability for learning and for communicative interaction with greater numbers of the human population. Indications are that it is very likely that significantly increasing numbers of the Deaf population will eventually choose, whether it be in a decade, a generation or a lifetime, that the cochlear implant is a very positive choice as an aid for the enrichment of life for themselves and for their children.
To see the true impact of the technology, watch these videos:
Adam M. Kissiah, Jr.June 22, 2012
- Wikipedia – Cochlear Implant – History.
- The Cochlear Implant NIH Publication number 11-4798 (2011-03-01). “Cochlear Implants” National Institute on Deafness and Other Communication Disorders.
- U.S.Department of Health & Human Services – National Institutes of health – Research Portfolio Online Reporting Tools (RePORT – Reports, Data analyses of NIH Research Activities.
- W.F. House (May-June 1976). “Cochlear Implants”. Annals of Otology, Rhinology, and Laryngology 85 (suppl 27) (3pt2): 1-93.PMID779582.
- F. Blair Simmons (July 1966). “Electrical Stimulation of the Auditory Nerve in Man”.
- Archives of Otolaryngology84 (1) 2-54.PMID5936537.
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- Bionic ear prototype,NationalMuseumofAustralia. http://www.nidcd.nih.gov/health/hearing/coch.html#c.
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- Adam Kissiah, Jr. Cochlear Implant Technology by Adam Kissiah, Jr.
- Adam Kissiah, Jr.- www.hearagain.org.
- Adam Kissiah, Jr. www.nasa.gov-NASA Spinoff-Hearing is Believing.
- NASA-Cochlear Implant Inventor Recognized 25 years Later, http://www.nasa.gov/centers/kennedy/news/releases/2002/release-20020913.html.
- Adam Kissiah, Jr. NASA’s Office of the Chief Technologist NASA’s Office of the Chief Technologist recognizes technology developed by NASA that has benefits for the entire nation. In the article “Hearing is Believing”. http://www.sti.nasa.gov/tto/spinoff2003/hm_3.html.
- The social-emotional impact of cochlear implants on children – Janna R Stein,PaceUniversityJanuary, 2007.
- GallaudetUniversity– Cochlear Implants in Children – John B. Christiansen, and Irene Leigh, January, 2002.
- Journal of the American Medical Association, Medical News (JAMA) in the May, 2012 issue of the archives of Otolaryngology-Head and Neck Surgery.
- Innovation and Industry Development: The Case of Cochlear Implants by Andrew H. Van de Ven and Raghu Garud 31 Ashley Nicole Norkus, History of theCochlearImplant-BloomsburgUniversity, June, 2007.
- NASA, Spinoff Article on engineer Adam Kissiah’s contribution to cochlear implants beginning in the 1970’s.
- Cochlear Implants, Information from the National Institutes of Health. “Defence Research and Development Organisation” develops affordable cochlea implant”. www.indiatimes.com. 2012-05-20. Also http://timesofindia.indiatimes.com/city/bangalore/Defence-Research-and-Development-Organisation-develops-affordable-cochlea-implant/articleshow/13309792.cms. Retrieved20 May 2012.
- Bae Ji-sook (2010-02-28). “Procedure Gives Hearing to Auditory Disabled”. TheKoreaTimes. hhttp://www.koreatimes.co.kr/www/news/art/2010/02/147_61550.html. Retrieved 2010-03-05.
- “The Cochlear Implant Controversy, Issues and Debates”.NEWYORK: CBS News.September 4, 2001. http://www.cbsnews.com/stories/1998/06/02/sunday/main10794.shtml. Retrieved 2008-11-09.
- NAD Cochlear Implant Committee. “Cochlear Implants”. Archived from the original on 2007-02-20. http://web.archive.org/web/20070220131900/http://www.nad.org/site/pp.asp? Solomon , Andrew (1994-08-28). “Defiantly deaf”. The New York Times. http://query.nytimes.com/gst/fullpage.html?res=9A00E2D91639F93BA1575BC0A962958260&sec=health&pagewanted=10. Retrieved 2010-04-30.
- U.S.Patent 4,063,048,December 13, 1977, Adam M. Kissiah, Jr., Reissue 31031, Sept , 1982 .
- The Social-emotional impact of cochlear implants on children – Janna R. Stein,PaceUniversity, 2007.
- GallaudetUniversity-Cochlear Implants in Children: John B. Christiansen, Irene Leigh Jan, 2002 .
- Cochlear Corporation, Ltd. and Cochlear Americas, Ltd. Annual Report 2011 Consolidated results – 2011 809,646.
- Med El, Ltd. Med-El’s website is www.medel.com.
- Advanced Bionics is an outgrowth of Dr. William F. House’HearingResearchCenter, and later the House Ear Institute (HEI). Websites: www.cochlearimplant.com, and www.bionicear.com
- Annals of the New York Academy of Sciences volume 405, cochlear prostheses: An International Symposium pages 377-386, June 1983 Atlas, L.E. Herndon M.K., Simmons, F.B., Dent, L.J. and White, R.L. (1983), RESULTS OF STIMULUSANDSPEECH-CODING SCHEMES APPLIED TO MULTICHANNEL ELECTRODES.
- GallaudetUniversity- Cochlear Implants in Children – Ethics and Choices -John B Christiansen and Irene W. Leigh
- The American Speech-Language-Hearing Association is the professional, scientific, and credentialing association for more than 150,000 members and affiliates who are audiologists, speech-language pathologists, and speech, language, and hearing scientists in the United States and internationally.
- See The design of Dr Phillip C. Loizou, Professor in the Engineering Department of The University ofTexasatDallas. www.utdallas.edu/-loizou/cimplants/tutorial/loifig4.gif.