2nd Part of Article

British Member of Parliament Jack Ashley received a cochlear implant in 1994 at age 70 after 25 years of deafness, and reported that he has no problem speaking to people he knows one on one, even on the telephone, although he might have difficulty with a new voice or with a full of activity conversation, and still had to rely to some amount on lip-reading. He described the robotic sound of human voices perceived through the cochlear implant as "a croaking dalek with laryngitis". Even modern cochlear implants have at most 24 electrodes to put back the 16,000 delicate hair cells that are used for normal hearing. However, the sound superiority delivered by a cochlear implant is often good quality enough that many users do not have to rely on lip-reading. American radio host Rush Limbaugh, who has severe hearing difficulties, says that everything sounds normal apart from that he cannot decipher the melody of new music that he had not heard prior to becoming deaf.

Adults who have grown up deaf can find the implants ineffective or irritating. This relates to the specific pathology of deafness and the time frame. Adults who are born with normal hearing and who have had normal hearing for their early years and who have then progressively lost their hearing tend to have better outcomes than adults who were born deaf. This is due to the neural patterns laid down in the early years of life, which are crucially important to speech perception. Cochlear implants cannot overcome such a problem. Some who were orally educated and used amplifying hearing aids have been more successful with cochlear implants, as the perception of sound was maintained through use of the hearing aid.

Many individuals who use sign language believe they have no use for sound. Individuals who are deaf use sign language and an interpreter to communicate with those who use spoken languages, in the similar way that an individual who only speaks English but wants to meet with an individual, who only speaks French, would utilize an interpreter.

Children without a working auditory nerve may be helped with a cochlear implant, although the results may not be best. Patients without a feasible auditory nerve are usually identified during the candidacy process. Less than 1% of deaf individuals have a missing or damaged auditory nerve, which today can be treated with an auditory brainstem implant. Recent research has suggested that children and adults can advantage from bilateral cochlear implants in order to aid in sound localization and speech understanding.

Risks and disadvantages:

Some effects of implantation are irreversible; while the machine promises to provide new sound information for a recipient, the implantation process unavoidably results in damage to nerve cells within the cochlea, which often results in a permanent loss of most residual natural hearing. While fresh improvements in implant technology, and implantation techniques, assure to minimize such damage, the risk and extent of damage still varies.

In addition, while the machine can help the recipient improved hear and understand sounds in their environment, it is cleanly incapable of replicating the quality of sound processed by a natural cochlea. As a result, some recipients can only distinguish the difference between simple sounds, such as ringing phone bell and a doorbell, while others can clearly understand speech in quiet environments. The achievement rate depends on a variety of factors, including technology used and condition of the recipient's cochlea.

The FDA reports that cochlear implant recipients may be at higher risk for meningitis. A study of 4,265 American children, who received implants between 1997 to 2002, concluded that recipient children had a danger of pneumococcal meningitis more than 30 times greater than that for children in the general population. A later, UK-based, study found that while the incidence of meningitis in implanted adults was significantly higher than the general population, the occurrence in children was no different than the general population.

There are strict protocols in choosing candidates to avoid risks and disadvantages. Batteries of tests are performed to make the deCochlear Implants ion of candidacy easier. For instance, some patients suffer from deafness medial to the cochlea - typically acoustic neuronal. Implantation into the cochlea has a low success rate with these people as the artificial signal does not have a healthy nerve to travel along. With careful selection of candidates, the risks of implantation are minimized.

Ethical issues:

Discussions within the deaf community continue to fuel controversy and emotional personal debates about health, rights of the individual citizen, language, ethics, and the effects of the device on deaf society. For some in the deaf group of people, Cochlear Implants are an affront to their culture as they view it, is a minority threatened by the hearing majority. This has been a difficulty for the deaf community and goes back as far as the 18th century with the argument of manuals vs. orals. Another part of the controversy concerns the essential right of an individual to choose a language versus an individual as a young child having a form of communication and language chosen for them. In the history, many adults whose first language is sign language endured policies created by medical and educational governing bodies that enforced the use of spoken language and use of hearing aids on them. One argument made by those in the deaf community opposed to cochlear implants is that implantation of CI's in young children is just another form of mistreatment. In the past, deaf individuals have successfully advocated change to improve human rights for individuals, and they continue to work to supporter for change that will help children who are born with loss of hearing.

