The Neurodevelopmental Basis of Speech Discrimination

描述（由申请人提供）：许多研究已经报道了幼儿的语音处理缺陷和语言障碍之间的关联（例如，Tallal等人，1991年）。然而，这些缺陷之间的因果关系仍不清楚。澄清这种关系的性质的第一步是确定婴儿和幼儿的语音声音处理能力是否与后来的语言处理能力相关（Trehub &亨德森，1996）。因此，该项目的主要目的是确定大脑在生命最初几年的语音识别能力与后来的语言发展之间的关系。事件相关电位（ERP）将用于提供神经过程的指数，这些神经过程是3至12个月大的婴儿和幼儿区分短的、语音相似的元音对比（I与E和blp与bEp）的基础。我们之所以选择这些元音对比，是因为语言技能差的儿童难以处理简短的元音（初步研究1; Stark和海因茨，1996;伦纳德等人，1992年）。一个小组的婴儿将来自西班牙语和英语双语家庭，因为研究表明，在发育过程中暴露于不同的语音和音节结构分布将影响语音类别的发展。ERP测量，如峰值潜伏期，振幅，地形的组成部分，指数的歧视将相关的言语和语言能力的行为措施，在6个月，12个月，18个月，24个月和36个月的纵向研究。在一个横断面设计中，我们将研究从3个月到10岁和成年人的大脑歧视的ERP表现和行为歧视的变化。这项横断面调查的目的是提供我们在纵向设计中无法获得的关于大脑和行为歧视之间关系的信息。本研究的具体目的是：（1）确定出生后第一年言语知觉的发展与以后言语和语言发展测量之间的关系;（2）研究3个月~ 10岁儿童元音对比辨别的脑与行为指标之间的关系，和3）使用处理这些刺激的大脑和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.