Channel discrimination along all contacts of the cochlear implant electrode array and its relation to speech perception

AbstractObjective: To test the channel discrimination of cochlear implant (CI) users along all contacts of the electrode array and assess whether this is related to speech perception.Design: CI recipients were tested with a custom-made channel discrimination test. They were asked to distinguish a target stimulus from two reference stimuli in a three-alternative forced choice (3AFC) task. The target stimulus was evoked using current steering, with current steering coefficients (α) of 1, 0.5 and 0.25. The test provided a discrimination score (Dα) for each electrode contact along the array.Study sample: Thirty adults implanted with a CI from Advanced Bionics.Results: Large variations in Dα scores were observed, both across the electrode array and between subjects. Statistical analysis revealed a significant channel-to-channel variability in Dα score (p < 0.01). Further, there was a significant relationship between subjects’ Dα scores and their speech perception in quiet (p < 0.001).Conclusions: The large var...