Download Annotated Bibliography

Annotated Bibliography
"Animation: Normal Ear, Ear with Hearing Loss, and Cochlear Implant Procedure."Medical
Devices. FDA, 23 Sept. 2011. Web. 19 Mar. 2013.
This animation on the FDA’s website leads us through the workings of a normal ear,
then an ear with hearing loss, and finally the cochlear implant procedure. The first
diagram shows the outer, middle, and inner ear with all of the internal and external
implant components in place. It then switches to an animation of what a normally
functioning ear looks like. The animation moves to show a similar ear, but with less
sound transmitted from the outer ear to the auditory nerve due to hearing loss. Then the
animation leads us step by step through the surgery and adjustment of a cochlear implant
as it is inserted. Finally, the animation shows how the working cochlear implant operates,
with the microphone converting the sound wave to an electrical signal, which travels
along a wire through a hole in the cochlea to stimulate the nerve to the brain. The
incredible detail and images of this animation make the process so clear that our
audience will likely find it enormously helpful.
"Cochlear Implants." ASHA.org. American Speech-Language-Hearing Association, 2013. Web.
19 Mar. 2013.
The American Speech-Language-Hearing Association’s article on cochlear implants
provides an excellent and very helpful, well-organized overview of cochlear implants.
The article is divided into five sections: what cochlear implants are, how they work,
where one can go to get one, what is involved in the process of getting one, and who is
best suited for them. The practicality of this article is enormously helpful because the
information is written clearly for lay people. The article defines a cochlear implant as a
“device that provides direct electrical stimulation to the auditory nerve in the inner ear.”
It explains the external and internal parts of the implant, and describes the cochlear
implant centers around the country where people can undergo the process. It outlines the
process of testing and surgery involved in getting the implant, and finally it lists the
characteristics of adult and child patients that make them suitable for the device.
"Cochlear Implant Information." Johns Hopkins Medicine. The Johns Hopkins University, The
Johns Hopkins Hospital, and Johns Hopkins Health System, n.d. Web. 21 Apr. 2013.
John Hopkins offers information on how cochlear implant enable hearing. Sounds are
coded with the speech processor the programming of which selects the important features
of incoming sounds transmitted to the brain. These codes a presented through channels in
the electrode array, allowing a user to perceive pitches. Power and tempo (or loudness) of
the sounds are conveyed through patterns in the impulses. Cochlear implants do increase
spoken communication and perception of environmental sounds. To realize the full
potential of cochlear implants, early implantation is best, and must be paired with precise
programming and communication training. The site also gives information about natural
hearing, candidates for cochlear implants, the surgery, programming, and a specific
section on implantation in young children. For cochlear implants to work well in children,
they should be implemented early. Children will also need extensive rehabilitation to give
meaning to sounds and support from their families and professionals around them to gain
sophisticated communication skills. Rehabilitation with pathologists and deaf educators is
key to success with cochlear implants. Training encourages detection and imitation skills
necessary for oral language development.
"Cochlear Implants." National Institute on Deafness and Other Communication Disorders.
National Institute of Health, Mar. 2011. Web. 18 Mar. 2013.
Cochlear implants result in successful speech perception in children. Currently, the
earliest age of implantation is 24 months, but there are reasons to reassess this age limit.
Implantation at a younger age may limit the negative consequences of auditory
deprivation and allow more efficient acquisition of speech and language. Determining
whether cochlear implant benefits are greater in children implanted at age 2-3 compared
with those implanted at age 4-5 might resolve this issue, but sufficient data are
unavailable. Also, it is unclear whether the benefits of implantation before age two
would offset potential liabilities. A small number of children under age 2 have received
implants, both internationally and in the United States. Cochlear implants principally
have been performed in this population because of the risk of new bone formation
associated with meningitis, which might preclude implantation at a later date. Speech
and language data obtained on such children will be helpful in determining the potential
benefits of early implantation and therefore may help to guide future policy.
