Developmental language disorders are characterized by a maturational trajectory that deviates or lags that of normal children. Given the wide variation in the rate of normal language development, diagnosis and classification of these disorders poses severe problems for the clinician. Our laboratory has been searching for anatomical signatures that could aid the development of a neurobiologically based classification. Quantitative analysis of the magnetic resonance imaging (MRI) brain scans of a series of samples of children and adults with reading and language disorders has identified two clusters with contrasting anatomical and reading profiles. Individuals with small symmetrical brain structures tend to have deficits in multiple domains of written and oral language whereas those with larger asymmetrical structures are more likely to have the isolated phonological deficits seen in adults with compensated dyslexia. Surprisingly, the anatomical risk factors that define these clusters do not form a continuum of increasing severity but deviate in opposite directions from normal. Individuals with moderate brain size and asymmetry typically demonstrate the best overall performance. Further research should determine if phonological impairments in the two clusters are associated with differing genetic and environmental risk factors requiring different types of intervention.

中文翻译：

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不对称和阅读障碍

发育性语言障碍的特点是其成熟轨迹偏离或滞后于正常儿童。鉴于正常语言发展的速度差异很大，这些疾病的诊断和分类给临床医生带来了严重的问题。我们的实验室一直在寻找有助于发展基于神经生物学的分类的解剖学特征。对一系列患有阅读和语言障碍的儿童和成人样本的磁共振成像 (MRI) 脑部扫描进行定量分析，确定了两个具有对比解剖和阅读特征的集群。具有较小对称大脑结构的个体往往在书面和口头语言的多个领域存在缺陷，而具有较大不对称结构的个体更可能存在代偿性阅读障碍成人中所见的孤立的语音缺陷。令人惊讶的是，定义这些集群的解剖学风险因素并没有形成严重程度增加的连续体，而是在相反的方向上偏离正常。具有中等大脑大小和不对称性的个体通常表现出最佳的整体表现。进一步的研究应该确定这两个集群中的语音障碍是否与需要不同类型干预的不同遗传和环境风险因素有关。定义这些集群的解剖风险因素不会形成严重程度增加的连续体，而是以相反的方向偏离正常。具有中等大脑大小和不对称性的个体通常表现出最佳的整体表现。进一步的研究应该确定这两个集群中的语音障碍是否与需要不同类型干预的不同遗传和环境风险因素有关。定义这些集群的解剖风险因素不会形成严重程度增加的连续体，而是以相反的方向偏离正常。具有中等大脑大小和不对称性的个体通常表现出最佳的整体表现。进一步的研究应该确定这两个集群中的语音障碍是否与需要不同类型干预的不同遗传和环境风险因素有关。