Word Learning in Language and Reading Impairment Subgroups

描述（由申请人提供）：特殊语言障碍（SLI）影响了超过7%的美国儿童，并与学业和工作相关问题的风险增加有关。特殊语言障碍的一个关键特征是难以学习新单词；然而，人们对这种困难的本质知之甚少。语音记忆和语义加工缺陷都被认为是特殊语言障碍中单词学习问题的原因。虽然每个建议都有一些证据，但之前的研究得出了不同的结果。鉴于这两种建议可能会提出不同的评估和干预方法，因此迫切需要了解语音和语义缺陷对特殊语言障碍中单词学习的相对贡献。因此，我们研究项目的首要目标是澄清特殊语言障碍的单词学习概况，并将这些概况与其他语言和认知概况联系起来，包括语音记忆和语义处理技能和缺陷。过去研究结果存在差异的一个原因可能是使用了异质样本。许多（但不是全部）患有特殊语言障碍的儿童也患有阅读障碍（SLI- dys）。这些孩子在语音记忆上有缺陷，通过非单词重复任务来衡量，以及语义上的缺陷。然而，也有证据表明，患有特殊语言障碍的儿童在没有阅读障碍的情况下（只有特殊语言障碍）具有完整的非单词重复。过去的研究倾向于将这两个样本混为一谈。为了解决这个问题，我们将研究语音和语义对单词学习的贡献，这四个亚组是：仅语障儿童、仅语障儿童、语障- dys儿童和典型发育（TD）儿童（具体目标1）。我们假设特殊语言障碍和阅读障碍的单词学习困难有不同的潜在原因。我们将通过使用标准化评估、认知行为任务和事件相关电位（ERP）仔细检查四组的单词学习过程来验证这一假设。此外，我们将确定二年级的单词学习表现如何预测一年后词汇知识和理解技能的增长（具体目标2）。从二年级到三年级的过渡标志着词汇和理解发展的重要转折点。我们预测，二年级的词汇学习表现将解释三年级词汇增长和理解的独特差异。我们进一步预测，尤其是语义技能，将有助于预测

DESCRIPTION (provided by applicant): Specific language impairment (SLI) affects over 7% of US children and is associated with increased risk of academic and work-related problems. A key feature of SLI is difficulty learning new words; yet the nature of this difficulty is poorly understood. Both phonological memory and semantic processing deficits have been proposed to account for word learning problems in SLI. While there is some evidence for each proposal, previous studies have yielded mixed results. Given that the two proposals may suggest different approaches to assessment and intervention, there is a critical need to understand the relative contributions of phonological and semantic deficits to word learning in SLI. Thus, an overarching aim of our research program is to clarify word learning profiles in SLI, and to relate these profiles to other language and cognitive profiles, including phonological memory and semantic processing skills and deficits. One reason for variability in past findings may be the use of heterogeneous samples. Many - but not all - children with SLI also have dyslexia (SLI-DYS). These children have deficits in phonological memory, as measured by nonword repetition tasks, as well as semantic deficits. However, there is also evidence that children with SLI in the absence of dyslexia (SLI-only) have intact nonword repetition. Past studies have tended to conflate the two samples. To address this issue, we will study phonological and semantic contributions to word learning in four subgroups: SLI-only, DYS-only, SLI-DYS, and typically developing (TD) children (Specific Aim 1). We hypothesize the word-learning difficulties in SLI and dyslexia have different underlying causes. We will test this hypothesis through careful examination of word learning processes in the four groups using standardized assessment, cognitive-behavioral tasks, and event-related potentials (ERP). In addition, we will determine how well word learning performance in grade 2 predicts growth in vocabulary knowledge and comprehension skills one year later (Specific Aim 2). The transition from grades 2 to 3 marks an important turning point in vocabulary and comprehension development. We predict that word learning performance in grade 2 will account for unique variance in vocabulary growth and comprehension in grade 3. We further predict that semantic skills, in particular, will help predict outcomes among SLI-only children. This project is innovative three ways: 1) in the separation of phonological and semantic aspects of word learning in SLI; 2) in the separation of SLI-only and SLI-DYS samples; and (3) in the use of real-time ERP measures, which complement offline tasks. The long-term goal is to develop more effective assessments and better-targeted interventions for SLI, which would have a strong positive impact on public health outcomes.