Cochlear implants for congenitally deaf children are often considered to be most effective when implanted at a young age, during the critical period in which the brain is still learning to understand sound. Hence they are implanted before the recipients can decide for themselves. Critics question the ethics of such invasive optional surgery on children. They point out that manufacturers and specialists have exaggerated the efficacy and downplayed the risks of a procedure that they stand to increase from. On the other hand, Andrew Solomon of the New York Times states that "Much National Association of the Deaf propaganda about the danger of implants is alarmist; some of it is positively inaccurate."

Much of the strongest objection to cochlear implants has come from the deaf community, which consists largely of pre-lingual deaf people whose first language is a signed language. Regardless of the fact that to be deaf is to lack the ability to hear, many individuals who are deaf and the deaf community do not share the view of deafness held by many hearing parents of deaf children, who regard deafness as a disability to be "fixed". Individuals who are deaf rejoice their diverse culture. On the other hand, many people feel that refusing to implant deaf children is unethical, comparable to refusal to treat any other handicap or disease that can be effectively alleviated. Many individuals who can hear or who have become deaf due to injury or illness are not comfortable with the thought of a child who is short of the sense most commonly associated with human language. Individuals who are deaf may feel that implants are just another form of mental and physical abuse in the long history of punishments, mistreatment, and pain they have had to endure.

The clash over these opposing models of deafness has angered since the 18th century, and cochlear implants are the latest in a history of medical interventions promising to turn a deaf child into a hearing child, or, more accurately, into a child with a mild or moderate hearing impairment.

Critics argue that the cochlear implant and the subsequent therapy often become the focus of the child's identity at the expense of a deaf identity and ease of communication in sign language. Measuring the child's success only by their mastery of hearing and speech will lead to a poor self-image as "disabled" (because the implants do not produce normal hearing) rather than having the healthy self-concept of a proud deaf person.

Some writers have noted that children with cochlear implants are more likely to be educated orally and without contact to sign language. Also, children with implants are often isolated from other deaf children and from sign language. Instead they are 'married' to a team of hearing experts who will monitor their cochlear implant and adjust the speech processor, at great expense. Children do not always receive support in the educational system to fulfill their needs as they may require special education environments and Educational Assistants. According to Johnston, cochlear implants have been one of the technological and social factors implicated in the decline of sign languages in the developed world. Some of the more extreme responses from deaf activists have labeled the widespread implantation of children as "cultural genocide". As cochlear implants began to be implanted into deaf children in the mid to late 1980s, the deaf community responded with protests in the US, UK, Germany, Finland, France and Australia.

Opposition continues today but is softening. As the trend for cochlear implants in children grows up, deaf-community advocates have tried to counter the "either or" formulation of oralism vs. manualism with a "both and" approach; some schools now are successfully integrating cochlear implants with sign language in their educational programs. However, some opponents of sign language education quarrel that the most successfully implanted children are those who are encouraged to listen and speak rather than overemphasize their visual sense. Significantly, deaf individuals have a high rate of illiteracy due to the phonetic nature of western writing systems; it is consideration that cultivating the auditory senses will help a hearing impaired child avoid this problem. However, others (mainly deaf people who have been educated in decades past) feel that the high levels of relative illiteracy are mainly due to profoundly deaf children being taught orally despite being sign language users and not being able to fully understand speech. Oral education in the past, though, was very much different from the approaches nowadays, which have the benefit of hearing with cochlear implants. Previous generations relied heavily on lip-reading. A fairly high percentage of today's implanted persons can hear well or have only reasonable hearing loss and, depending on the individual, do not depend on lip-reading at all.

Parents and children alike have been interviewed to discuss their opinions on cochlear implants. Many children discuss the fact that many of their parents never asked them or discussed the idea of a cochlear implant with them. While some discuss the fact that their parents asked them about it and discussed it with them and that made it better. Young adults seem to have the most horrible experiences mainly for cosmetic reasons but for some the cochlear implants just not work for them. If a child is placed into a mainstream setting it makes it difficult for them because they feel like they do not fit in with their peers and cannot fully identify with the deaf community. One interviewee in the Christiansen and Leigh study states “In high school it was the worst time for me with the cochlear implant because I was really trying to discover my identity with the cochlear implant. I never accepted my deafness. And the cochlear implant in some ways showed me that no matter what, the moment I take it off I’m deaf. I’ll never be hearing 24 hours.”

