Speech in Autism and Neurodevelopmental Disorders Lab, Massachusetts General Hospital Institute of Health Professions, 36 1st Avenue, Boston, MA, 02129, USA.
Department of Neurology, Harvard Medical School, Boston, USA.
J Neurodev Disord. 2022 Jun 11;14(1):36. doi: 10.1186/s11689-022-09443-z.
Speech is the most common modality through which language is communicated, and delayed, disordered, or absent speech production is a hallmark of many neurodevelopmental and genetic disorders. Yet, speech is not often carefully phenotyped in neurodevelopmental disorders. In this paper, we argue that such deep phenotyping, defined as phenotyping that is specific to speech production and not conflated with language or cognitive ability, is vital if we are to understand how genetic variations affect the brain regions that are associated with spoken language. Speech is distinct from language, though the two are related behaviorally and share neural substrates. We present a brief taxonomy of developmental speech production disorders, with particular emphasis on the motor speech disorders childhood apraxia of speech (a disorder of motor planning) and childhood dysarthria (a set of disorders of motor execution). We review the history of discoveries concerning the KE family, in whom a hereditary form of communication impairment was identified as childhood apraxia of speech and linked to dysfunction in the FOXP2 gene. The story demonstrates how instrumental deep phenotyping of speech production was in this seminal discovery in the genetics of speech and language. There is considerable overlap between the neural substrates associated with speech production and with FOXP2 expression, suggesting that further genes associated with speech dysfunction will also be expressed in similar brain regions. We then show how a biologically accurate computational model of speech production, in combination with detailed information about speech production in children with developmental disorders, can generate testable hypotheses about the nature, genetics, and neurology of speech disorders.
Though speech and language are distinct, specific types of developmental speech disorder are associated with far-reaching effects on verbal communication in children with neurodevelopmental disorders. Therefore, detailed speech phenotyping, in collaboration with experts on pediatric speech development and disorders, can lead us to a new generation of discoveries about how speech development is affected in genetic disorders.
言语是语言交流最常见的方式，语言产生延迟、紊乱或缺失是许多神经发育和遗传障碍的标志。然而，在神经发育障碍中，言语通常没有被仔细表型化。在本文中，我们认为，如果我们要了解遗传变异如何影响与口语相关的大脑区域，这种深入的表型分析（定义为专门针对言语产生的表型分析，而不是与语言或认知能力混淆）是至关重要的。言语有别于语言，尽管两者在行为上相关，并共享神经基础。我们提出了一个简要的发育性言语产生障碍分类法，特别强调了运动性言语障碍——儿童言语失用（运动计划障碍）和儿童构音障碍（一组运动执行障碍）。我们回顾了 KE 家族的发现历史，在该家族中，一种遗传性的交流障碍被确定为儿童言语失用，并与 FOXP2 基因功能障碍有关。这个故事展示了深入表型分析言语产生在言语和语言遗传学这一开创性发现中的重要性。与言语产生相关的神经基础与 FOXP2 表达之间存在相当大的重叠，这表明与言语功能障碍相关的其他基因也将在类似的大脑区域表达。然后，我们展示了如何结合儿童发育障碍中言语产生的详细信息，使用生物上准确的言语产生计算模型来生成关于言语障碍的性质、遗传学和神经学的可测试假设。
尽管言语和语言是不同的，但特定类型的发育性言语障碍与神经发育障碍儿童的言语交流有着深远的影响。因此，详细的言语表型分析，与儿科言语发展和障碍专家合作，可以引导我们发现更多关于遗传障碍如何影响言语发展的新发现。
