Restoring speech perception with cochlear implants by spanning defective electrode contacts

Abstract

Conclusion: Even with six defective contacts, spanning can largely restore speech perception with the HiRes120 speech processing strategy to the level supported by an intact electrode array. Moreover, the sound quality is not degraded. Objectives: Previous studies have demonstrated reduced speech perception scores (SPS) with defective contacts in HiRes120. This study investigated whether replacing defective contacts by spanning, i.e. current steering on non-adjacent contacts, is able to restore speech recognition to the level supported by an intact electrode array. Methods: Ten adult cochlear implant recipients (HiRes90K, HiFocus1J) with experience with HiRes120 participated in this study. Three different defective electrode arrays were simulated (six separate defective contacts, three pairs or two triplets). The participants received three take-home strategies and were asked to evaluate the sound quality in five predefined listening conditions. After 3 weeks, SPS were evaluated with monosyllabic words in quiet and in speech-shaped background noise. Results: The participants rated the sound quality equal for all take-home strategies. SPS with background noise were equal for all conditions tested. However, SPS in quiet (85% phonemes correct on average with the full array) decreased significantly with increasing spanning distance, with a 3% decrease for each spanned contact.