Parameter-specific Morphing Reveals Contributions of Timbre and F0 Cues to the Perception of Voice Gender and Age in Cochlear Implant Users

Please note: A peer-reviewed version of the paper is currently in press in the Journal of Speech, Language, and Hearing Research. Peer-reviewed publication DOI will be provided when available. Purpose: Using naturalistic synthesized speech, we determined the relative importance of acoustic cues in voice gender and, for the first time, vocal age perception in Cochlear Implant (CI) users. Method: We investigated 28 CI users’ abilities to utilize fundamental frequency (F0) and timbre in perceiving voice gender (Experiment 1) and additional timing cues in perceiving vocal age (Experiment 2). TANDEM-STRAIGHT-based parameter-specific voice morphing was used to control acoustics in voice stimuli. Individual differences in CI users’ performance were captured by quantifying deviations from a control group of 19 normal hearing (NH) listeners. Results: CI users’ gender perception seemed exclusively based on F0, whereas the NH listeners efficiently used timbre. For age perception, timbre was more informative than F0 for both groups, with minor contributions of temporal cues. While a few CI users performed comparable to NH listeners overall, others were at chance. Separate analyses confirmed that even in high performing CI users, gender perception was almost exclusively based on F0. While high performers could discriminate age in male and female voices, low performers were close to chance overall, but used F0 as misleading cue to age (classifying female voices as young and male voices as old). Satisfaction with CI generally correlated with performance. Conclusions: We confirmed that CI user gender classification bases mainly on F0, but high performers could make reasonable usage of TIMBRE cues in both gender and age perception. Overall, parameter-specific morphing is a promising approach to objectively assess individual profiles of CI users abilities to perceive nonverbal social-communicative vocal signals.