Spectral vs Temporal pitch in CI users listening to real-life stimuli

Background<br/>Pitch perception is known to be significantly impaired in cochlear implant (CI) users. Previous research has indicated that pitch perception of CI users depends mainly on temporal cues, while normal hearing (NH) listeners rely heavily on spectral cues. However, recent studies with more realistic sound stimuli challenge this distinct separation of mechanisms between NH and CI users. They suggest that CI users may also utilize spectral cues alongside temporal cues. This study aims to clarify the relative contributions of spectral and temporal cues to pitch perception of CI users in realistic sound stimuli.<br/><br/>Methods<br/>Psychometric functions for F0 discrimination were collected in CI listeners, using triplets of consonant-vowel syllables in a three-alternative forced choice task. Two modalities of stimulation were used: acoustic and electric, through a research interface. For the latter, electrodograms were recorded in advance with the participants' own program settings, as if the participant was seated in the experiment room. Then, the electrodograms were processed to create four conditions: unaltered, suppressed temporal, suppressed spectral, and both cues suppressed. Temporal cues were suppressed by filtering the envelope of each channel with a comb-filter at the F0 and harmonics. Spectral cues were suppressed by raising or lowering the current levels of the odd-one-out triplet to the current levels of the reference, using short time windows.<br/><br/>Results<br/>It is expected that pitch cue suppression will increase the difficulty of the task, i.e. shifting the psychometric function towards larger F0 differences. By analyzing the change in performance when temporal and/or spectral cues are suppressed, we hope to reveal the relative contributions of both cues to pitch perception of realistic speech stimuli. The acoustic and unaltered stimulation conditions will be compared to assess whether they produce the same percepts. Data will be available at the time of the meeting