HLAA Position Paper on CIs - Part One

Editor: Here's a CI position paper on cochlear implants (CIs) from the Hearing Loss Association of America (HLAA). It contains some great information on a variety of CI issues, and is reprinted with permission from the Hearing Loss Association of America, www.hearingloss.org.

This is part one of two parts.

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June 2007

Cochlear implants (CI) are designed to provide a person access to acoustic information while completely bypassing the normal route of sound transmission to the cochlea. They accomplish this by directly activating the nerve fibers normally stimulated by sounds traveling through the middle ear and into the cochlea.

Cochlear implants are intended for people whose natural hearing, even under optimal hearing aid conditions, provides less functional auditory capabilities than what is generally achievable through an implant.

Cochlear Implant Advances

The first cochlear implants were single channel devices that could convey only the most basic of auditory dimensions, i.e. the presence or absence of sound and some varied loudness sensations. In spite of their limitations, many people, particularly late-deafened adults, found that a cochlear implant could be very helpful. With an implant, users could hear and differentiate between some environmental sounds.

Speechreading skills were enhanced because of the additional auditory information, and more effective vocal monitoring of one's own speech was now possible. During this period, implants were not generally considered a viable possibility for pre-lingually deaf children or adults.

Since that era, and at the time of this writing in 2007, the technical advances in cochlear implants have been rapid and noteworthy. These advances reflect contemporary scientific accomplishments in electronics and microprocessors as well as an increasing depth of knowledge in auditory physiology. The current generation of implants has benefited from these developments and are fully capable of permitting many, if not most, users to understand speech solely through hearing. Improvements in the hardware have been accompanied by parallel developments in speech processing algorithms.

Additionally, there are ongoing research programs in countries all around the world devoted to further increasing the effectiveness of cochlear implants in both the hardware and software. Other research studies are focused on the actual listening performance of implant users over extended periods of time, as well as examining and comparing the results of newly introduced speech processing strategies and devices. In short, there is no doubt but that cochlear implants devices are well grounded scientifically; they no longer can be considered experimental or unproven devices. Thus, they have taken their place in the armamentarium of aural rehabilitation devices routinely available for people with hearing loss.

Realistic Expectations

It should be clearly understood, however, that even under the best of circumstances a cochlear implant cannot, and does not, replace the natural auditory structures and normal physiology, A cochlear implant is not an "ear replacement." Anybody considering an implant, for themselves or their children, will be disappointed if they enter the process with this expectation in mind.

What implants can and have done is permit acceptable auditory functionality in many situations and for many purposes (oral communication, telephone conversations, auditory-verbal development, etc.). The CI can permit a user to move from a functional deaf category, with all that this implies, to one who is able to function as a hard of hearing individual. In real-life this can make an immense difference.

Three Groups of Potential Candidates

Late-Deafened Adults

There are three general groups who are potential candidates for a cochlear implant.

The first, and largest group are late-deafened adults, those who grew up with normal auditory capacities but who later developed a severe to total bilateral hearing loss. This is a group that is fully aware of how the loss of hearing has impacted upon the totality of their lives (social, cultural, economic, etc.). It is also the group that has the best prognosis because they have a lifetime experience with sound (either naturally or through hearing aids) and thus the sound sensations received via an implant can benefit from intact auditory memories.

As adults, this group is ultimately responsible for making for themselves the decision whether or not to acquire an implant. Hearing Loss Association of America (HLAA) strongly advises, however, that the decision to acquire a cochlear implant be made only after consultation with the professionals in a cochlear implant center. It is their responsibility to review the possibilities and limitations of cochlear implants for specific individuals. Then, armed with this information, potential implant candidates can make a more informed decision. .

Pre-Lingual or Adults with Long-Standing Hearing Loss

The second general group is also composed of adults, but those with pre-lingual or extremely long-standing hearing losses. This is a group that has not employed sound as their primary communication channel. On the contrary, they employ some visual form of communication, either sign language or speechreading, for this purpose.

Because of the potential consequences of long-term auditory sensory deprivation, their prognosis is more guarded than the first group. Their auditory memory is essentially absent or extremely limited and they may display some degree of neural atrophy in portions of the eighth nerve. Nevertheless, many people in this group have also opted to acquire a cochlear implant.

Generally, while not as dramatic as is often found in the late deafened group, adults in this category have also made significant progress in auditory awareness and speech perception. Further, the evidence suggests that slow, but steady auditory-verbal progress can continue to be made over the years for people who fall into this general category. As adults, they are also ultimately responsible for making their own decision regarding the acquisition of a cochlear implant.

As with the first group (late-deafened adults), HLAA recommends that adults falling into this category consult with the professionals in a cochlear implant center before making a final decision.

Here's Part Two

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Updated: June 1, 2007