The Neurodevelopmental Basis of Speech Discrimination

描述(由申请人提供)：许多研究报告了幼儿语言处理缺陷和语言障碍之间的联系(例如，Tallal等人，1991年)。然而，这些赤字之间的因果关系仍不清楚。要弄清这种关系的性质，第一步是确定婴幼儿的语音处理能力是否与后来的语言处理能力相关(Trehub&Henderson，1996)。因此，这个项目的主要目的是确定大脑在生命最初几年的言语辨别能力与后来的语言发展之间的关系。事件相关电位(ERPs)将被用来为3至12个月大的婴儿和蹒跚学步的婴儿区分语音相似的短元音对比(I与E和BLP与BEP)的神经过程提供一个指数。我们之所以选择这些元音对比，是因为语言技能较差的儿童在处理简短元音方面存在困难(初步研究1；Stark和Heinz，1996；Leonard等人，1992)。其中一组婴儿将来自西班牙语-英语双语家庭，因为研究表明，在发育过程中，接触不同分布的语音和音节结构会影响语音类别的发展。在一项纵向研究中，事件相关电位的测量，如峰潜伏期、波幅、成分的地形图等，将与6、12、18、24和36个月龄时获得的言语和语言能力的行为测量相关。在横断面设计中，我们将检验3个月至10岁儿童和成年人这些言语对比的脑辨别的事件相关电位表现和行为辨别的变化。这项横断面调查的目的是提供关于大脑和行为歧视之间的关系的信息，这是我们在纵向设计中无法获得的。本研究的具体目的是：1)确定出生后1年的言语知觉发展与后来的言语和语言发展措施之间的关系；2)确定大脑与3个月至10岁元音对比的行为辨别指数之间的关系；3)利用大脑和这些刺激加工的行为指数来确定输入(单语与双语)对言语辨别的影响。

DESCRIPTION (provided by applicant): Numerous studies have reported an association between speech processing deficits and language impairments in young children (e.g. Tallal, et al., 1991). However, the causal relationship between these deficits remains unclear. A first step towards clarifying the nature of this relationship is to determine whether speech sound processing abilities in infants and toddlers correlate with later language processing abilities (Trehub & Henderson, 1996). Thus, the principal aim of this project is to determine the relationship between the brain's speech discrimination abilities in the first few years of life and later language development. Event-related potentials (ERPs) will be used to provide an index of neural processes that underlie discrimination of short, phonetically similar, vowel contrasts (I vs. E and blp vs. bEp) by infants and toddlers between the ages of 3 and 12 months. We have chosen these vowel contrasts because children with poor language skills have difficulty processing brief vowels (preliminary study 1; Stark and Heinz, 1996; Leonard, et al., 1992). A sub-group of the infants will be from bilingual Spanish-English households, because research suggests that exposure to a different distribution of speech sounds and syllable structures during development will affect development of phonological categories. ERP measures, such as peak latency, amplitude, topography of components that index discrimination will be related to behavioral measures of speech and language competence obtained at 6, 12, 18, 24, and 36 months of age in a longitudinal study. In a cross-sectional design, we will examine changes in the ERP manifestations of brain discrimination and changes in behavioral discrimination of these speech contrasts from 3 months to 10 years of age and in adults. The goal of this cross-sectional investigation is to provide information about the relationship between brain and behavioral discrimination that we cannot obtain in the longitudinal design. The Specific Aims of this study are 1) To determine the relationship between the development of speech perception in the first year of life and later speech and language development measures; 2) To determine the relationship between brain and behavioral indices of discrimination of the vowel contrast from 3 months to 10 years of age, and 3) To determine the effect of the input (monolingual vs. bilingual) on speech discrimination using brain and behavioral indices of processing of these stimuli.