Electrodographic analysis and field evaluation of the Speak coding strategy.
The Speak speech-coding strategy for the Nucleus Minisystem-22 cochlear implant continuously analyzes the speech signal using 20 digitally programmable band-pass filters and presents up to 10 spectral maxima to the implanted electrodes. To analyze the performance of this system for a variety of speech sounds in quiet and noise, the stimulation patterns of the implanted electrode array were reconstructed from the transmitted radio frequency signals by software as electrodograms and compared to electrodograms generated by other speech-coding strategies, as well as to the spectrograms of the input signals. The performance with the Speak strategy relative to that with the Multipeak (Mpeak) speech-processing strategy was also evaluated in a field trial study with 20 native German-speaking cochlear implant users from four European implant centers, involving a variety of auditory perceptual tasks in an ABAB paradigm over a 12-week period. Vowel, consonant, and monosyllable word tests, as well as sentence tests in quiet and noise, were conducted. Significant differences in group mean scores for most speech recognition subtests were obtained for the Speak versus the Mpeak strategy, with the largest overall improvements observed for the sentence tests in noisy conditions.
Dillier
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ENT Department, University Hospital Zürich, Switzerland.
Bögli
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H
Lai
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WK
D000328:Adult; D003054:Cochlear Implants; D003638:Deafness / Q000534:rehabilitation; D006801:Humans; D010700:Phonetics; D013018:Sound Spectrography; D013067:Speech Perception