Bimodal benefit in categorical perception of lexical tones for Mandarin-speaking children with cochlear implants

Abstract

Bimodal hearing with the combined use of a cochlear implant (CI) and a contralateral hearing aid (HA) has been demonstrated beneficial for deaf individuals in many aspects of speech perception. However, it remains inconsistent whether CI users can obtain bimodal benefit in lexical tone perception. To disentangle this question, Mandarin-speaking children using a CI and an HA in opposite ears were recruited to conduct perceptual tasks with a tonal continuum varying from Tone 1 to Tone 2. All participants were assessed with CI only and CI + HA conditions. Results showed typical S-shaped functions for the identification curves in both device conditions. Moreover, a sharper identification boundary and a higher peakedness score have been exhibited for the CI + HA relative to the CI only condition. The findings suggested that CI children on the whole show categorical perception for Mandarin tones and bimodal hearing could enhance their tonal categorization ability.