Relevance of auditory cortical maturation to early language acquisition

我的实验室研究儿童大脑中的声音处理，以及这与他们口语发展的关系。我们知道，同一年龄段的孩子在语言能力上各不相同。通过用脑电图测量听觉诱发电位（AEPs），我们了解到，同龄儿童的大脑对声音的反应也各不相同，这两种能力（听觉处理和语言）的复杂程度在某种程度上是相关的。先前的研究已经导致该领域的许多人假设大脑处理声音的能力会因果地影响儿童学习语言的方式。然而，研究尚未证实这种假设的影响方向。相反，大脑中更复杂的声音处理可能是儿童语言经验不断增长的结果，而我们之前的假设是错误的。 在这个新的研究项目中，我将纵向研究在早期语言习得过程中听觉和语言成熟度之间的影响方向。为了做到这一点，我和我的学员将使用一个我们验证过的指标，并将其与我之前的NSERC资金联系起来。这个指标是AEP年龄，这是一个估计的年龄相当于一个孩子的大脑对声音的反应。该度量比传统方法具有优势，因为它可以在最小参与的情况下在5分钟内响应于简单的音调并且通过不需要识别听觉脑波中的各个峰值的分析方法来获取。最后一个优势是关键，因为比较这个年龄段的儿童可能具有挑战性，因为这些峰的形状，大小，方向和存在可能会因儿童而异。使用这个指标，我们将收集年龄为12，18，24，30，36，48和62个月的儿童组的标准AEP，以估计个别儿童的反应的AEP年龄。然后，我们将跟踪一组18个月奥尔兹的婴儿的AEP年龄和语言能力的变化，直到他们达到48个月。这将使我们能够在一个纵向时期内考察这两个过程之间的影响方向。为了加强这项检查，我们不仅研究了表现出典型语言发展的儿童，还研究了那些迟到的人，以及那些持续拖延的人。了解影响力的方向很重要。如果听觉成熟度确实会影响语言成熟度，我们有理由在未来的研究中致力于更好地了解影响大脑听觉成熟的因素（如环境暴露和遗传学），这些影响的时间，以及操纵它们（如果可能）是否会影响语言发展。如果AEP年龄在预测早期语言习得的轨迹方面显示出希望，未来的研究可以检查临床翻译，以预测哪些儿童甚至在开始说话之前就有可能出现语言发展方面的问题。

My lab studies sound processing in children's brains and how this relates to their spoken language development. We know that children of the same age vary in their language skills. By measuring auditory-evoked potentials (AEPs) with electroencephalography, we have learned that children of the same age also vary in their brain responses to sounds, and that the sophistication of these two abilities (auditory processing and language) is somehow related. Prior research has led many in the field to assume that the brain's ability to process sounds causally influences how children learn language. However, research has yet to confirm this assumed direction of influence. Instead, it is possible that more sophisticated sound processing in the brain is a consequence of the child's growing experience with language, and that our prior assumptions have been wrong. In this new research program, I will longitudinally examine directions of influence between auditory and language sophistication during early language acquisition. To do this, my trainees and I will use a metric that we validated and linked to language with my prior NSERC funding. This metric is AEP-age, which is an estimate of the age equivalent of a child's brain response to sound. This metric has an advantage over traditional approaches because it can be acquired with minimal participation, in 5 minutes, in response to a simple tone, and via an analysis approach that does not require identifying individual peaks in the auditory brainwave. This last advantage is key because it can be challenging to compare children across this age range since these peaks can vary in shape, size, direction, and presence across children. Using this metric, we will gather normative AEPs from groups of children aged 12, 18, 24, 30, 36, 48 and 62 months to estimate the AEP-age of individual children's responses. Then we will track changes in both AEP-age and language ability in a group of 18 month olds until they reach 48 months. This will allow us to examine directions of influence between these two processes over a longitudinal period. To enhance this examination, we will not only study children showing typical language development but also late-talkers who catch up, and those with persistent delays. Understanding the direction of influence matters. If auditory sophistication indeed impacts language sophistication, we would be justified in dedicating future research efforts to better understanding the factors that influence auditory maturation in the brain (such as environmental exposures and genetics), the timing of these influences, and whether manipulating them (when possible) could impact language development. If AEP-age shows promise in predicting the trajectory of early language acquisition, future research could examine clinical translation into predicting which children are at risk for later problems in language development even before they begin talking.