Cognitive predictors of language impairment in Down syndrome

描述（申请人提供）：唐氏综合症（DS）患者的智力通常处于人口的最低2%，但他们的语言能力远远低于他们的智力。严重的语言限制对DS患者的生活功能有着深刻而广泛的影响。虽然已经做了很多工作来了解DS患者的语言能力模式，但对导致这种模式的潜在过程或机制的性质知之甚少。广泛的，长期的目标，拟议的研究是确定认知预测语言障碍的DS，特别是句法。我们预测，内隐学习和语音记忆的障碍共同导致这一群体的语言障碍。该研究采用了一种组合的比较/纵向设计，其中在时间1时对DS组（年龄10-21岁）和2个对照组（CA和混合病因ID）进行了检测，并在2年后的时间2时再次对DS组和混合ID组进行了检测。具体目标1是证明，除了已知的损害语音记忆，也有一个严重的损害，在DS的内隐学习。我们预计DS参与者表现更差比CA和ID组的措施，内隐学习和语音记忆。本研究还包括一个典型的发展轨迹，以评估内隐学习的DS和混合ID组。具体目标2是证明内隐学习和语音记忆障碍与DS中的语言障碍有关。如果是这样的话，那么（a）内隐学习和语音记忆将与DS的并发语言能力相关，（B）时间1的内隐学习和语音记忆将预测DS两年以上的语言发展速度。具体目标3是检验内隐学习对DS语言，尤其是句法影响的部分中介模型。我们认为，内隐学习直接影响语言，因为它限制了复杂的规则系统和语言习得所需的协变的收购，但也间接，通过语音记忆。对母语语音单位之间的共变的内隐学习不足会导致语音记忆的局限性，从而制约语言习得。我们将在两年内同时和纵向测试部分调解模式。

DESCRIPTION (provided by applicant): People with Down syndrome (DS) are usually in the lowest 2% of the population in intellectual ability, yet their language ability is far lower than their intellectual ability. Severe language limitations have a profound and pervasive impact on life functioning of people with DS. Though much work has been done to understand the pattern of language abilities in individuals with DS, little is known about the nature of the underlying processes or mechanisms that result in this pattern. The broad, long-term objective of the proposed research is to identify cognitive predictors of language impairment in DS, especially syntax. We predict that impairments in implicit learning and phonological memory together lead to impairments in language in this group. The study uses a combined comparative/longitudinal design in which a DS group, age 10-21, and 2 control groups (CA and mixed etiology ID) are tested at Time 1 and the DS and mixed ID groups are tested again 2 years later at Time 2. Specific Aim 1 is to demonstrate that, in addition to the known impairment in phonological memory, there is also a severe impairment in implicit learning in DS. We expect participants with DS to perform more poorly than CA and ID groups on measures of implicit learning and phonological memory. The study also includes a typical developmental trajectory to evaluate implicit learning in the DS and mixed ID groups. Specific Aim 2 is to demonstrate that implicit learning and phonological memory impairments are linked to language impairment in DS. If so, then (a) implicit learning and phonological memory will correlate with concurrent language ability in DS and (b) implicit learning and phonological memory at Time 1 will predict rate of language development over two years in DS. Specific Aim 3 is to test a partial mediation model of the influence of implicit learning on language in DS, especially syntax. We suggest that implicit learning affects language directly, because it limits the acquisition of complex rule systems and covariations necessary for language acquisition, but also indirectly, through phonological memory. Poor implicit learning of covariations among phonologic units in one's native language leads to limitations in phonological memory, which constrain language acquisition. We will test the partial mediation model concurrently and longitudinally over two years.