This article appeared in the July/August 2002 issue of Hearing Loss: the Journal of Self Help for Hard of Hearing People.

Cochlear Implant Candidacy and Outcomes: 2002 Update

By Donna L. Sorkin

Regardless of whether you have considered a cochlear implant (CI) in the past but were determined to have “too much hearing,” or you disqualified yourself thinking that CI’s are only for those who are completely deaf, you may want to take a second look at where we are today with this extraordinary technology. There have been important changes in recent years—both in outcomes and candidacy criteria.

Cochlear implants are now better than ever before—making CI’s an appropriate choice for greater numbers of adults and children with hearing loss. With three manufacturers, all producing excellent products, the decision for candidates now is often not so much whether to go forward as much as which product to select.

Age has nothing to do with candidacy or outcomes for a cochlear implant. Children as young as 12 months and adults age 80 and older routinely receive cochlear implants. In 2002, most children with cochlear implants attended school in mainstream settings using spoken language as their communication mode. A decade ago, a high proportion of deaf children would have been placed in a separate educational facility, such as a school for deaf children. Now, with more children using spoken language approaches for communicating as well as greater efforts by public schools to address the needs of all deaf and hard of hearing children—regardless of modality—parents increasingly opt for less restrictive environments for their deaf children.

Cochlear implants have been demonstrated to have a significant, positive impact on the health and general quality of life of seniors with significant hearing loss. For seniors living alone or for those with poor vision, the restoration of hearing provided by a cochlear implant is critical to one’s ability to live independently. The isolation that often accompanies significant hearing loss is mitigated or even eliminated as cochlear implant users once again enjoy social, cultural or educational activities that may have become inaccessible to them. For the appropriate candidate, a cochlear implant often provides dramatic listening improvements for those who are already using hearing aids and assistive listening devices but still struggle to understand speech.

Expanded Candidacy Criteria

When I received my cochlear implant in 1992, appropriate adult candidates were those who: (1) lost their hearing after acquiring language (postlinguistic), (2) had a profound hearing loss, and (3) demonstrated little or no open-set sentence discrimination. I fit the criteria perfectly as I derived minimal benefit from hearing aids and was receiving nearly all of my speech information from a speaker’s lips. Functioning in a group situation or anywhere in which I didn’t have ideal lighting was always challenging. Indeed, I was exhausted after any group interaction from the amount of effort that I needed to put into listening and watching. Having observed many SHHH members derive enormous benefit from a cochlear implant, it was an easy decision for me to pursue this option once my implant team at Johns Hopkins Hospital made the determination that I was an appropriate candidate.

“Recipients May Now Have More Residual Hearing”

Candidacy decision-making for cochlear implants has changed in important ways since the early 1990s when I had my surgery. Now, adults and children may have more hearing and better outcomes with hearing aids. Specifically, the level of hearing loss has been expanded from profound deafness to include individuals with a severe to profound hearing loss, opening up the benefits of cochlear implants to many more deaf and hard of hearing people. Speech understanding for adults can be as high as 50 percent (with a hearing aid) in the ear to be implanted, or 60 percent (with hearing aids) binaurally. Individuals with such listening scores would have been turned down for a cochlear implant in the past for having too much hearing.

I often meet people who explored their candidacy some years ago but were rejected because their sentence discrimination scores exceeded the thresholds at the time they were evaluated. Such rejection often causes frustration for the person seeking an implant as he or she watches cochlear implant users with less residual hearing than the CI candidate readily participating in listening situations that they consider overly difficult. With today’s expanded candidacy criteria, many such individuals would now be considered appropriate candidates for a cochlear implant. Having been rejected once for “too much hearing,” sometimes people question why an implant would be appropriate now and not before. Or, sometimes those who are close to the thresholds are fearful about “losing the hearing that they already have” [in the implanted ear].

The decision as to whether to go forward is a personal one that should feel right for each individual, regardless of the results of their objective candidacy evaluation. At the same time, potential recipients should rest assured that if they are evaluated and determined to meet the candidacy criteria, the benefits gained via the cochlear implant will improve their hearing capabilities beyond what they derive from their hearing aid(s). It would be unusual for such improvement not to occur.

