Dual-Electrode Interaural Time Difference Sensitivity in Electric Hearing: Between-Electrode Delay and Peripheral Interference (vor Ort)

* Presenting author
Day / Time: 23.03.2022, 14:40-15:00
Room: 9-01.
Typ: Regulärer Vortrag
Session: Psychoakustik 4
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Perception of interaural time differences (ITDs) is impaired in cochlear-implant (CI) listeners compared to normal-hearing listeners. For single-electrode stimulation, several explanatory factors have been proposed. For multi-electrode stimulation, peripheral interference (or channel interaction) is another potentially limiting factor. Here, ITD sensitivity was measured in five bilateral CI listeners using dual-electrode stimuli. Stimuli consisted of an interaurally ITD-matched target electrode (T) paired with a flanker electrode (F). T was located in the center of the array, a narrowly and a widely spaced F on either side of T. Narrow Fs were adjacent to T (maximum interference) and wide Fs were selected based on forward-masked spatial tuning curves. Per electrode, stimuli were either low-rate unmodulated 100-pps pulse trains, high-rate 1000-pps pulse trains with a 100-Hz amplitude modulation (AM), or high-rate AM stimuli with additional short inter-pulse interval pulses. The delay between T and F was varied within the pulse respectively AM period. For low-rate stimuli, results indicate a systematic delay effect, with best performance for short delays and wide T-F separation, suggesting an important role of peripheral interference. The performance for high-rate stimuli was largely at chance level. The data will be compared to rate-pitch data collected with a matched setup.