| Cochlear Implants And Hearing Essay, Research Paper
Introduction:
I decided to do a researched-based project. Since I was a young child I have
been fascinated by the Hearing Impaired. Recently there has been much
controversy in the Deaf community over the use of Cochlear Implants in pre-lingual
deaf children. I took this assignment as an opportunity to take a closer look into the
world of hearing aids and Cochlear Implants. Since I was in high school I have
known what I wanted to do with my life: Work with the hearing impaired to better
their communication skills. In order for me to fulfill my goals, it is important for me
to fully understand the devices out there that may or may not help a deaf patient
hear the slightest sound. There has been much controversy, as noted before,
because of the advanced use of the Cochlear Implant, in fact many members of the
Deaf community view it as an effort of the hearing world to fix the deaf world.
Many Deaf people do not wish to be fixed, nor do they feel anything is wrong with
them. I wanted to research this so I would be better equipped to make an educated
opinion of my own about the intentions of the Cochlear Implants being used in
pre-lingual children.
Findings:
I feel it important to start with the basic anatomy of the normal working ear.
Without knowledge of the basic concepts and terms of hearing the rest of the
findings will be rather confusing. First lets cover some key terms. An Audiologist is
a person with a degree and/or certification in the areas of identification and
measurement of hearing impairments and rehabilitation of those with hearing
problems (Turkington). The oval window is the tiney opening at the entrance of
the ear. There are three basic parts of the ear that will be covered in detail shortly:
the outer ear, the middle ear, and the inner ear. The middle ear is the small cavity
between the eardrum and the oval window that is home to the three tiney bones of
hearing. The eardrum is a paper thin covering that stretches across the ear canal,
separating the middle ear from the outer ear. The inner ear is the inside section of
the ear where sound vibrations are formed into messages that are sent to the brain.
Hair cells facilitate this because they are the tiney sensory receptors that transform
the messages to the brain. (Turkington) The ear as a whole is pictured below in
figure 1, and the three sections of the ear are explained in more detail:
Figure 1:
The human ear is divided into three anatomical divisions; the outer ear
which includes the pinnae or auricle and the external auditory canal; the
middle ear which includes the tympanic membrane (the ear drum) , the
middle ear ossicles (bones) named the malleus (hammer), the incus (anvil)
and the stapes (stirrup), as well as the cavity in which they are situated (otic
capsule); and the inner ear which includes the cochlea and the semicircular
canals. (Anatomy…)
Hearing aids are the age old remedy to hearing loss in varying degrees. A
hearing aid is a device that amplifies sound waves to help sounds be processed more
clearly. Hearing aides amplify sounds, helping a person hear better, but cannot
restore normal hearing abilities. Hearing aids will amplify ALL sounds, not just
those that the person wishes to hear. This results in much interference, which can
take some getting used to. (Turkington)
There are many types of hearing aids available, more than 1,000 different
models are available in the United States alone! Each type will include a
microphone to pick up the sounds, an amplifier to boost the sound level, a receiver
or a speaker to deliver the sound to the ear, and all are powered by some sort of
battery. Some people wear them in just one ear (monaural) or can wear them in
both ears (binaural). Hearing aids are divided into five different types: digital,
in-the-ear, in-the-canal, behind-the-ear, and on-the-body. The two most common
are in-the-ear and behind-the-ear models, shown in figure 2. (Turkington)
Figure 2
In-the-ear aids are lightweight devices whose custom-made housings
contain all the components; this device fits into the ear canal with no visible
wires or tubes. It is possible to control the tone but not the volume with these
aids, so they are helpful only for people with mild hearing loss….Because they
are custom-fit to a person s ear, it is not possible to try on before ordering.
Behind-the-ear aids include a microphone, amplifier and receiver
inside a small curved care worn behind the ear; the case is connected to the
earmold by a short plastic tube. The earmold extends into the ear canal.
Some models have both tone and volume control…. some people who wear
glasses find that the glasses interfere with the aid s fit. Others do not have
space behind the ear for the mold to fit comfortably. (Turkington)
The First step in preparing for a hearing aid is to have a medical exam and a
hearing evaluation. Through this exam, and audiologist can determine whether or
not a hearing aid will help, and which model will be the most beneficial. Hearing
aids can be very expensive, anywhere between $500 and $4,000, and are usually not
covered by most insurance plans. There is no known medical risk to hearing aids,
although some people choose not to wear them sometimes, complaining that
everything seems entirely too loud. (This is often due to the fact that the person has
forgotten how loud normal sound can be.) (Turkington)
Cochlear Implants are beneficial in restoring hearing in a profoundly deaf
patient whom cannot be helped by a conventional hearing aid. According to a
report of surgical results… the device is capable of restoring speech discrimination to
the extent that patients can once again carry on a conversation (Parkin) The
Cochlear Implant acts as an artificial human cochlea in the ear, aiding sound travel
from the ear to the brain. It is different from a hearing aid in that it does not
amplify the sound, it merely helps it to travel. Cochlear Implants are electronic
prostheses that transduce sound energy into coded electrical signals that bypass the
nonfunctioning or absent Cochlear hair cells and deliver them directly to the spinal
ganglion cells or axons of the Cochlear nerve. Proximal neural elements conduct
these impulses to the auditory cortex, thereby restoring the sensation of hearing.
(Callanan)
The Food and Drug Administration (FDA) has placed limits on those people
eligible for the Cochlear Implants. They have done this because they are highly
controversial, very expensive, and sometimes have uncertain results. ( The cost of
surgery ranges from $7,000 to $10,000, and the price of the device is about $10,000.-
Parkin) Only those people who receive no significant benefit from hearing aids, are
atleast two years old, and have severe to profound hearing loss are eligible. A
typical Cochlear implant is pictured in figure 3.