“Prelinguistic Deaf Adults Now Candidates”

Another important change in candidacy decision-making in recent years is the inclusion of prelingually deafened adults, individuals who were either born deaf or lost their hearing prior to learning language, as appropriate candidates for a cochlear implant. Until recently, adults who had been deafened in early childhood were not considered good candidates for a cochlear implant. Recently, an increasing number of prelingually deafened adults who have used amplification, listening, and speech for an early and significant portion of their lives have received cochlear implants with excellent results. Indeed, there are many such members of SHHH who have had a significant hearing loss from early childhood and who consider themselves to be hard of hearing because they maximize use of their residual hearing with hearing aids and assistive listening devices but who nonetheless would gain important benefits from a cochlear implant.

Some successful cochlear implant recipients (who have had hearing loss from childhood) use sign language in conjunction with listening while others rely entirely on spoken language. The key success factor for this group of adults is being “wired for sound” by having used the auditory channel with amplification for some period of their lives and also being comfortable with spoken language. A number of such individuals who received cochlear implants are now able to use a voice telephone when they had neverdone so before. Not all prelingually deafened individuals who receive cochlear implants gain sufficient open set discrimination to use a voice telephone, but most appropriate candidates do derive valuable listening improvements for spoken language and environmental sounds as well as improved ability to monitor their own speech.

“Younger Children = Better Outcomes”

Another major change is the expanded use of cochlear implants for young children. In 2001, 65 percent of newborn babies were screened for hearing loss prior to leaving the hospital as part of universal newborn hearing screening programs. Early identification of hearing loss has allowed children who are identified and receive appropriate intervention by six months of age to attain significantly better language skills than those whose losses are addressed after six months of age (Yoshinaga-Itano et al, 1998). With so many children being identified in the first days of life, it is no longer unusual to fit babies as young as one month with hearing aids. Such early fitting gives these children a valuable jump on learning language and also provides the basis for the earliest possible evaluation of their candidacy for a cochlear implant.

Early identification, along with expanded trial criteria and commercial indications, have made possible a dramatic lowering in the age of implantation of children. In 1997 in the United States, a total of 8 children, 18 months or younger received a cochlear implant compared with 125 children under 18 months in 2000. Predictabley, the numbers of young children 18 months and younger receiving a cochlear implant in 2001 will demonstrate a striking increase over 2000. There is a trend towards earlier implantation in children as well as more rapid growth in pediatric implants compared with use of the technology in adults.

The Food and Drug Administration (FDA) criteria now include as appropriate candidates children as young as 12 months, if the child has a profound hearing loss and demonstrates a lack of auditory progress with appropriate amplification. We are now routinely implanting children at 12 months of age; less than a decade ago, a two-year-old was considered a very “young” candidate. The FDA guidelines now include children with a severe to profound loss at two years of age.

For a child of any age, the entire family must be highly motivated to pursue the needed habilitation. A cochlear implant is not magic and successful outcomes require hard work and a serious commitment from everyone involved in a child’s life -- the child, her siblings and parents, grandparents, other caregivers, friends, and teachers.

Improved Outcomes with Cochlear Implants

Cochlear implant technology has advanced dramatically, improving outcomes for both adults and children. A key reason for the (above discussed) expanded candidacy criteria is the fact that results with cochlear implants have improved so significantly. We know, for example, that someone who is currently able to understand 50 percent of words in sentences wearing appropriate amplification, will likely enjoy much improved speech understanding with a cochlear implant. Because cochlear implant outcomes have improved over time, the candidacy requirements have been lowered.

There is now a considerable body of experience and data, confirming performance levels for cochlear implant recipients of all ages. With each enhancement in the device design, the speech coding strategies, and/or the mapping techniques used by cochlear implant audiologists to program the device, we’ve seen users’ speech recognition scores continue to improve. The chart, “Mean Recognition Scores 1981-2001” illustrates the impact that advances have had on adult performance with a cochlear implant.

On a personal level, I have first-hand experience with the impact that such improvements can have on an individual user’s performance. I received my cochlear implant in 1992 and initially used the MSP speech processor, which was programmed using a speech coding strategy called MPEAK. My sentence discrimination scores after one year were 65 percent in quiet (without speechreading), up from 4 percent prior to receiving my cochlear implant. (The average score for an adult MSP user was 58 percent, as shown below.)

This was a dramatic change for me—one that made an almost unimaginable difference in my ability to understand speech. Right away, my speechreading skills improved and I found that I was less tired. Stress levels associated with difficult listening situations declined dramatically—indeed, my hearing improved beyond my expectations. My family and friends all noticed how much easier it was for me to interact with groups of people. Indeed, my mother cried the first time we had a conversation after my cochlear implant was activated; she was overwhelmed by how much easier it was for me to carry on a conversation. Within six months I had regained some use of a voice telephone—which I had not used at all in some years.

