2002 Conference Proceedings

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Cochlear Implants Are Here to Stay

Presenter:
Sharaine J. Rawlinson, MSW
Materials Development Specialist
Western Region Outreach Center & Consortia
California State University Northridge
18111 Nordhoff Street
Northridge, CA 91330-8267
818-677-2099 Voice/TTY
818-677-6270 Fax
Email: sharaine.rawlinson@csun.edu

Overview

In 1985, the Food and Drug Administration approved cochlear implantation for adults. 1990 brought further approval from the FDA for cochlear implants in children 2 years of age and older. Today, implants can be done in children as young as 12 months and in adults over age 90.

Cochlear Implants are referred to as auditory prosthesis. They are for people who cannot benefit from hearing aids, controversial, available in different models, and a personal choice. This article reviews these issues in part.

How Cochlear Implants Work

Every cochlear implant (CI) is comprised of the following:

Cochlear implants are designed to by-pass cochlear hair cells that are non-functioning and provide direct stimulation to the auditory nerve.

Anatomy of the Ear

Anatomy of the Ear

Cochlea


Cochlea

Image of inner ear.

Determining Candidacy and Implantation

There are several criteria used to determine who is an appropriate cochlear implant candidate. Most importantly, an individual must derive little or no benefit from hearing aids. To receive an implant, individuals must undergo a series of tests.

Implantation is done under general anesthesia and generally surgery takes 1.5 - 5 hours. A 2” square is shaved behind the ear at the temporal bone. A backwards “S” incision (or another type of incision) is made. Then the mastoid bone is opened and the electrode array is inserted into cochlea. When the surgeon is satisfied with the placement of the electrode array, the incision is stitched and bandaged. Recipients are often discharged same day.

Internal Component Entrance to the Cochlea
Internal Component Entrance to the Cochlea


The Electrode Array The Internal Components
The Electrode Array The Internal Components

Recuperation and Hook-Up

Recuperation varies among recipients. Most are back to normal activities within 48 hours. Some individuals require a couple of weeks to regain pre-surgical energy levels. It takes 5-6 weeks for the surgical site to heal.

Once the incision is healed, hook-up takes place. This is when the recipient is fitted with the external devices that include the signal processor, transmitter & microphone. The process of making the equipment work is complicated. How Does A CI Produce Hearing? The microphone picks up sounds and sends them to the processor. The processor then selects and codes sounds that produce useful speech, music, etc. From the processor, sounds are transmitted through the skin to the receiver/stimulator via the magnetic headset. The codes are then converted to electric signals that activate the electrode arrays. The electrodes then stimulate the auditory nerve. The electric signals are recognized by the brain as sounds.

A lot of time is spent “mapping,” that is setting the sound parameters on each electrode at the appropriate, comfortable levels as indicated by the recipient.

The original mapping takes approximately 8 hours. The threshold, ceiling, and mid-range of each electrode are identified by the user in conjunction with an audiologist who is working on a computer. The computer software allows the audiologist to take control of the cochlear implant processor and set the various ranges.

After the initial day of mapping, the user returns to the clinic the next day for re-mapping. This process is repeated at 1 week, 2 weeks, 4 weeks, 8 weeks, 3 months, 6 months, and 9 months. At the end of the first year of use, the recipient returns to their clinic to have their implant evaluated and determine if another mapping is necessary. Follow-ups annually are common, but not required.

Processors

Body Processor Behind the Ear Processor

A: Body Processor

B: Behind the Ear Processor

Two different models are shown:

  1. Body Processor
  2. Behind the Ear Processor

Both models shown here are manufactured by Cochlear Corp. and are used by the author. As stated elsewhere, there are several manufacturers of cochlear implants.

The Controversy Surrounding Cochlear Implants

As stated earlier, there is a tremendous controversy about cochlear implants within the Deaf Community. Previously, the National Association of the Deaf (NAD) took a position that children should not be implanted at all. They have since modified their stand, stating “The NAD recognizes the rights of parents to make informed choices for their deaf and hard of hearing children, respects their choice to use cochlear implants and all other Assistive devices, and strongly supports the development of the whole child and of language and literacy. Parents have the right to know about and understand the various options available, including all factors that might impact development. While there are some successes with implants, success stories should not be over-generalized to every individual.”1

The National Institutes of Health issued a statement on cochlear implants in 1995. It says, in part, “The parents of a deaf child are responsible for deciding whether to elect cochlear implantation. The informed consent process should be used to empower parents in their decision-making. The parents must understand that cochlear implants do not restore normal hearing and that auditory and speech outcomes are highly variable and unpredictable. They must be informed of the advantages, disadvantages, and risks associated with implantation to establish realistic expectations. Furthermore, the importance of long-term rehabilitation to success with cochlear implants must be stressed. As part of the process of informed consent, parents must be told that alternative approaches to habilitation are available. All children should be included in the informed consent process to the extent they are able, as their active participation is crucial to (re)habilitative success.”2

Do adults who receive cochlear implants risk alienation by their deaf friends and colleagues? Absolutely! Given the prevalent pride in being deaf and the additional mis-information about that permeates the field of Deafness, individuals who decide to take the plunge and get a cochlear implant must be braced for inevitable backlash from their colleagues and peers.

Do most doctors ignore cultural aspects of deafness? Most assuredly they do. Strides have already been made, but so much more remains. Doctors must become aware of the subculture of Deafness, the bonds that tie individuals who are deaf together. Rather than backstabbing and complaining about the medical profession, members of the deaf and hard of hearing communities must develop bridges and in-roads into the medical field to create better understanding and respect for deafness and peoples’ choices both to receive and to forego cochlear implantation.

Expectations and Services

What can individuals expect from their cochlear implants? Will their hearing once again function exactly as it had prior to becoming deaf? Cochlear implants will not restore hearing to “normal”. Benefits vary among individuals. Some users only gain knowledge of environmental sound, while others gain ability to use telephone and hear music. Regardless of an individual’s performance with their implant, it is critical that rehabilitation professionals remember that cochlear implants do not make a deaf person hearing!

Following hook-up, many people participate in aural rehabilitation. Aural rehabilitation consists of learning to listen, training the brain to decipher individual sounds, followed by more and more complex sounds as one’s listening skills improve. If the recipient has never heard before, aural habilitation usually requires several hours per week of individual training.

What are the impacts on consumers of Vocational Rehabilitation Services?

What can professionals do for these consumers? Keep in mind that if the consumer uses a form of manual communication, then either the rehabilitation counselor needs to sign with the consumer, or else hire a qualified interpreter (Oral, ASL, PSE). Other services that these consumers request include real-time captioning (CART, C-Print, Typewell, etc.), use of Assistive listening devices (ALDs), and support for psychosocial aspects of their lives. In addition to the aforementioned, it is important for the rehabilitation professional to remember the following about their consumers who are users of cochlear implants:

1National Association of the Deaf, Position Statement on Cochlear Implants, October 6, 2000.

2Cochlear Implants in Adults and Children. NIH Consensus Statement Online 1995 May 15-17 [cited 2001 September 28]; 13(2):1-30.


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