人工耳蜗植入儿童在噪声环境与耳语条件下的汉语声调感知

Mandarin Tone Recognition in the Children with Cochlear Implants under Noisy and Whispered Conditions

人工耳蜗(Cochlear Implants,CI)作为成功应用于听力康复和重建的神经假体,目前已基本满足人工耳蜗植入儿童(CI儿童)在安静环境下的听力需求,但是由于CI对基频信息缺乏有效编码,因此CI儿童的声调识别仍然存在缺陷,尤其是在噪声环境下识别效果尚不明晰。此外,耳语作为一种不含基频信息的特殊发声态,可为CI儿童的声调感知研究提供特别的视角。为此,本文设计了两个听觉感知实验,以年龄与性别匹配的健听(NH)儿童为对照组,考察CI儿童在噪声环境和耳语条件下的汉语声调识别。实验一发现,CI儿童的声调识别率总体上低于NH儿童,而且抗噪能力弱于NH儿童,尤其在–5dB SNR条件下与NH儿童差距明显;两组儿童均表现出T4、T1较T2、T3更易识别,特别是CI儿童对T4的识别率与NH儿童没有显著差异。实验二发现,CI和NH儿童在耳语条件下的声调识别率均显著低于正常语音条件,但是NH儿童受到的影响更大,仅区分T2-T4比CI儿童有优势。研究揭示了CI儿童在噪声环境与耳语条件下对汉语声调的感知规律,验证了声调感知的主要与次要线索,并有助于优化声调语言的听力康复方案。

Cochlear implants(CIs),as a successful neuroprosthesis for hearing rehabilitation,have basically met the hearing needs of the children with CIs(CI children)in quiet environments.However,due to the lack of effective coding of fundamental frequency in CIs,CI children still had difficulty in tone recognition,especially in noisy environments.In addition,as a special phonation type in which fundamental frequency is missing,whispered speech provides a special perspective for studying tone recognition in CI children.Hence,this study conducted two auditory perception experiments to investigate CI children’s recognition of Mandarin tones in noisy and whispered speech,taking the age and gender matched normal hearing(NH)children as the control group.In Experiment 1,the rate of tone recognition in the CI group was generally lower than that in the NH group,and the CI group was more affected by noisy environments than the NH group,especially in the condition of–5 dB SNR;Also,both groups had a better recognition for T4/T1 than for T2/T3.In Experiment 2,both groups showed a significantly lower rate of tone recognition for whispered speech than for normal speech,but the NH group degraded even more,with only an advantage over the CI group in discriminating T2 and T4 under the whispered condition.In sum,this study revealed tone recognition characteristics of CI children in noisy and whispered speech,verified the primary and secondary cues of Mandarin tone perception,and helped further improve the scheme of hearing rehabilitation for tone language speakers.