You can imagine my joy when further improvements resulted in an upgraded speech processor that improved performance even more. In 1994, I received the Spectra body-worn speech processor, which used a new speech coding strategy (SPEAK). Because it was considered an upgraded device, my health insurance covered the new speech processor. No surgery was needed—I simply plugged it in and enjoyed the rapid improvements in performance. Within two weeks, my ability to use the telephone went from being able to talk to familiar people on well-defined topics to nearly unlimited use of the telephone. When I was next tested at my cochlear implant center, my sentence discrimination scores in quiet had jumped to 99 percent.

Adult cochlear implant recipients with at least six months of experience using the most advanced technology on the market now have average sentence discrimination scores of 90 percent. By definition, an average means some scores are higher and some are lower. Such scores are typical of performance across the industry for appropriate adult recipients using current technology.

Typical outcomes for children are more variable. Children implanted prior to 18 months of age who have received appropriate habilitation, strong family support, and school placement in an oral program tend to perform the best. Children continue to demonstrate improvements in listening over a period of three to five years, sometimes even longer. It is not usual for children who have been implanted early and given the best possible support to achieve listening outcomes comparable to those of adults. Other important measures of language development (i.e., speech production, reading, vocabulary) associated with cochlear implants in children have been well documented.

Convenient Refinements: Ear Level Processors, Programs for Noise, Color, and Telecoils

Cochlear implant manufacturers are now working on all manner of refinements to make their technology attractive, convenient, and compatible with a range of assistive listening devices. All three of the manufacturers offer ear level devices that perform comparably with the traditional (box-like) body-worn processors. Some of these look much like a behind-the-ear hearing aid. Taking a cue from the hearing aid industry, cochlear implants are now offered in a range of skin tones (i.e., beige, black, brown) and even sleek silver! Some companies offer removable battery covers in wide-ranging colors—purple, cobalt blue, pink, green, and yellow. Needless to say, children love the color options. Manufacturers offer a means of connecting to assistive devices, televisions, radios, CD’s, and of course telephones. One manufacturer recently added a telecoil to their device allowing direct linkage to telephones with the flick of a switch. Directional microphones, special settings for soft voices, and programs designed for noisy environments are other features that stretch users’ ability to hear in difficult listening situations.

It is extraordinary to realize that multi-channel cochlear implants have been in existence just a little more than 20 years. More extraordinary still is the rapid manner in which they have improved and the magnitude of hearing benefit provided by today’s devices to children and adults whose hearing characteristics range from severe to profound. Even after nine years, not a day passes that I don’t marvel at the gift of sound and thank all those involved in providing this wondrous technology.

How the Cochlear Implant Works

Hearing aids amplify sound. For most people with hearing loss, hearing aids are an appropriate and effective remedy. But even the most sophisticated hearing aids may not offer sufficient benefit to people with severe to profound hearing loss. In contrast to a hearing aid, a cochlear implant does not make sounds louder. Rather, a cochlear implant bypasses the damaged hair cells and directly stimulates the remaining nerve fibers in the ear. The implant provides useful hearing and improved communication ability to the implant user and is a safe, reliable treatment for appropriate candidates with severe to profound hearing loss. Multi-channel implants have been in use for over 20 years.

A Cochlear Implant Works in the Following Way

1. Sounds are picked up by a microphone. In this case, the microphone is directional and located on a behind-the-ear headset.

2. Sound from the microphone is carried to the speech processor, which is a powerful miniaturized computer powered by batteries.

3. The speech processor filters, analyzes and digitalizes the sounded into coded signals.

4. The coded signals are sent from the speech processor to the transmitting coil.

5. The transmitter sends the coded signals across the skin to the internal implant receptor under the skin.

6. The cochlear implant delivers the electrical energy to an electrode array in the cochlea, which was inserted during surgery.

7. The electrodes stimulate the remaining nerve fibers, which then send the sound information through the auditory system to the brain for interpretation.

Donna Sorkin, MCP, was executive director of Self Help for Hard of Hearing People from 1993 to 1999 and served as executive director of the Alexander Graham Bell Association for the Deaf and Hard of Hearing from 1999 to 2001. She has been an enthusiastic cochlear implant user since 1992 and is now Vice President, Consumer Affairs at Cochlear Americas. In that capacity, she leads a range of activities at Cochlear aimed at the broad life needs of the cochlear implant community including appropriate educational options for children, early intervention, accessibility for people with hearing loss, and insurance reimbursement. She can be reached at dsorkin@cochlear.com