New cochlear implant research coding strategy based on the MP3000™ strategy to reintroduce the virtual channel effect

Abstract Conclusion: Results for speech recognition in noise tests when using a new research coding strategy designed to introduce the virtual channel effect provided no advantage over MP3000™. Although statistically significant smaller just noticeable differences (JNDs) were obtained, the findings for pitch ranking proved to have little clinical impact. Objectives: The aim of this study was to explore whether modifications to MP3000 by including sequential virtual channel stimulation would lead to further improvements in hearing, particularly for speech recognition in background noise and in competing-talker conditions, and to compare results for pitch perception and melody recognition, as well as informally collect subjective impressions on strategy preference. Methods: Nine experienced cochlear implant subjects were recruited for the prospective study. Two variants of the experimental strategy were compared to MP3000. The study design was a single-blinded ABCCBA cross-over trial paradigm with 3 weeks of take-home experience for each user condition. Results: Comparing results of pitch-ranking, a significantly reduced JND was identified. No significant effect of coding strategy on speech understanding in noise or competing-talker materials was found. Melody recognition skills were the same under all user conditions.