Phonetic learning in adults with and without language impairment

 描述（由申请人提供）：尽管几十年的辩论致力于特定语言障碍的病因，缺陷的起源尚未确定。标志性症状包括获得低感知显著性的语法语素的相对困难（伦纳德，2014），言语工作记忆差（Ellis-Weismer，1996），语言处理减慢（Friedrich，Weber，& Friederici，2004），以及难以识别噪音中的语音（齐格勒等人，2005年）。Joanisse和Sciedenberg（1998）假设，语音表征的不稳定性导致言语工作记忆的不良，从而导致语法习得的障碍。虽然这个框架占语音处理/感知缺陷，语音缺陷的起源仍然存在争议。一些人认为，表征质量差是由低水平听觉处理的差异引起的（麦克阿瑟& Bishop 2001，Wright et al. 1997），而另一些人（例如Ullman & Pierpont，2005）则提出了一种领域普遍的内隐学习缺陷。内隐学习的缺陷更好地解释了在听觉/语言领域之外的表现测量中观察到的差异（例如Lum，Conti-Ramsden，Morgan，& Ullman，2014）;然而，内隐学习的缺陷如何与建立语音表征有关尚不清楚。我们的实验室已经开发了一个实验方案，该方案检查了典型成年人在感知训练后对新（非母语）语音进行编码的时间过程（Earle & Myers，出版中，提交）。我们认为，训练后的睡眠在建立新的语音类别方面起着重要作用（参见Earle & Myers，2014，回顾）;因此，我们的兴趣不仅在于获取语音信息的初始阶段，而且在于这些信息在训练后的最初24小时内如何编码。在目前的建议中，我们扩展我们的工作，语音学习语言障碍的个人，以有助于语音赤字的记忆帐户。我们将评估参与者在训练前、训练后立即和一段时间的睡眠后感知非母语对比的能力。我们将进一步获得睡眠的基本测量，以确定睡眠持续时间的个体差异是否会影响睡眠后的表现。我们还打算收集电生理措施的敏感性训练的声音，以确保组之间观察到的差异不依赖于元语言任务的性能。这项研究将推进我们对记忆编码过程如何有助于语音学习的认识，并进一步了解语言障碍个体编码语音特征的机制。这个帐户可能会指导进一步研究的神经生物学基础的记忆缺陷SLI，最终目标是确定适当的补救/干预。因此，我们的项目目标中概述的研究指出了三个研究领域的潜在贡献：言语感知，记忆巩固和特定语言障碍。

 DESCRIPTION (provided by applicant): Despite decades of debate devoted to the etiology of Specific Language Impairment, the origin of deficit has yet to be identified. Hallmark symptoms include the relative difficulty to acquire grammatical morphemes of low perceptual salience (Leonard, 2014), poor verbal working memory (Ellis-Weismer, 1996), slowed language processing (Friedrich, Weber, & Friederici, 2004), and difficulty identifying speech in noise (Ziegler et al., 2005). Joanisse and Sciedenberg (1998) hypothesize that instability in phonological representations lead to poor verbal working memory, cascading to the impairment in the acquisition of grammar. While this framework accounts for speech processing/perceptual deficits, the origins of phonological deficit remain in debate. Some argue that poor representational quality arises from differences in low-level auditory processing (McArthur & Bishop 2001, Wright et al. 1997), while others (e.g. Ullman & Pierpont, 2005) propose a domain-general implicit learning deficit. A deficit in implicit learning better accounts for the differencs observed in performance measures outside the auditory/linguistic domain (e.g. Lum, Conti-Ramsden, Morgan, & Ullman, 2014); however, how a deficit in implicit learning relates to building phonological representations is not yet clear. Our lab has developed an experimental protocol that examines the time course of encoding of new (nonnative) speech sounds following perceptual training in typical adults (Earle & Myers, in press, submitted). We have argued that post-training sleep plays an important role in building new phonetic categories (see Earle & Myers, 2014, for review); thus, our interest has been not only in the initial phase of acquiring phonetic information, but in how that information is encoded during the initial 24 hours following training. In the current proposal, we extend our work on phonetic learning to individuals with language impairment in order to contribute a memory account of the phonological deficit. We will assess participants' ability to perceive a nonnative contrast before training, immediately aftr training, and after a period of sleep. We will further obtain a rudimentary measure of sleep to determine if individual differences in sleep duration affect post-sleep performance relative to immediate posttest. We also intend to gather electrophysiological measures of sensitivity to the trained sounds, to ensure that differences observed between groups are not dependent on metalinguistic task performance. The proposed research will advance our knowledge of how memory encoding processes contribute to speech sound learning, and further inform the mechanism of breakdown in encoding phonetic features in individuals with language impairment. This account may direct further research into the neurobiological underpinnings of the memory deficits in SLI, with the eventual goal of identifying an appropriate remediation/intervention. The studies outlined in our project aims therefore point to potential contributions to three areas of research: speech perception, memory consolidation, and Specific Language Impairment.