CAS Key Laboratory of Behavioral Science, Center for Brain Science and Learning Difficulties, Institute of Psychology，Chinese Academy of Sciences, Beijing, China.
Department of Psychology, University of Chinese Academy of Sciences, Beijing, China.
Dev Sci. 2022 Mar;25(2):e13161. doi: 10.1111/desc.13161. Epub 2021 Aug 6.
Abundant behavioral studies have demonstrated high comorbidity of reading and handwriting difficulties in developmental dyslexia (DD), a neurological condition characterized by unexpectedly low reading ability despite adequate nonverbal intelligence and typical schooling. The neural correlates of handwriting deficits remain largely unknown; however, as well as the extent that handwriting deficits share common neural bases with reading deficits in DD. The present work used functional magnetic resonance imaging to examine brain activity during handwriting and reading tasks in Chinese dyslexic children (n = 18) and age-matched controls (n = 23). Compared to controls, dyslexic children exhibited reduced activation during handwriting tasks in brain regions supporting sensory-motor processing (including supplementary motor area and postcentral gyrus) and visual-orthography processing (including bilateral precuneus and right cuneus). Among these regions, the left supplementary motor area and the right precuneus also showed a trend of reduced activation during reading tasks in dyslexics. Moreover, increased activation was found in the left inferior frontal gyrus and anterior cingulate cortex in dyslexics, which may reflect more efforts of executive control to compensate for the impairments of motor and visual-orthographic processing. Finally, dyslexic children exhibited aberrant functional connectivity among brain areas for cognitive control and sensory-motor processes during handwriting tasks. Together, these findings suggest that handwriting deficits in DD are associated with functional abnormalities of multiple brain regions implicated in motor execution, visual-orthographic processing, and cognitive control, providing important implications for the diagnosis and treatment of dyslexia.
大量行为研究表明，发展性阅读障碍（DD）患者的阅读和书写困难存在高度共病性，DD 是一种神经发育障碍，其特征是阅读能力异常低下，尽管非言语智力和典型教育水平正常。书写缺陷的神经相关性仍知之甚少；然而，DD 患者的书写缺陷与阅读缺陷在多大程度上共享共同的神经基础仍不清楚。本研究使用功能磁共振成像技术，对 18 名中国阅读障碍儿童和 23 名年龄匹配的对照组儿童在书写和阅读任务中的大脑活动进行了研究。与对照组相比，阅读障碍儿童在书写任务中，大脑中支持感觉运动处理（包括辅助运动区和中央后回）和视觉正字法处理（包括双侧楔前叶和右侧楔叶）的区域的活动减少。在这些区域中，左辅助运动区和右楔前叶在阅读任务中也表现出阅读障碍者活动减少的趋势。此外，阅读障碍者的左额下回和前扣带回的活动增加，这可能反映了执行控制的更多努力，以补偿运动和视觉正字法处理的损伤。最后，阅读障碍儿童在书写任务中表现出认知控制和感觉运动过程中大脑区域之间的异常功能连接。总之，这些发现表明，DD 患者的书写缺陷与涉及运动执行、视觉正字法处理和认知控制的多个大脑区域的功能异常有关，这对阅读障碍的诊断和治疗具有重要意义。