A 2007 study about attitudes of young, implanted people shows that although they are aware of the negative effects, their feelings about the implantation are overwhelmingly positive. None of the teenagers participating in the study critic-Cochlear implanted their parents for making the deCochlear Implants ion. They developed a positive identity and felt that they belonged to both the hearing and deaf worlds although only some of them use both spoken and sign language.

Common Myths and Misconceptions:

A lack of clarity on a seemingly confusing theme causes myths and misconceptions to arise. The term ‘Bionic Ear’ seems to allude to the idea that a cochlear implant will provide a cure for what nature did not provide. However, present technologies are not adequately advanced for cochlear implants to be considered a counterpart to a normal human ear.

The myth that a cochlear implant will heal deafness is the one that causes the most controversy among the deaf and hearing community, especially because numerous in the deaf community believe that their deafness is a gift and attempts to fix or cure deafness it is not considered respectful to the members of that community.

Another myth that may appear alarming to people is the thought that cochlear implants will mark an end of the deaf community. There is much discussion in the deaf community about its future, not only because of cochlear implants, but also because of the implications of genetic research for correcting hereditary deafness. This technology may in fact reduce the size of the deaf community; however one must also look at the idea that many deaf people are welcoming of those individuals that have had cochlear implantation. Many of the children who have received cochlear implants still go to schools for the deaf and as many articles have discussed school and other outside activities with other deaf students increase the reach of deaf culture because only 10% of deaf children have parents who are deaf. Proof of the close-knit relationship of the deaf community, even through the advancement of cochlear implants can be seen at Gallaudet University. Every year at Gallaudet they have been counting the number of students that are admitted with cochlear implants and for the past four years that they have been counting the number doubles. Even at the elementary school on Gallaudet's campus the inclusion of the thought of cochlear implants can be seen in the children's books as well as a doll known as "C.I” Joe. However, there are counterarguments to this myth and that is some deaf people believe that cochlear implant surgery on young deaf children will decrease the numbers of deaf people and the idea of a cochlear implant adds to the understanding as deaf being a disability. The only problem with this dispute is that even if a child has a cochlear implant that does not necessarily take them out of the deaf community as a whole. Many deaf people will fight the point that it will take more than an implant to make deaf identity go away.

Functionality:

The implant works by using the tonotopic organization of the basilar membrane of the inner ear. "Tonotopic organization", also referred to as a "frequency-to-place" mapping, is the way the sorts out different frequencies so that our brain can development that information. In a normal ear, sound vibrations in the air lead to resonant vibrations of the basilar membrane inside the cochlea. High-frequency sounds (i.e. high pitched sounds) do not pass very far along the membrane, but low frequency sounds pass beyond in. The movement of hair cells, located all along the basilar membrane, creates an electrical disturbance that can be picked up by the surrounding nerve cells. The brain is able to interpret the nerve activity to determine which area of the basilar membrane is resonating, and therefore what sound frequency is being heard.

In individuals with sensor neural hearing loss, hair cells are often fewer in number and damaged. Hair cell loss or absence may be caused by a genetic mutation or an illness such as meningitis. Hair cells may also be destroyed chemically by an ototoxic medication, or just damaged over time by excessively loud noises. The cochlear implant bypasses the hair cells and stimulates the cochlear nerves straight using electrical impulses. This allows the brain to interpret the frequency of sound as it would if the hair cells of the basilar membrane were functioning properly.

Processing:

Sound received by the microphone must after that be processed to determine how the electrodes should be activated. Filter-bank strategies use Fast Fourier Transforms to divide the signal into different frequency bands. The algorithm chooses a number of the strongest outputs from the filters, the exact number depending on the number of implanted electrodes and other features. These strategies highlight transmission of the spectral aspects of speech. Although coarse temporal information is presented, the fine timing aspects are as yet poorly perceived and this is the focal point of much current research.

