Word Learning in Language and Reading Impairment Subgroups

描述（由申请人提供）：特定语言障碍（SLI）影响超过7%的美国儿童，并与学术和工作相关问题的风险增加有关。SLI的一个关键特征是学习新单词的困难，但这种困难的本质却知之甚少。语音记忆和语义加工缺陷已被提出来解释SLI中的单词学习问题。虽然每一种提议都有一些证据，但以前的研究得出了不同的结果。鉴于这两个建议可能会提出不同的评估和干预方法，有一个关键需要了解的相对贡献的语音和语义赤字的单词学习SLI。因此，我们的研究计划的首要目标是澄清在SLI单词学习配置文件，并将这些配置文件与其他语言和认知配置文件，包括语音记忆和语义处理技能和赤字。过去研究结果的变异性的一个原因可能是使用了异质样本。许多（但不是所有）SLI儿童也有阅读障碍（SLI-DYS）。这些儿童在语音记忆方面有缺陷，通过非单词重复任务来测量，以及语义缺陷。然而，也有证据表明，在没有阅读障碍的情况下（仅SLI），SLI儿童有完整的非单词重复。过去的研究往往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的贡献，在四个小组：SLI只，DYS只，SLI-DYS，和典型的发展（TD）的儿童（具体目标1）的单词学习。我们假设SLI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）仔细检查四组学生的词汇学习过程来验证这一假设。此外，我们将确定2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2年级到3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，二年级的单词学习成绩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，语义技能，特别是将有助于预测 仅限SLI儿童。该项目在三个方面具有创新性：1）在SLI中单词学习的语音和语义方面的分离; 2）在SLI和SLI-DYS样本的分离;以及（3）使用实时ERP测量，补充离线任务。长期目标是为SLI制定更有效的评估和更有针对性的干预措施，这将对公共卫生结果产生强烈的积极影响。

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.