Speaker
Description
To date, the role of spectral and temporal cues in pitch perception with cochlear implants (CIs) remains debated. Previous research has indicated that pitch perception of CI users depends mainly on temporal cues. However, these studies used either well-controlled but artificial stimuli or indirect measures to assess cues. Using a novel approach, we have directly quantified the relative contributions of spectral and temporal cues to voice pitch perception by controlling their availability in the electrical stimulation pattern.Psychometric functions for fundamental frequency discrimination were collected using triplets of consonant-vowel syllables in a 3AFC odd-one-out task. The population featured 32 CI listeners varying in age and age-at-implantation, all using n-of-m strategies. Stimuli were presented acoustically or via direct stimulation. For the latter, pulse patterns were recorded in advance using the same processor type and the exact settings of each participant. The recorded patterns were then modified to suppress temporal or spectral cues. Temporal cues were suppressed by filtering out F0-related amplitude modulations from the channel envelopes. Spectral cues were suppressed by amplifying or attenuating current levels to produce similar current distributions for the three intervals in each trial. In these direct stimulation conditions, the altered pulse patterns were streamed to the participant using a research interface.Our results show that CI users relied heavily on temporal cues when available. In speech with less temporal cues, CI users had greater difficulty but some did fall back on spectral cues. While the general scores were higher for the younger participants compared to older participants, their relative cue weightings appeared similar.