Developmental effects on voice and speech-on-speech in single-sided or bilaterally deaf children with cochlear implants

Postlingually deaf adult cochlear implant (CI) users have difficulties perceiving voice cues and using them for better perception of speech in speech maskers. Here, we explore how neuroplasticity related development may affect voice and speech-on-speech perception with CIs. In a group of early-implanted school-age children with bilateral CIs, and a group of children with prelingual single-sided deafness with a CI (SSD + CI), we measured sensitivity to voice fundamental frequency (F0) and vocal-tract length (VTL; Experiment 1), voice gender categorization (Experiment 2), and the benefit from voice cue differences in speech-on-speech perception (Experiment 3). In some tasks, children with CIs had higher scores than adults with CIs, however, the patterns differed between the two groups of children. Despite a normal-hearing ear, SSD + CI children do not seem to solely rely on this ear for voice cue perception. The voice gender categorization and speech-on-speech perception scores of this group fall in between the scores of children with bilateral CIs and adults with a CI. These results suggest that voice cues are transmitted through the implant to a certain degree, and their perception seems to be affected by both developmental factors and the amount of experience with normal hearing or with an implant.