Cochlear Implant Candidacy Revisited
Lovett, Vickers, and Summerfield (2015) report their observational study of children with bilateral cochlear implants (CIs) compared to children with bilateral hearing aids (HAs) to better determine a criterion for CI candidacy for young children. Determining CI candidacy criteria is difficult, as candidacy is assessed based on (often estimated) pure-tones, while outcomes are measured through listening and language skills. The authors note that CI outcomes cannot be predicted for a specific individual, as the variation in outcomes-based performance is huge (see Davidson, 2011).
The authors explore, examine, and offer insight into resolving the disconnect between these two factors. Seventy-one children (mean age 64 months) from the United Kingdom participated. Twenty-eight children had bilateral CIs implanted simultaneously; 43 children wore bilateral hearing aids. The ability to understand speech in quiet, pink noise, and in the presence of two-talker babble was assessed with the end goal being to determine the unaided, four frequency pure-tone average (4FPTA based on 500, 1000, 2000 and 4000 Hz) at which children had a 4:1 chance of a better outcome (see Boothroyd, 1993) with CIs, rather than HAs. For some children, the 4FPTA could not be determined. For those children, the authors provided two (2FPTA, 2000 and 4000 Hz) and three frequency (3FPTA, 500, 1000 and 2000 Hz) PTA guidelines.
Lovett, Vickers, and Summerfield report that to achieve a likelihood of a 4 fold advantage through CIs, with respect to the metrics used in their study, a mean 4FPTA of 80 dB HL, and given a 2FPTA, the mean was 85 dB HL. Currently, in the United States (2015), the FDA approves CIs for children ages 12 to 23 months, if their 3FPTA is 90 dB or greater.
For More Information, References, and Recommendations
Boothroyd A. (1993) Profound Deafness. In R. Tyler (Ed). Cochlear Implants—Audiological Foundations (pages 1-33). London: Whurr.
Davidson LS, Geers AE, Blamey PJ. (2011) Factors contributing to Speech Perception Scores in Long-Term Cochlear Implant Users. Ear & Hearing 32(Suppl 1):19S-26S.
Lovett RES, Vickers AD, Summerfield AQ (2015) Bilateral Cochlear Implantation for Hearing Impaired Children—Criterion od Candidacy Derived from an Observational Study. Ear & Hearing 36(1):14-23