Tone perception development in Mandarin-speaking children with cochlear implants

Objective: The purpose of this study was to examine the longer-term effects of cochlear implant (CI) use on tone perception by evaluating improvement in Mandarin tone recognition in children with CIs 2 and 3 years post CI activation, and to explore the effects of implant age, chronological age and duration of CI use on the development of tone perception.Methods: Tone perception was assessed in 29 bilateral profound hearing impaired children (mean chronological age = 4.6 years, SD = 0.7 years) with unilateral CIs at 24 and 36 months after CI activation using the tone perception subtest in the Mandarin Early Speech Perception (MESP-T) test.Results: Children's tone recognition for tone pairs and individual tones improved significantly between 2 and 3 years post CI use, showing an increase in average tone recognition score from 73.2% to 81.8%, which was significantly higher than chance level (i.e. 50%). There was no significant correlation between tone recognition ability and either implant age or chronological age at two evaluation points. Further analysis revealed that the tone recognition score for tone pair 2-3 was significantly lower than that for other tone pairs except for tone pair 2-4.Conclusions: Longer CI experience can significantly improve tone recognition ability in CI children between 2 and 3 years post CI activation.