Leonard Christiana, Eckert Mark, Given Barbara, Virginia Berninger, Eden Guinevere
Department of Neuroscience, University of Florida, Gainesville, FL 32605, USA.
Brain. 2006 Dec;129(Pt 12):3329-42. doi: 10.1093/brain/awl262. Epub 2006 Sep 29.
Developmental dyslexia (DD) and specific language impairment (SLI) are disorders of language that differ in diagnostic criteria and outcome. DD is defined by isolated reading deficits. SLI is defined by poor receptive and expressive oral language skills. Reading deficits, although prevalent, are not necessary for the diagnosis of SLI. An enduring question is whether these two disorders are qualitatively different or simply differ quantitatively along a dimension of severity. Here we address this problem by examining neuroanatomical correlates of reading and language in children with learning disabilities. We asked whether a quantitative anatomical risk index derived from previous work could predict behavioural profiles in a heterogeneous sample of 14 boys and 8 girls (11-16 years of age) with reading and language impairments. The results confirmed our predictions that (i) children with relatively smaller and symmetrical brain structures (negative risk indices) would have the severe comprehension impairments typical of SLI; (ii) children with larger, asymmetrical brain structures (positive risk indices) would have poor word reading in the presence of relatively preserved comprehension, a profile typical of DD; and (iii) the best performance would be seen in children with anatomical risk indices near zero (normal anatomy). Also, in confirmation of previous work, rapid automatic naming was not predicted by the anatomical risk index, but by anatomical measures derived from the frontal lobes. These results highlight the key significance of comprehension deficits in distinguishing DD from SLI. Reading impaired children with and without comprehension deficits appear to occupy neuroanatomical domains on the opposite sides of normal.
发育性阅读障碍（DD）和特定语言障碍（SLI）是语言障碍，在诊断标准和结果方面存在差异。DD由孤立的阅读缺陷定义。SLI由较差的接受性和表达性口语技能定义。阅读缺陷虽然普遍存在，但并非SLI诊断所必需。一个长期存在的问题是，这两种障碍在性质上是否不同，还是仅仅在严重程度维度上存在数量差异。在这里，我们通过研究学习障碍儿童阅读和语言的神经解剖学相关性来解决这个问题。我们询问，从先前工作中得出的定量解剖风险指数是否能够预测14名男孩和8名女孩（11 - 16岁）组成的异质样本中，有阅读和语言障碍者的行为特征。结果证实了我们的预测：（i）脑结构相对较小且对称（风险指数为负）的儿童会出现SLI典型的严重理解障碍；（ii）脑结构较大且不对称（风险指数为正）的儿童在理解相对保留的情况下单词阅读能力较差，这是DD的典型特征；（iii）解剖风险指数接近零（解剖结构正常）的儿童表现最佳。此外，正如先前工作所证实的，快速自动命名不是由解剖风险指数预测的，而是由额叶的解剖测量值预测的。这些结果突出了理解缺陷在区分DD和SLI中的关键意义。有和没有理解缺陷的阅读障碍儿童似乎占据了正常情况两侧的神经解剖学领域。
