The Neurodevelopmental Basis of Speech Discrimination

描述（由申请人提供）：大量研究报告了幼儿言语处理缺陷和语言障碍之间的联系（如Tallal等，1991）。然而，这些缺陷之间的因果关系尚不清楚。澄清这种关系的第一步是确定婴幼儿的语音处理能力是否与后期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生命最初几年大脑的语言识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 - 12个月的婴幼儿辨别短的、语音相似的、元音对比（I vs. E和blp vs. 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短元音方面存在困难（初步研究1；Stark and Heinz, 1996; Leonard, et al, 1992）。婴儿的一个小组将来自西班牙语-英语双语家庭，因为研究表明，在发育过程中暴露于不同的语音分布和音节结构将影响语音类别的发展。在一项纵向研究中，在6、12、18、24和36个月大时，ERP测量，如峰潜伏期、振幅、表征歧视的成分地形，将与言语和语言能力的行为测量相关联。在横断面设计中，我们将研究从3个月到10岁以及成人中这些语言对比的大脑歧视和行为歧视的ERP表现的变化。这项横断面研究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措施之间的关系；2)研究3个月~ 10岁儿童元音对比辨别的大脑和行为指标之间的关系；3)利用刺激处理的大脑和行为指标，确定单语和双语输入对言语辨别的影响。

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.