Binaural Processing in a New Cochlear-Implant Paradigm Inserting Extra Pulses with Short Inter-Pulse Intervals
* Presenting author
Cochlear-implant (CI) listeners face degraded selective hearing because they lack sensitivity to both interaural-time-difference (ITD) and pitch cues. One major reason is the replacement of the acoustic temporal fine structure by periodic high-rate pulse trains to avoid electric-field interactions. A second major reason is a perceptual limitation of CI listeners in the maximum pulse rate up to which ITD and pitch cues are salient. Recently, a new approach relying on inserting extra pulses with short inter-pulse intervals (SIPIs) into the high-rate carrier pulse trains has been shown to enhance ITD and pitch sensitivity while likely maintaining speech understanding. In this contribution, a concept for a new binaural CI stimulation paradigm which implements the SIPI approach is presented. In this paradigm, by applying binaural models of normal hearing, the ITD is extracted from a binaural audio signal. That ITD, combined with the envelope-modulation information, defines the positioning of the SIPI pulses. This concept allows to enhance ITD cue precision through binaural processing by integrating reliable ITD information across frequencies or electrodes, respectively. In the contribution, various models and parameters will be discussed. Further, strategies how to avoid conflicts in the across-electrode timing of the SIPI pulses will be outlined.