The Graduate Center, City University of New York, Speech-Language-Hearing Sciences, 365 Fifth Avenue, New York, NY 10016, USA.
J Speech Lang Hear Res. 2010 Jun;53(3):757-77. doi: 10.1044/1092-4388(2009/08-0123).
The authors investigated the neurophysiological bases of vowel perception in children with specific language impairment (SLI) compared with typical language development (TLD) controls using 250-ms phonetically similar vowels. In a previous study, children with SLI showed a poor neurophysiological response (the mismatch negativity [MMN]) to 50-ms versions of these vowels, regardless of whether attention was directed to (attend) or away (passive) from the auditory modality (V. Shafer, M. Morr, H. Datta, D. Kurtzberg, & R. Schwartz, 2005). They hypothesized that longer vowels would allow for improved speech perception.
Brain responses were elicited to the vowel contrast in 2 conditions: (a) attend and (b) passive. Behavioral discrimination and identification responses were also examined.
Both SLI and TLD groups showed evidence of discrimination (MMN) of the vowels in the attend and passive conditions. Only subtle differences in the scalp topography of a late negative (LN) brain component were observed between groups. The SLI compared with the TLD group showed significantly poorer identification of these long vowels, as found previously with the shorter vowels.
Increased vowel duration can improve discrimination in children with SLI. However, poor identification of these longer vowels by some children with SLI suggests a deficit in long-term phonological representations or accessing these representations.
作者使用 250 毫秒的语音相似元音，比较了特定语言障碍（SLI）儿童与典型语言发展（TLD）对照组的元音感知的神经生理基础。在之前的一项研究中，无论注意力是指向（attend）还是远离（passive）听觉模式（V. Shafer、M. Morr、H. Datta、D. Kurtzberg 和 R. Schwartz，2005），SLI 儿童对这些元音的 50 毫秒版本的神经生理反应（失匹配负波 [MMN]）较差。他们假设较长的元音将允许改善语音感知。
在两种条件下（a）注意和（b）被动，对元音对比产生脑反应。还检查了行为辨别和识别反应。
SLI 和 TLD 组在注意和被动条件下均显示出对元音的辨别（MMN）的证据。仅观察到组间晚期负（LN）脑成分的头皮拓扑结构存在细微差异。与 TLD 组相比，一些 SLI 儿童对这些长元音的识别明显较差，这与以前对较短元音的研究结果一致。
增加元音持续时间可以提高 SLI 儿童的辨别能力。然而，一些 SLI 儿童对这些较长元音的识别能力较差，表明他们在长期语音表征或访问这些表征方面存在缺陷。