"How Does a Cochlear Implant Work?" Cochlear Implant Online. Cochlear Implant Online,
2012. Web. 19 Mar. 2013.
Basically, there are three sections work together to deliver sound to the brain. In normal
hearing the outer ear picks up sound and sends the sound waves down the ear canal to
the eardrum. These sound waves cause the eardrum to vibrate, in turn causing the tiny
hair cells inside the cochlea to move. The hair cells absorb the movement and change it
into electric impulses which are sent to the hearing nerve fibers of the brain. The brain
interprets these impulses as sound. Technically, cochlear implant have two parts; an
internal part and the external part including the speech processor. Sounds enter the
speech processor through a microphone, and the process converts them into digital
signals. The digital signals travel through the coil transmitter and are then sent through
the skin to the receiver part of the internal implant. The receiver changes the signal into
electrical energy which is sent along an electrode array that is connected to the cochlea.
The electrical impulses stimulate the auditory nerve, bypassing the damaged hair cells.
As with natural hearing, the brain interprets the simulation as sound.
Hyde, Merv, and Des Power. "Some Ethical Dimensions of Cochlear Implantation for Deaf
Children and Their Families." Journal of Deaf Studies and Deaf Education Winter 11.1
(2006): 102-111.
This article, instead of illustrating the cochlear implants itself, offers a comprehensive
overview of the social controversy over the technology. Its discussion sheds light on a
more appropriate application of cochlear implants to children from broader backgrounds.
Implantation in young deaf children gives rise to controversy concerning ethnic issues
between people that perceive deafness as curable disability and those who do not see
deafness as a condition that needs to be fixed. The implantation decision not only
involves many ethical considerations such as informed consent, risk-benefit
determination, and children’s right, but also impacts the personal, social, communal, and
cultural lives of implantees and their families. However, the access to this technology
and related information is not equally available to families. Access depends on
socioeconomic status and race. More studies on how these factors affect outcomes of the
technology should be conducted. Meanwhile, the inequality problem should be
addressed by public agencies so more individuals and families suffering from deafness
can learn about their choices.
"Inside a Cochlear Implant Surgery." Cochlear Implant Online. Cochlear Implant Online, 8 Apr.
2008. Web. 19 Mar. 2013.
There are several myths about cochlear implant surgery, which misleads those
individuals and families who considering receiving the device and prevents them from
making an informed decision. The author of the article, who got an opportunity to
witness a cochlear implant surgery on the spot, wrote about her experience and corrected
four of the typical misunderstandings. The surgery is often perceived as a dangerous
operation that makes a hole in the skull with the potential possibility to paralyze facial
nerves and get meningitis afterwards. This intimidating description is not accurate at all,
according to the author, since the actual surgery only involves a small incision and
bleeding as well as limited chances to endure the negative aftermaths.This article helps
to correct the popular bias against the cochlear implant surgery. With its objective
description of and attitude towards the surgery, people are able make a more reasonable
choice by weighing the risks and benefits.
Kral, Andrej, and Gerard M. O'Donoghue. "Profound Deafness in Childhood." New England
Journal of Medicine 363.15 (2010): 1438-450.
Childhood deafness affects more than just an individual’s ability to hear sounds. Kral
and O’Donoghue examine the other medical ramifications of childhood deafness in this
article. Recognizing or differentiating sound is part of a child’s process in learning how
to abstract and categorize stimuli. These perceptual objects are formed in the cerebral
cortex, which is also responsible for conscious experience and sensory learning, and it
continues developing until adulthood. Deafness, therefore, impair cortical development
because it fundamentally alters the auditory system. If this system does not develop as a
child, complex auditory functions and speech perception cannot be comprehensively
established late in life. “The acquisition of spoken language requires auditory input and
interaction with the environment.” Additionally, when teaching children who are deaf,
information that is typically represented through sound is represented in other forms.
This change in representation can have adverse cognitive effects, including the ability to
scan and retrieve phonological and lexical information. Cochlear implants, therefore,
should be considered only for children who still have auditory plasticity.
