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

摘要 发展性语言障碍（DLD）的特点是学习和使用语言的能力困难 并且是最常见的神经发育障碍之一（患病率7- 1,2%1，2）。虽然问题出现了 在儿童时期，DLD持续到成年3 -6，并具有深刻的负面影响。成人DLD患者不太可能 寻求中学后教育7 -9，可能会延长失业期9， 抑郁症10.然而，成人DLD的研究严重不足。对语言配置文件的理解是 这一点至关重要，因为成年期的语言能力会影响福祉、收入和工作表现11。此外，在 显然需要更好地了解调节成人语言能力的机制， DLD。这样做将有助于解释DLD 12 -15理论（处理速度和工作记忆帐户）， 揭示了语言能力的更大范围的个体差异。审查竞争-激活 竞争的语言表现作为语音展开-是一个理想的方法来探索这些机制。 竞争是语言的一个基本组成部分，在典型的成年人16 -19中得到了很好的证明， 竞争的不同方面可以与每个理论账户联系起来20、21。我们的总体目标是 描述成年期DLD的长期结局（目标1），并确定特定的认知机制 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， 来自迄今为止最全面的DLD检查之一的参与者池：爱荷华州纵向研究22。 我们将从该历史队列中重新招募DLD（n=150）和典型语言（TL; n=250）受试者， 现在是成年人（30-34岁）。在目标1中，我们利用幼儿园的回顾性语言测量 到10年级，并收集成年后的新结果指标，以表征 DLD。我们预测，成人DLD与成人TL在语言技能方面会有差异， 和更高层次的语言技能，这对工作场所的沟通很重要11。此外，我们预测A 扇形效应：一些患有DLD的儿童在成年后会“赶上”他们的TL同龄人，一些会显示出 一个下降，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动跟踪的模态和水平23.根据处理速度 15、20，DLD成年人激活竞争对手和目标的速度可能比TL同龄人慢。根据 对于工作记忆账户21，24，患有DLD的成年人将显示持续的竞争者激活。 此外，本发明还 我们预测 与竞争动态有关的措施（激活速度和抑制竞争者的时间） 将解释不同能力范围的成年人语言结果的差异。拟议的工作将 代表了成人语言能力的最大和最全面的表征（和没有） DLD的发展为DLD理论和语言处理的一般理论提供了基础， 对成人DLD预防和长期干预的临床模型的知识。

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.