Are Frontal Lobe Size and Executive Dysfunction Contributors to ADHD AND Dyslexia

描述（由申请人提供）：阅读障碍儿童通常表现为语音加工不良。然而，人们越来越接受神经发育障碍可能最好的解释是多因子模型，其中包括其他常见的缺陷。其中一个缺陷就是执行功能障碍。在20世纪80年代，人们认识到许多患有阅读障碍的儿童都有执行功能障碍；然而，当研究人员开始更一致地研究语音处理时，对这一领域的研究在很大程度上被搁置了。因此，关于阅读障碍的执行功能障碍，特别是它与额叶结构的关系，仍有许多未知之处。阅读障碍和多动症有很高的合并症，执行功能障碍在多动症儿童中很常见。因此，确定执行功能障碍和非典型前额叶结构是否可能在这两种疾病之间共享贡献者是有意义的。该项目将包括100名8-12岁的儿童：25名患有阅读障碍，25名患有ADHD， 25名患有阅读障碍/ADHD共病，25名正常发展的对照组。所有受试者都将参与对其执行功能的神经心理学评估，并进行结构MRI扫描。因子分析将用于确定执行功能的潜在变量。以下额叶区域将被追踪到：前扣带和后扣带、中央前回、眶额回、额叶内侧皮层以及额叶上、中、下回。使用MANCOVA，我们假设患有阅读障碍和ADHD的儿童在流畅性、移位性和言语工作记忆方面有共同的缺陷。多动症在抑制和视觉工作记忆方面也会有缺陷。此外，假设两组的右侧额下回和左侧眶额回都比对照组小。相比之下，多动症患者的右额上回、额叶内侧皮层和右前扣带比阅读障碍和对照组要小。在阅读障碍和多动症患者中，当前额叶区域崩溃时，双侧的灰质会减少，尤其是在右半球。此外，多动症患者左侧前额叶白质体积也会减少。这项研究将通过提供有助于诊断和干预的知识，使患有阅读障碍和多动症的儿童受益。例如，通过更好地了解阅读障碍和多动症的生物学相关性，可能比传统的行为技术提供更快速的诊断。此外，早期诊断将允许更早地进行干预，早期干预与较晚开始治疗相比具有更好的结果。

DESCRIPTION (provided by applicant): Children with dyslexia frequently present with poor phonological processing. However, it is becoming accepted that neurodevelopmental disorders may be best explained by a poly-factorial model which includes other common deficits as well. One such deficit is executive dysfunction. In the 1980s it was recognized that many children with dyslexia have executive dysfunction; however, research into this area largely fell by the wayside when researchers began examining phonological processing more consistently. As a result, much remains unknown about executive dysfunction in dyslexia, especially in terms of how it relates to frontal lobe structure. Dyslexia and ADHD share a high comorbidity, and executive dysfunction is common in children with ADHD. Thus, it is of interest to determine if executive dysfunction and atypical prefrontal structure may be shared contributors between the two disorders. This project will include 100 children, ages 8-12 years: 25 with dyslexia, 25 with ADHD, 25 with comorbid dyslexia/ADHD, and 25 typically developing controls. All subjects will participate in a neuropsychological evaluation of their executive functioning along with a structural MRI scan. Factor analysis will be used to determine latent variables of executive functions. The following frontal regions will be traced: anterior and posterior cingulate, precentral gyrus, orbitofrontal gyrus, mesial frontal cortex, and the superior, middle, and inferior frontal gyri. Using MANCOVA It is hypothesized that children with dyslexia and ADHD will share deficits in fluency, shift, and verbal working memory. ADHD will also have deficits in inhibition and visual working memory. Moreover, it is hypothesized that the right inferior frontal and left orbitofrontal gyri will be smaller in both groups compared to controls. In contrast, the right superior frontal gyrus, mesial frontal cortex, and right anterior cingulate will be smaller in ADHD than dyslexia and controls. When collapsing across prefrontal regions, gray matter will be reduced bilaterally in dyslexia and ADHD, particularly in the right hemisphere. In addition, left prefrontal white matter volume will be reduced in ADHD. This study will benefit children with dyslexia and ADHD by providing knowledge that may aid diagnosis and intervention. For example, by having a better knowledge of the biological correlates of dyslexia and ADHD, a more rapid diagnosis may be possible than is provided by traditional behavioral techniques. Furthermore, earlier diagnosis will allow for earlier placement in intervention, and early intervention is linked with better outcome than treatment started later. PUBLIC HEALTH RELEVANCE: Developmental dyslexia and ADHD are two of the most prevalent childhood disorders. They also have a high rate of co-occurrence. This project will examine executive functioning (various skills/abilities which contribute to goal-directed behavior) and structure of the front aspect of the brain to see if they may be related to both dyslexia and ADHD.