Word Learning in Language and Reading Impairment Subgroups

描述(由申请人提供)：特殊语言障碍(SLI)影响着超过7%的美国儿童，并与学业和工作相关问题的风险增加有关。SLI的一个关键特征是难以学习新单词；然而，人们对这种困难的性质知之甚少。语音记忆缺陷和语义加工缺陷都被认为是SLI词汇学习问题的原因。虽然每个提议都有一些证据，但之前的研究得出了喜忧参半的结果。鉴于这两种建议可能提出了不同的评估和干预方法，因此有必要了解语音和语义缺陷对SLI词汇学习的相对贡献。因此，我们研究项目的一个主要目标是阐明SLI中的单词学习特征，并将这些特征与其他语言和认知特征联系起来，包括语音记忆和语义处理技能和缺陷。过去研究结果可变性的一个原因可能是使用了不同种类的样本。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衡量，以及语义缺陷。然而，也有证据表明，没有阅读障碍的SLI儿童(仅SLI)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，我们将在四个小组中研究语音和语义对单词学习的贡献：仅限SLI、仅限DYS、SLI-DYS和典型发展中(TD)儿童(具体目标1)。我们假设SLI和阅读困难症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)仔细检查这四组人的单词学习过程来检验这一假设。此外，我们将确定二年级的单词学习成绩对一年后词汇知识和理解技能增长的预测能力(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一个重要转折点。我们预测，二年级的单词学习成绩将解释三年级的词汇增长和理解的独特差异。我们进一步预测，语义技能将特别有助于预测 SLI独生子女的结局。这个项目有三个创新之处：1)在SLI中单词学习的语音和语义方面的分离；2)SLI-Only和SLI-DYS样本的分离；以及(3)实时ERP措施的使用，作为离线任务的补充。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大的积极影响。

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.