AO Journal Group: 8 Channel to 16 Channel Cochlear Implant Conversion.

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This article review was submitted by Michelle L. Hughes, Ph.D., CCC-A, Boys Town National Research Hospital Audiology Online Contributing Editor, Cochlear Implants

Article:

Dunn, C. C, Tyler, R. S., Witt, S. A., & Gantz, B. J. (2006). Effects of converting bilateral cochlear implant subjects to a strategy with increased rate and number of channels. Annals of Otology, Rhinology, & Laryngology, 115 (6), 425-432.

Article Summary:

This study examined the effect of converting bilateral cochlear implant (CI) recipients from an 8-channel CIS strategy to a 16-channel HiResolution (HiRes) strategy. The purposes of the study were to: (1) determine whether improvements in speech perception ability could be achieved with a faster-rate processing strategy that utilizes more channels (HiRes), (2) compare performance with HiRes-P versus HiRes-S, and (3) evaluate speech perception performance after alternating between the two HiRes strategies for one month.

Seven adult subjects participated. All subjects received bilateral Advanced Bionics CII HiFocus implants, with each subject receiving both implants in a single surgery. All subjects used CIS for at least 18 months prior to the study. An ABAB design was used to evaluate the effectiveness of switching from CIS to HiRes-P and HiRes-S. Sentences in noise were used to evaluate speech perception ability. The results showed immediate improvement (no acclimatization time) with HiRes for five subjects and significant improvement for six of the seven subjects after just 1 month of HiRes use. In the comparison between HiRes-P and HiRes-S, this study found significantly better performance with HiRes-P for two subjects and no significant difference for the remaining five subjects. Results from this study suggest much greater improvement with HiRes for bilateral recipients compared to previously published conversion results for unilateral recipients.