Speech Perception In Noise Of Mandarin-speaking Children With Cochlear Implants

Part 1 Speech recognition performance analysis of children with cochlear implants in steady-state noise and competing speechObjective:Due to the lack of fine-coded fundamental frequency(FO)cues in cochlear implant(Cl)devices,the speech perception of mandarin-speaking Cl users in steady-state noise(SSN)and competing speech was not ideal.This study explores the speech recognition performance of Cl and normal hearing(NH)listeners in SSN and competing speech.Methods:Sixteen Mandarin-speaking Chinese Cl users,twelve NH children and ten NH adults participated in the study.Speech recognition threshold(SRTs)of these subjects in steady noise and competing speech were measured.Results:For all maskers,SRTs in NH children were significantly lower than Cl children.In NH children,the age at testing was significantly associated with SRTs in competing speech,but not in Cl children.Cl children were unable to benefit from voice gender differences between the target and masker speech.Mrhen the target and masker speech gender was different,the duration of deafness in Cl children was significantly correlated with SRTs in competing speech.Conclusion:Cl children are more susceptible to information masking and cannot separate competing speakers by FO differences.The age at testing in NH children and the duration of deafness in Cl children were significantly correlated with SRTs in competing speech,indicating that auditory deprivation may limit developmental processes important for talker segregation.Thus,early cochlear implant can help to separate competing speakers.Part2 Release from informational masking in Mandarin-speaking cochlear implant childrenObjective:Due to poor spectral resolution,Cl users are more susceptible to information masking(IM).This study examined the effects of various aspects of IM(intelligibility,native language effects,talker gender,and the number of talkers)on speech recognition by NH and Cl children,and analyzed their release from IM in different masking conditions.Methods:Fifteen Mandarin-speaking Chinese Cl children and twelve NH children participated in the study.SRTs in different masking conditions were measured in the presence of time-forward or time-reversed native or non-native eompeting speech.Results:For all maskers,SRTs was significantly lower for NH children than for Cl children.For NH and Cl children,SRTs was lower in the presence of a non-native-language masker than a native masker.NH children were able to benefit from voice gender differences between the target and masker,but Cl children were not.Release from IM was larger for NH than for Cl children,and largest with the non-native masker.Conclusion:Better performance with non-native and time-reversed maskers for both NH and Cl listeners.NH listeners experienced greater release from IM than did Cl listeners.Part3 Release from information masking of binaural redundancy effect in children with normal hearing in competitive speechObjectives When speech and noise are presented directly in front of a listener,binaural listening offers an advantage over monaural listening,which is called binaural redundancy effect.The binaural redundancy effect is usually evaluated in quiet or SSN,and it is unclear whether the effect exists in competing speech.This study evaluated the binaural redundancy effect in competing speech to explore the release from IM in NH listeners.Methods:Twelve NH children and ten NH adults participated in the study.Monaural and binaural SRTs were measured for competing speech in NH listeners.The target-masker voice gender was the same or different.Results:For all maskers,SRTs was significantly lower for NH adults than for NH children.Both NH children and children were able to benefit from voice gender differences between the target and masker.In competing speech,SRTs of NH listeners did not benefit significantly from binaural redundancy.Instead,when the voice gender was the same,NH children had significant binaural interference,while NH adults had less binaural interference.Conclusion:Compared to monaural listening,binaural listening may offer little advantage or even interference in competing speech.Binaural listening was unable to significantly improve the ability of releasing from IM in NH listeners in competing speech.