This study examines optimal conversions of speech sounds to audible electric currents in cochlear-implant listeners. The speech dynamic range was measured for 20 consonants and 12 vowels spoken by five female and five male talkers. Even when the maximal root-mean-square (rms) level was normalized for all phoneme tokens, both broadband and narrow-band acoustic analyses showed an approximately 50-dB distribution of speech envelope levels. Phoneme recognition was also obtained in ten CLARION implant users as a function of the input dynamic range from 10 to 80 dB in 10-dB steps. Acoustic amplitudes within a specified input dynamic range were logarithmically mapped into the 10-20-dB range of electric stimulation typically found in cochlear-implant users. Consistent with acoustic data, the perceptual data showed that a 50-60-dB input dynamic range produced optimal speech recognition in these implant users. The present results indicate that speech dynamic range is much greater than the commonly assumed 30-dB range. A new amplitude mapping strategy, based on envelope distribution differences between consonants and vowels, is proposed to optimize acoustic-to-electric mapping of speech sounds. This new strategy will use a logarithmic map for low-frequency channels and a more compressive map for high-frequency channels, and may improve overall speech recognition for cochlear-implant users.

10-■-Receptive-O-Expressive Pre 6 mo Evaluation Interval 12 mo Mean age equivalent language scores on Reynell Developmental Language Scales-Revised for 18 prelingually deafened children at preoperative interval with hearing aids (Pre) and 6 and 12 months after implantation with Clarion cochlear implant.

We analyzed published reports of the effect of age at implantation and the cause of and age at onset of deafness on speech perception benefit in children with cochlear implants, and compared these results with those of unreported trials of multichannel cochlear implants. Combining data from published and unpublished patient series was constrained by differences in test protocols between studies, but was made feasible by employing a meta-analysis in which data were converted into an ordinal classification scale that represented levels of communicative benefit. Results showed that more rapid gains in speech perception are associated with earlier age at implantation, and that speech perception results are independent of cause of or age at onset of deafness after 1 year of implant use. Moreover, with minor exceptions, there was no statistical difference between published and unpublished data, thereby indicating no publication bias in the literature. A meta-analytic approach is useful because it can clarify the quality of reported data and the direction of future research and, hopefully, foster collaboration in conducting and reporting future research. A standardized approach to reporting results in children is advised in order to produce a balanced interpretation of implant benefit and to facilitate wider understanding and dissemination of study conclusions. KEY WORDS-children, cochlear implant, speech perception.

ObjectiveTo demonstrate the performance benefit of the Automatic Scene Classifier (SCAN) algorithm available in the Nucleus® 6 (CP900 series) sound processor over the default processing algorithms of the previous generation Nucleus 5 (CP810) and Freedom® Hybrid™ sound processors.MethodsEighty-two cochlear implant recipients (40 Nucleus 5 processor users and 42 Freedom Hybrid processor users) listened to and repeated AzBio sentences in noise with their current processor and with the Nucleus 6 processor.ResultsThe SCAN algorithm when enabled yielded statistically significant non-inferior and superior performance when compared to the Nucleus 5 and Freedom Hybrid sound processors programmed with ASC + ADRO®.ConclusionThe results of these studies demonstrate the superior performance and clinical utility of the SCAN algorithm in the Nucleus 6 processor over the Nucleus 5 and Freedom Hybrid processors.