Sharma, Anu, Michael F. Dorman, and Anthony J. Spahr. "A Sensitive Period for the
Development of the Central Auditory System in Children with Cochlear Implants:
Implications for Age of Implantation." Ear and Hearing 23.6 (2002): 532-39.
Sharma, Dorman, and Spahr examine the consequences of receiving cochlear implants at
different ages during childhood. A central issue when discussing pediatric cochlear
implants is finding the ideal age for the implant. The common belief is that an individual
will have better results at an early age rather than later in childhood because absence of
sound causes degeneration of the central auditory system. The authors compared the P1
latency of naturally hearing subjects ranging from .1 to 20 years of age to those of
children with cochlear implants at ages ranging from 1.3 to 17.5 years old. From these
data they were able to create a range of “normal” latency. They found that those who
received the cochlear implants at an early age were within this range, whereas those that
receive it later in life fell outside the range. Being inside this range, however, was not an
instantaneous result of the implant. “As a group, congenitally deaf children implanted
under 3.5 yr of age demonstrated age appropriate P1 latencies by 6 mo postimplantation.”
The time period before a child reaches approximately 3.5 years old is a period in which
the auditory system is plastic enough to develop at normal levels post implant.
"Single Channel versus Multi-Channel Cochlear Implants." HealthyHearing.com. Healthy
Hearing, n.d. Web. 21 Apr. 2013.
This website offers explanations on how multichannel cochlear implants offer more
accurate information about sounds for the user. The number of channels is connected to
the number contacts between the electrode array and the inner ear. Each of these
simulation sites represent a pitch or frequency of sound. Incoming sounds are separate
along these channels to convey a differences. Understanding and explaining multichannel
demonstrates the the advances in technology. Cochlear implants were single channel
devices when they were first used. Multichannel cochlear implants increase an
individual’s ability to understand speech because of the differentiation in pitches and
frequencies. People who have received cochlear implants more recently demonstrate
better oral communication skills, particularly those involved with recognizing someone
else’s speech.
Svirsky, Mario A., Amy M. Robbins, Karen Iler Kirk, David B. Pisoni, and Richard T.
Miyamoto. "Language Development in Profoundly Deaf Children with Cochlear
Implants." Psychological Science 11.2 (2000): 153-58.
Mario Svirsky et al. examine the effects of childhood deafness on the language
developments. Deafness at a young age dramatically affects a child's’ ability to develop
language. They learn communication skills at a rate far slower than natural-hearing
children, as a result of a delay in their learning. Natural-hearing children begin learning
language the moment they are born because they can hear sounds. Children who are deaf
have a harder time acquiring language because there is a delay in their learning. Svirsky
and his colleagues also examine the difference between children with cochlear implants
and those who are deaf but did not receive the device. Those with the implant exceed the
rate of language development of unimplanted children who are deaf. Their rates are much
closer to natural-hearing children. Oral language is especially learned through the
auditory input from the cochlear implants.
Wilson, Blake S. "Engineering Designs of Cochlear Implants." Cochlear Implants: Auditory
Prostheses and Electric Hearing. New York: Springer-Verlag, 2004. N. pag. Google
Books. Google. Web. 19 Apr. 2013.
Blake Wilson provides a very detailed, scientific explanation of cochlear implants,
especially the behind-the-ear (BTE) housing. Though it was written in the early 2000s
and therefore is almost a decade out of date, the technology works in basically the same
manner. Cochlear implants consist of the same major components now as they did ten
years ago; microphone, speech processor, transmitter, receiver, and an electrode array. A
huge difference in the devices is that the speech processor is now housed with the rest of
the BTE components, instead of a separate unit. These ability was just emerging in the
early 2000s due to the same technology used in cell phones. Wilson also discusses the
placement of the electrode array. It is important to connected it along several points of the
cochlear to simulate the nerve. This chapter is helpful in understanding the science and
technology development behind cochlear implants.