Department of Radiology, University of Calgary, Calgary, AB, Canada; Biomedical Engineering Program, University of Calgary, Calgary, AB, Canada; Alberta Children's Hospital Research Institute and the Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.
Department of Radiology, University of Calgary, Calgary, AB, Canada; Alberta Children's Hospital Research Institute and the Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.
Dev Cogn Neurosci. 2019 Apr;36:100633. doi: 10.1016/j.dcn.2019.100633. Epub 2019 Mar 7.
Left temporal-parietal white matter structure is consistently associated with reading abilities in children. A small number of longitudinal studies show that development of this area over time is altered in children with impaired reading. However, it remains unclear how brain developmental patterns relate to specific reading skills such as fluency, which is a critical part of reading comprehension. Here, we examined white matter development trajectories in children with dysfluent reading (20 dysfluent and inaccurate readers, 36 dysfluent and accurate readers) compared to non-impaired readers (n = 14) over 18 months. We found typical age-related increases of fractional anisotropy (FA) in bilateral temporal-parietal areas in non-impaired readers, but a lack of similar changes in dysfluent readers. We also found steeper decreases of mean diffusivity (MD) in the right corona radiata and left uncinate fasciculus in dysfluent inaccurate readers compared to dysfluent accurate readers. Changes in diffusion parameters were correlated with changes in reading scores over time. These results suggest delayed white matter development in dysfluent readers, and show maturational differences between children with different types of reading impairment. Overall, these results highlight the importance of considering developmental trajectories, and demonstrate that the window of plasticity may be different for different children.
左侧颞顶叶白质结构与儿童的阅读能力密切相关。少数纵向研究表明，阅读障碍儿童的该区域随时间的发展发生了改变。然而，目前尚不清楚大脑发育模式与特定阅读技能（如流畅性）之间的关系，流畅性是阅读理解的关键部分。在这里，我们在 18 个月的时间内，比较了阅读不流畅的儿童（20 名不流畅且不准确的读者，36 名不流畅且准确的读者）与非受损读者（n=14）的白质发展轨迹。我们发现，在非受损读者中，双侧颞顶叶区域的各向异性分数（FA）随年龄的增长而增加，但在阅读不流畅的读者中，这种变化并不明显。我们还发现，与阅读不流畅且准确的读者相比，阅读不流畅且不准确的读者右侧放射冠和左侧钩束的平均弥散度（MD）下降更为陡峭。扩散参数的变化与随时间推移的阅读分数的变化相关。这些结果表明阅读不流畅的儿童的白质发育延迟，并显示出不同类型阅读障碍儿童之间存在成熟差异。总的来说，这些结果强调了考虑发展轨迹的重要性，并表明不同儿童的可塑性窗口可能不同。