Feature extraction strategies used features which are rare to all vowels. Each vowel has a fundamental frequency (the lowest frequency peak) and formants (peaks with higher frequencies). The pattern of the fundamental and formant frequencies is specific for different vowel sounds. These algorithms try to recognize the vowel and then emphasize its features. These strategies emphasize the transmission of spectral aspects of speech. Feature extraction strategies are no longer widely used.

Transmitter:

This is used to transmit the processed sound information over a radio frequency link to the internal portion of the device. Radio frequency is used so that no physical connection is needed, which reduces the chance of infection and pain. The transmitted attaches to the receiver using a magnet that holds through the skin.

Receiver:

This component receives directions from the speech processor by way of magnetic induction sent from the transmitter. (The receiver also receives its power through the transmission.) The receiver is also a sophisticated computer that translates the processed sound information and controls the electrical current sent to the electrodes in the cochlea. It is embedded in the skull at the back the ear.

Electrode array:

The electrode array is made from a type of silicone rubber, while the electrodes are platinum or a similarly highly conductive material. It is connected to the internal receiver on one end and inserted into the cochlea deeper in the skull. (The cochlea winds its way around the auditory nerve, which is ton topically organized just as the basilar membrane is). When an electrical current is routed to an intra-cochlear electrode, an electrical field is generated and auditory nerve fibers are stimulated. In the devices manufactured by Cochlear Ltd, two electrodes sit outside the cochlea and acting as grounds-- one is a ball electrode that sits beneath the skin, while the other is a plate on the device. This equates to 24 electrodes in the Cochlear-brand 'nucleus' device, 22 array electrodes within the cochlea and 2 extra-cochlear electrodes.

Speech processors:

Speech processors are the part of the cochlear implant that transforms the sounds picked up by the microphone into electronic signals capable of being transmitted to the internal receiver. The coding strategies programmed by the user's audiologist are stored in the processor, where it codes the sound accordingly. The signal produced by the speech processor is sent through the coil to the internal receiver, where it is picked up by radio signal and sent along the electrode array in the cochlea.

There are primarily two forms of speech processors available. The most common kind is called the "behind-the-ear" processor, or BTE. It is a small processor that is kept worn on the ear, typically together with the microphone. This is the kind of processor used by most adults and older children.

The other form is called a body-worn-processor. This is the kind used typically by younger children, whose ears are too small to properly fit the bulky BTE processor. The body worn processor is kept on the user's body, and a long wire extends up to the microphone earpiece to connect it with the processor. Users of the body worn processor have to find some creative way where to place the body worn processor. Some mothers place the processor on the child's back in a pocket sewn onto a T-shirt or onsite others use a harness that clips across the child's chest.

Programming the speech processor:

The cochlear implant must be programmed individually for each user. The programming is performed by an audiologist trained to work with cochlear implants. The audiologist sets the minimum and maximum current level outputs for each electrode in the array based on the user's reports of loudness. The audiologist also selects the appropriate speech processing strategy and program parameters for the user.

Scientific and technical advances:

Professor Graeme Clark A.C. of La Trobe University, Melbourne, Australia has developed a prototype "hi fi" cochlear implant featuring 50 electrodes. The increased number of electrodes is expected to enable users to perceive music and discern specific voices in noisy rooms.

Researchers at Northwestern University have used infrared light to directly stimulate the neurons in the inner ear of deaf guinea pigs while recording electrical activity in the inferior calicles, an area of the midbrain that acts as a bridge between the inner ear and the auditory cortex. The laser stimulation produced more pre-Cochlear Implants signals in that brain region than the electrical stimulation commonly used in cochlear implants. Laser stimulation is a promising technology for improving the auditory resolution of implants but further research using fiber optics to stimulate the neurons of the inner ear is required before products using the technology can be developed.

Cochlear implants are rarely used in ears that have a functional level of residual hearing. However, Electric Acoustic Stimulation (EAS) devices have been developed that combine a cochlear implant with a sound amplifying hearing aid. EAS devices have the potential to make cochlear implants suitable for many people with partial hearing loss. The sound amplifying component helps users to perceive lower frequency sounds through their residual natural hearing while the cochlear implant allows them to hear middle and higher frequency sounds. The combination enhances speech perception in noisy environments.

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