QWeight CI: Binaural Cue Reweighting in Cochlear-Implant Listeners

Subproject of QWeight

Duration: June 2019 - Nov 2021

Funding:

• uni:docs Fellowship Program for Doctoral Candidates of the University of Vienna
• OeAD, project SpaCI (#MULT_DR 11/2017)

Objective:

Normal-hearing (NH) listeners rely on two binaural cues, the interaural time (ITD) and level difference (ILD), for azimuthal sound localization. Cochlear-implant (CI) listeners, however, rely almost entirely on ILDs. One reason is that present-day clinical CI stimulation strategies do not convey salient ITD cues. But even when presenting ITDs under optimal conditions using a research interface, ITD sensitivity is lower in CI compared to NH listeners. Since it has recently been shown that NH listeners change their ITD/ILD weighting when only one of the cues is consistent with visual information, such reweighting might add to CI listeners' low perceptual contribution of ITDs, given their daily exposure to reliable ILDs but unreliable ITDs. This hypothesis was studied in a multi-day lateralization training visually reinforcing ITDs, flanked by a pre- and post-measurement of ITD/ILD weights without visual reinforcement.