by Gail A. Linn
When the U.S. Food and Drug Administration first approved cochlear implants for adults in 1985, the technology was recommended for postlingually deafened adults with hearing losses greater than 100 dB and no discernable communication benefit from a hearing aid.
FDA approval has now been extended to include children 12 months of age and above and has expanded the audiologic criteria for adults to the 70–80 dB range and 90 dB for children. Candidacy will continue to change as the technology improves, but three main questions will always need to be answered:
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It is physically possible to implant the device, and does the patient’s medical condition make it advisable?
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Is the individual going to receive more communication benefit from the cochlear implant than a traditional hearing aid or from no hearing prosthetic at all?
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Is the patient’s psychological, familial, educational, and rehabilitative status such that the implant can be kept working throughout the individual’s life?
Success Factors
It is difficult to accurately predict performance with a cochlear implant, but indicators for success have been reported:
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Postlingually deafened adults with a shorter duration of deafness tend to achieve the highest speech perception scores.
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Adults with prelingual, long-term deafness who receive a cochlear implant typically do not develop open-set word recognition abilities, although they do recognize environmental sounds and may develop enhanced speachreading abilities.
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Children generally demonstrate significant improvement in closed-set word recognition but obtain limited open-set word recognition abilities. Unlike adults, children’s speech perception abilities improve with maturation and increased experience with the device.
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Congenitally or prelingually deafened children appear to experience the greatest benefit when implanted prior to age 2.
Gail A. Linn is ASHA’s director of audiology practice in industry and private practice
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