Predicting language processing efficiency in preterm children: Social-environmental and neuro-biological factors

每年在美国，超过十分之一的儿童早产（PT）。大约一半的非常 早产存活者，出生时妊娠< 32周，发展语言学习障碍， 发现得晚，使儿童在一生中面临很大的不良后果的风险。我们之前的资助 （HD 069150）令人信服地证明，在18个月的眼睛中评估的语言处理效率- 跟踪范式，称为边听边看（LWL），比 标准化测试和家长报告18个月时语言处理速度更快的PT儿童 在54个月时，在语言和非语言技能方面都表现出优势。我们的下一步是及早了解 预测PT儿童的语言处理效率。在本次更新中，我们入组了PT新生儿（n = 140） 来自两个语言群体，主要是英语和西班牙语家庭，以增加我们的多样性， 抽样调查，以提高普遍性。我们评估了12个月时的社会环境预测因素（婴儿 环境）和18个月（幼儿环境）使用儿童语言的全天录音 环境和自然主义的实验室观察的儿童互动。我们评估神经生物学 预测因子，关注新生儿期（新生儿扫描）和12个月时的白色物质显微结构 （婴儿扫描）。我们使用两种互补类型的MRI扫描来评估白色物质轴突特性，并 髓鞘含量在18个月时，主要结果指标是LWL任务中的语言处理速度， 孩子将目光转移到刚刚命名的物体的图片上所花费的时间。家长报告 词汇量和语言发展标准化测试的分数是次要的衡量标准。我们的目标 （1）确定婴儿和/或幼儿环境的特性是否预测语言处理速度 和次要结果在PT儿童从两个语言组;（2）确定是否属性的白色 从新生儿和/或婴儿MRI扫描评估的物质通路，预测语言处理速度， 次要结局，考虑语言组、临床变量和其他协变量后;（3） 研究社会环境因素和白色物质发育对语言的影响 处理速度在这个不同的样本出生的儿童PT。我们的主要假设是， 语言学习环境和语言处理速度是由白色物质的变化介导的 发展，这表明支持性的学习环境影响语言成果，因为学习 环境促进了白色物质微观结构的发展。证明白色物质 变化介导的社会环境因素对语言结果的关联提供了一个明确的 人脑中经验依赖性可塑性的例子。这一发现将代表一个理论 为跨语言群体的PT儿童的学习和发展模式做出贡献，并将为 临床实践和早期干预的PT儿童谁是在高风险的语言效果差。

Each year in the U.S., more than one in 10 children are born preterm (PT). Approximately half of very preterm survivors, born at < 32 weeks’ gestation, develop language-based learning impairments that may be discovered late and put children at substantial risk for poor outcomes throughout their lives. Our previous grant (HD069150) convincingly demonstrated that language processing efficiency, assessed at 18 months in an eye- tracking paradigm, called looking-while-listening (LWL), was more predictive of long-term outcomes than standardized tests and parent reports. PT children who were faster at language processing at 18 months showed advantages in both verbal and non-verbal skills at 54 months. Our next step is to understand early predictors of language processing efficiency in PT children. In this renewal, we enroll PT neonates (n = 140) from two language groups, primarily English- and primarily Spanish families, to increase the diversity of our sample and to improve generalizability. We assess social-environmental predictors at 12 months (infant environment) and 18 months (toddler environment) using day-long audio recordings of the child’s language environment and naturalistic laboratory observations of caregiver-child interactions. We assess neurobiological predictors, focusing on white matter microstructure, in the neonatal period (neonatal scans) and at 12 months (infant scans). We use two complementary types of MRI scans to assess white matter axonal properties and myelin content. At 18 months, the primary outcome measure is language processing speed in the LWL task, the time it takes the child to shift eye gaze to the picture of an object that was just named. Parent reports of vocabulary and scores on a standardized test of language development are secondary measures. Our aims are to: (1) determine if properties of the infant and/or toddler environments predict language processing speed and secondary outcomes in PT children from the two language-groups; (2) determine if properties of white matter pathways, assessed from neonatal and/or infant MRI scans, predict language processing speed and secondary outcomes, after consideration of language group, clinical variables, and other covariates; and (3) investigate the contributions of social-environmental factors and white matter development on language processing speed in this diverse sample of children born PT. Our main hypothesis is that relations between language learning environments and language processing speed are mediated by changes in white matter development, suggesting that supportive learning environments impact language outcomes because learning environments advance the development of white matter microstructure. The demonstration that white matter change mediates the association of social-environmental factors on language outcomes provides a clear example of experience-dependent plasticity in the human brain. This finding would represent a theoretical contribution to models of learning and development in PT children across language groups and would inform clinical practice and early intervention for PT children who are at high risk for poor language outcomes.