Reading disorders are common in children and can impact academic success, mental health, and career prospects. Reading is supported by network of interconnected left hemisphere brain regions, including temporo-parietal, occipito-temporal, and inferior-frontal circuits. Poor readers often show hypoactivation and reduced gray matter volumes in this reading network, with hyperactivation and increased volumes in the posterior right hemisphere. We assessed gray matter development longitudinally in pre-reading children aged 2–5 years using magnetic resonance imaging (MRI) (N = 32, 110 MRI scans; mean age: 4.40 ± 0.77 years), half of whom had a family history of reading disorder. The family history group showed slower proportional growth (relative to total brain volume) in the left supramarginal and inferior frontal gyri, and faster proportional growth in the right angular, right fusiform, and bilateral lingual gyri. This suggests delayed development of left hemisphere reading areas in children with a family history of dyslexia, along with faster growth in right homologues. This alternate development pattern may predispose the brain to later reading difficulties and may later manifest as the commonly noted compensatory mechanisms. The results of this study further shows our understanding of structural brain alterations that may form the neurological basis of reading difficulties.

中文翻译：

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有阅读障碍家族史的预读儿童灰质发育改变

阅读障碍在儿童中很常见，会影响学业成功、心理健康和职业前景。阅读由相互连接的左半球大脑区域网络支持，包括颞顶叶、枕颞和下额叶回路。阅读能力差的阅读者经常在这个阅读网络中表现出低激活和灰质体积减少，右后半球过度激活和体积增加。我们使用磁共振成像 (MRI) 纵向评估了 2-5 岁阅读前儿童的灰质发育 ( N = 32, 110 次 MRI 扫描；平均年龄：4.40 ± 0.77 岁），其中一半有阅读障碍家族史。家族史组显示左侧缘上回和额下回的比例增长较慢（相对于总脑容量），而右侧角回、右梭状回和双侧舌回的比例增长较快。这表明有阅读障碍家族史的儿童左半球阅读区域发育迟缓，右侧同系物生长较快。这种交替的发展模式可能使大脑更容易出现以后的阅读困难，并可能在以后表现为常见的代偿机制。这项研究的结果进一步显示了我们对可能构成阅读困难的神经学基础的结构性大脑改变的理解。