Success Factors for a Cochlear Implant
There are many factors that determine how well a person will perform with a cochlear implant. Arguably, the most important factors to the least important are as follows:
Outside factors -- Duration of deafness, age at implantation, residual hearing, and etiology--basically, things that are beyond our control. There is a huge variance in how well people do with implants, largely due to the wide degree of differences such factors among individuals.
Attitude and determination -- the amount of work and practice that you put into making it work is very important to making the most of the implant. It does take work! If possible, cochlear implant recipients should seek out auditory therapy to make the most of their implants. The implant is not a miracle cure for deafness, and many people find it frustrating and discouraging to undergo the long and difficult process of learning to hear with the implant.
Skill of audiologist and surgeon -- a good surgeon and audiologist can help ensure that recipients get the most that the implant has to offer them. You may want to ask your audiologist and surgeon how much experience they have with implants, and get a sense for how dedicated they may be to helping you in the years to come with any challenges that arise.
Type of device -- Newer generations of cochlear implants have improved the chances that people will hear well with them. This may not be as important as some of the other factors mentioned above, but when it comes to hearing, every bit counts. For an evaluation of the performance and speech comprehension differences between implants.
Below, is a more detailed description and explanation of some of the key success factors, most of which were derived from an National Institutes of Health (NIH) consensus paper:
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Etiology |
Meningitic deafness does not necessarily limit the benefit of cochlear implantation in the absence of central nervous system complications, cochlear ossification, or cochlear occlusion. Children with congenital deafness and children with prelingually acquired meningitic deafness, for example, achieve similar auditory performance if the cochlear implant is received before age 6 years. In general, etiology does not appear to impact auditory performance in either children or adults. |
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Age at Onset of Deafness |
The age of onset continues to have important implications for cochlear implantation, depending on whether the hearing impairment occurred before (prelingual), during (perilingual), or after (postlingual) learning speech and language. Children or adults with postlingual onset of deafness had better auditory performance than children or adults with prelingual or perilingual onsets. However, the difference between children with postlingual and prelingual-perilingual onsets appears to lessen with time. Large individual differences remain within each group. |
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Age at Implantation |
Prelingually or perilingually deafened persons who were implanted in adolescence or adulthood generally do not achieve as good auditory performance as those implanted during childhood, although individual differences exist. However, it is still unclear whether implantation at age 2, for example, ultimately results in better auditory performance than implantation at age 3 |
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Residual Hearing |
Cochlear implants tend to give people with profound deafness a level of auditory performance that is similar to, or better than, the performance of people with severe hearing impairment who use hearing aids. No residual hearing is typically defined as profound hearing loss and no open-set speech recognition. However, the degree of preimplantation residual hearing does not predict postimplantation auditory performance. |
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Electrophysiological Factors |
Some surviving spiral ganglion cells are necessary for auditory performance with a cochlear implant. Degenerative changes occur in both ganglion cells and central auditory neurons following sensorineural deafening. Although a relationship between the number of surviving ganglion cells and psychophysical performance has been demonstrated in animals, a direct relationship between ganglion cell survival and level of auditory performance in humans has not been shown. |
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Attitude and Determination |
People who have “high hopes and low expectations” tend to adapt better to the psychological consequences of receiving an implant. A positive attitude can make the difference between two equal recipients and the inner strength it takes them to learn to use the implant and communicate orally. Auditory therapy (on your own or professionally) and a willingness to learn to listen with the implant are very, very important to doing well with it. |
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Skill of audiologist and surgeon |
There are some minor risks to cochlear implant surgery, so the amount of experience and skill of the surgeon may be important to consider. Perhaps more important, though, is the skill and experience of the audiologist. The audiologist helps customize the implant to the recipient, and tweaks its settings to enable the recipient to hear at his or her best with the implant. A good audiologist can make a lot of difference in customizing an implant that provides its user with the most benefit. It is often worth traveling a little further if it means getting to a clinic with a surgeon and audiologist that you are comfortable with. |
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Type of Device (Implant Engineering and Software Differences) |
There are three manufacturers of cochlear implants—Advanced Bionics, Cochlear Corp, and Med-El. Each one uses a different engineering platform and runs different speech coding software. For an explanation of the different types of implants, and the advantages and disadvantages of each, click here. |