Figure 3
All Cochlear implants consist of a microphone worn behind the ear
that picks up sound and sends it along a wore to a speech processor, which is
worn in a small shoulder pouch, pocket, or belt. The processor boosts the
sound, filters out background noise, and turns sound into digital signals
before sending it to a transmitter worn behind the ear. A magnet holds the
transmitter in place through its attraction to the receiver-stimulator, a part
of the device that is surgically attached beneath the skin in the skull. The
receiver picks up digital signs forwarded by the transmitter, and converts
them into electrical impulses. These flow through electrodes contained in a
narrow, flexible tube that had been threaded into the cochlea.
As many as 24 electrodes (depending on the type of implant) carry the
impulses that stimulate the hearing nerve. The brain then interprets the
signals as specific sounds. (Turkington)
Despite all the possible benefits of this procedure, many members of the Deaf
community argue that the benefits do not outweigh the risks and limitations of the
device. They are also concerned that this Implant will have the potential to make
their language, American Sign Language, obsolete. Because it is a surgical
procedure, medical risks are possible, such as dizziness, facial paralysis, or infection.
During the procedure, the surgeon will make an incision behind the ear to open the
mastoid bone that leads to the inner ear. The receiver-stimulator is placed in the
bone, and the electrodes are threaded into the cochlea. The operation can take
anywhere from one hour to five. It is impossible to guarantee a significant change in
hearing abilities. Many people describe the sounds they are able to hear as being
robot-like or artificial. This of course is a result of no medical breakthrough being
able to match the ability of a persons natural hair cells to transport sound to the
brain. (Turkington)
Most people whom receive the implant report being able to distinguish
medium to loud sounds, especially speech. Vincent Callanan reports that
Postoperative speech perception varies widely, although patients can be simply
classified as good or poor responders. Factors predictive of better performance,
irrespective of the device implanted, include younger age at the time of
implantation, a higher IQ, a normal cochlea on computed tomographic scan, and
better ability to lip-read.
The problem arises when Cochlear implants are used in children that are
prelingually deaf: those children that have not yet developed any meaningful
acquisition of oral language. Robert Crouch argues that the Cochlear implant is
intended to help the deaf child ultimately learn an oral language and, in doing so, to
facilitate the assimilation of the implant — using the child into the mainstream
hearing culture. When the child receives a Cochlear implant, he or she is put on a
lifelong course of education and habilitation, the focus of which is the acquisition of
an oral language, and ultimately, a meaningful engagement with the hearing world.
He does not argue that this is a horrible thing, however if the parents make the
decision to fix the child s deafness before he really understands it, the child is
separated from a part of their lives, their DEAFNESS. It is important that the child
be able to experience their true identity, and later in life, when the child is mature
enough and comfortable with themselves, it is then that the decision should be made
to receive the implants.
Crouch sums up his argument against Cochlear implants, saying While the
postlingually deafened person, once fitted with a Cochlear implant, can maintain his
or her present speech production capabilities and relearn to hear, the prelingually
deaf child using a Cochlear implant must be intensively taught and trained to
recognize and produce each vowel and consonant sound and each word from the
ground up. For the implant using prelingually deaf child, then, the path to oral
language development is a long and arduous one beset with many pitfalls, where
there seems to be no guarantee that the destination will be reached. Why put a
child through this with no real guarantees? Would it not be better to wait until the
child has developed enough to be emotionally stable and secure with themselves?
A child that is permitted to remain deaf can look forward to learning a
language as unique as their condition: ASL. Through this the child will have a
building block to learning and recognizing spoken language. They will share a
culture with people similar to themselves, and will be able to make a choice between
hearing and remaining deaf. I firmly believe that the battle of going from deaf to
hearing is a long and trying one, and the person should be old enough to understand
that before making the decision.
Conclusion:
I can understand how the prospect of the Cochlear Implants can appear to
be a light at the end of the tunnel for those parents who foster deaf offspring.
However, I do feel it to be very important to allow the child to first experience their
own culture before forcing the hearing world on them. The world of the deaf person
is rich with culture and history, believe it or not, and I believe that it would be easy
for a prelingual child to feel stuck between two worlds: the hearing and the deaf.
The child could very easily feel as if they belong to neither group. The decision to
use any type of hearing device, whether it be a hearing aid or a Cochlear implant,
should be the decision of the individual, when they are mature enough to
understand all the benefits, risks, and complications.
References:
Anatomy of the Ear
April 20, 2001.
(also source of Figure 1)
Callanan, Vincent. Cochlear Implantation for Children and Adults.
Lancet. 2000; 356(8999): 412-414. February 17, 1996.
Crouch, Robert A. Letting the deaf be deaf: reconsidering the use of
Cochlear implants in prelingually deaf children. The Hastings
Center Report, July- August. 1997. v27. n4. p14(18).
Larkin, Marilynn. Can lost hearing be restored? Lancet. 2000;
356 (9231): 744. August 26, 2000.
Parkin, M.D., James L. Multichannel Cochlear Implant Restores Hearing.
Am Fam Physician 1984; 30 (5): 249. November, 1984.
Turkington, Carol A. Cochlear Implants. Gale Encyclopedia of Medicine.
Edition 1. 1999. p740.
(also the source of figure 3)
Turkington, Carol A. Hearing Aids. Gale Encyclopedia of Medicine.
Edition 1. 1999. p1354.
(also the source of figure 2)
|