Yang Jing, Xu Li
Department of Communication Sciences and Disorders, University of Wisconsin-Milwaukee.
Division of Communication Sciences and Disorders, Ohio University, Athens.
J Speech Lang Hear Res. 2021 Feb 17;64(2):664-682. doi: 10.1044/2020_JSLHR-20-00469. Epub 2021 Feb 1.
Purpose The purpose of this study was to characterize the acoustic profile and to evaluate the intelligibility of vowel productions in prelingually deafened, Mandarin-speaking children with cochlear implants (CIs). Method Twenty-five children with CIs and 20 age-matched children with normal hearing (NH) were recorded producing a list of Mandarin disyllabic and trisyllabic words containing 20 Mandarin vowels [a, i, u, y, ɤ, ɿ, ʅ, ai, ei, ia, ie, ye, ua, uo, au, ou, iau, iou, uai, uei] located in the first consonant-vowel syllable. The children with CIs were all prelingually deafened and received unilateral implantation before 7 years of age with an average length of CI use of 4.54 years. In the acoustic analysis, the first two formants (F1 and F2) were extracted at seven equidistant time locations for the tested vowels. The durational and spectral features were compared between the CI and NH groups. In the vowel intelligibility task, the extracted vowel portions in both NH and CI children were presented to six Mandarin-speaking, NH adult listeners for identification. Results The acoustic analysis revealed that the children with CIs deviated from the NH controls in the acoustic features for both single vowels and compound vowels. The acoustic deviations were reflected in longer duration, more scattered vowel categories, smaller vowel space area, and distinct formant trajectories in the children with CIs in comparison to NH controls. The vowel intelligibility results showed that the recognition accuracy of the vowels produced by the children with CIs was significantly lower than that of the NH children. The confusion pattern of vowel recognition in the children with CIs generally followed that in the NH children. Conclusion Our data suggested that the prelingually deafened children with CIs, with a relatively long duration of CI experience, still showed measurable acoustic deviations and lower intelligibility in vowel productions in comparison to the NH children.
目的 本研究旨在描述语前聋、说普通话的人工耳蜗植入（CI）儿童的声学特征，并评估其元音发音的可懂度。方法 记录25名接受人工耳蜗植入的儿童和20名年龄匹配的听力正常（NH）儿童说出的包含20个普通话元音[a、i、u、y、ɤ、ɿ、ʅ、ai、ei、ia、ie、ye、ua、uo、au、ou、iau、iou、uai、uei]的普通话双音节和三音节单词列表，这些元音位于第一个辅音-元音音节中。接受人工耳蜗植入的儿童均为语前聋，7岁前接受单侧植入，人工耳蜗使用平均时长为4.54年。在声学分析中，在测试元音的七个等距时间点提取前两个共振峰（F1和F2）。比较人工耳蜗植入组和听力正常组的时长和频谱特征。在元音可懂度任务中，将听力正常儿童和人工耳蜗植入儿童提取的元音部分呈现给六名说普通话的听力正常的成年听众进行识别。结果 声学分析表明，人工耳蜗植入儿童在单元音和复合元音的声学特征上与听力正常对照组存在差异。与听力正常对照组相比，人工耳蜗植入儿童的声学差异表现为时长更长、元音类别更分散、元音空间面积更小以及共振峰轨迹不同。元音可懂度结果显示，人工耳蜗植入儿童发出的元音识别准确率显著低于听力正常儿童。人工耳蜗植入儿童的元音识别混淆模式总体上与听力正常儿童一致。结论 我们的数据表明，与听力正常儿童相比，有较长人工耳蜗使用经验的语前聋人工耳蜗植入儿童在元音发音方面仍表现出可测量的声学差异和较低的可懂度。
