Language outcomes, mechanisms, and trajectories in adults with and without Developmental Language Disorder

摘要 发展性语言障碍(Development Language Disorder，DLD)的特点是学习和使用语言的能力有困难 是最常见的神经发育障碍之一(患病率为7-12%1，2)。尽管出现了一些问题 在童年时期，DLD会持续到成年3-6岁，并产生深远的负面影响。患有DLD的成年人不太可能 寻求大专教育7-9，可能有更长的一轮失业，并有更高的失业率 抑郁10.然而，对成年期DLD的研究严重不足。对语言配置文件的理解是 由于成年后的语言能力会影响幸福感、收入和工作表现，因此至关重要。此外，还有 显然有必要更好地了解成年人语言能力的调节机制 DLD。这样做将有助于解释DLD12-15(处理速度和工作记忆账户)和 在语言能力上暴露出更广泛的个体差异。审视竞争--激活 随着言语的展开，相互竞争的语言表征--是探索这些机制的理想途径。 竞争是语言的基本组成部分，在典型的成年人中有很好的记录16-19，而且关键的是， 竞争的不同方面可以与每个理论帐户20、21联系起来。我们的总体目标是 描述DLD在成年期的长期结果(目标1)并确定具体的认知机制 调解这些结果(目标2)。为了实现我们的目标，我们利用了一个大型的、预先存在的数据集和 参与者来自迄今为止DLD最全面的考试之一：爱荷华州纵向研究22。 我们将从这个历史队列中重新招募患有DLD(n=150)和典型语言(TL；n=250)的受试者，他们 现在是成年人(30-34岁)。在目标1中，我们利用了幼儿园的回溯性语言测量 通过10级和收集成年后新的结果测量来表征长期结果 DLD。我们预测，患有DLD的成年人在更复杂的语言技能上将与患有TL的成年人有所不同 以及更高层次的语言技能，这些技能对工作场所的沟通很重要。此外，我们预测， 范宁效应：一些患有DLD的儿童在成年后会“赶上”他们的TL同龄人，有些会表现出 下降，而其他人将显示稳定的轨迹。在目标2中，我们测量跨语言的实时竞争 视觉世界范式中使用眼球跟踪的形态和水平23。根据处理速度 帐户15，20，患有DLD的成年人可能比他们的TL同龄人更慢地激活竞争对手和靶子。根据 对于工作记忆账户21、24，患有DLD的成年人将显示出持续的竞争对手激活。 此外， 我们预测 这与竞争的动态(激活的速度和抑制竞争者的时机)有关 将解释成年人在不同能力范围内的语言结果的差异。拟议的工作将 代表了有(或没有)成年人语言能力的最大和最全面的特征 DLD到目前为止，介绍了DLD理论和语言处理的一般理论，并提供了基础 对成人DLD的预防和长期干预的临床模式的了解。

ABSTRACT Developmental Language Disorder (DLD) is characterized by difficulties in the ability to learn and use language and is one of the most common neurodevelopmental disorders (prevalence 7-12%1,2). Though problems emerge in childhood, DLD continues into adulthood3-6 and has profoundly negative effects. Adults with DLD are less likely to seek post-secondary education7-9, may have extended bouts of unemployment9, and have higher rates of depression10. Yet, DLD in adulthood is severely under-researched. An understanding of the language profile is crucial as language abilities in adulthood impact well-being, income, and job performance11. Additionally, there is a clear need to better understand the mechanisms that mediate language abilities in adults with and without DLD. Doing so will help explain theories of DLD12-15 (speed of processing and working memory accounts) and expose a wider range of individual differences in language ability. Examining competition – the activation of competing linguistic representations as speech unfolds – is an ideal approach to exploring these mechanisms. Competition is a fundamental component of language, is well-documented in typical adults16-19, and critically, distinct aspects of competition can be linked to each theoretical account20,21. Our overall objective is to characterize the long-term outcomes of DLD in adulthood (Aim 1) and to identify specific cognitive mechanisms mediating these outcomes (Aim 2). To address our objectives, we utilize a large, pre-existing dataset and participant pool from one of the most comprehensive examinations of DLD to date: the Iowa Longitudinal Study22. We will re-recruit subjects with DLD (n=150) and with typical language (TL; n=250) from this historic cohort, who are now adults (30–34 years old). In Aim 1, we leverage retrospective language measures from kindergarten through 10th grade and collect new outcome measures in adulthood to characterize the long-term outcomes of DLD. We predict that adults with DLD will diverge from adults with TL in language skills that are more complex and higher-level language skills that are important for communication in the workplace11. Further, we predict a fanning effect: some children with DLD will “catch up” to their TL peers in adulthood, some will show evidence of a decline, and others will show stable trajectories. In Aim 2, we measure real-time competition across language modality and level using eye-tracking in the Visual World Paradigm23. According to speed of processing accounts15,20, adults with DLD may be slower than their TL peers to activate competitors and targets. According to working memory accounts21,24, adults with DLD will show sustained competitor activation. Further, we predict that measures related to the dynamics of competition (speed of activation and timing of competitor suppression) will account for variation in language outcomes in adults across the ability spectrum. The proposed work would represent the largest and most comprehensive characterization of language abilities in adults with (and without) DLD to date, inform theories of DLD and general theories of language processing, and provide foundational knowledge toward clinical models of prevention and long-term intervention for adults with DLD.