Prefrontal volume reductions commonly are demonstrated in ADHD, but the literature examining prefrontal volume in reading disorders (RD) is scant despite their also having executive functioning (EF) deficits. Furthermore, only a few anatomical studies have examined the frontal lobes in comorbid RD/ADHD, though they have EF deficits similar to RD and ADHD. Hence, we examined frontal gyri volume in children with RD, ADHD, RD/ADHD and controls, as well as their relationship to EF for gyri found to differ between groups. We found right inferior frontal (RIF) volume was smaller in ADHD, and smaller volume was related to worse behavioral regulation. Left superior frontal (LSF) volume was larger in RD than ADHD, and its size was negatively related to basic reading ability. Left middle frontal (LMF) volume was largest in RD/ADHD overall. Further, its volume was not related to basic reading nor behavioral regulation but was related to worse attentional control, suggesting some specificity in its EF relationship. When examining hypotheses on the etiology of RD/ADHD, RD/ADHD was commensurate with ADHD in RIF volume and both RD and ADHD in LSF volume (being midway between the groups), consistent with the common etiology hypothesis. Nevertheless, they also had an additional gyrus affected: LMF, consistent with the cognitive subtype hypothesis in its specificity to RD/ADHD. The few other frontal aMRI studies on RD/ADHD supported both hypotheses as well. Given this, future research should continue to focus on frontal morphology in its endeavors to find neurobiological contributors to the comorbidity between RD and ADHD.

中文翻译：

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额叶可能是注意力缺陷/多动障碍和阅读障碍合并症的潜在来源。

前额叶减少通常在ADHD中得到证实，但是尽管阅读障碍（RD）也具有执行功能（EF）缺陷，但检查前额叶阅读量（RD）的文献很少。此外，只有少数解剖学研究检查了合并RD / ADHD中的额叶，尽管它们的EF缺损类似于RD和ADHD。因此，我们检查了RD，ADHD，RD / ADHD和对照儿童的额回回体积，以及他们与EF的关系，发现两组之间回回的差异。我们发现多动症患者右下额叶（RIF）的体积较小，而较小的体积与行为调节较差有关。RD中左上额叶（LSF）的体积大于ADHD，其大小与基本阅读能力负相关。总体而言，左中额叶（LMF）体积最大的是RD / ADHD。进一步，它的体积与基本阅读或行为调节无关，但与注意力控制不佳有关，表明其EF关系具有一定的特异性。在检查有关RD / ADHD病因的假设时，RD / ADHD与RIF量中的ADHD和LSF量中的RD和ADHD（在组之间处于中间）相称，与常见病因假说相符。尽管如此，他们也有一个额外的回旋受到影响：LMF，与对RD / ADHD的特异性的认知亚型假设一致。关于RD / ADHD的其他少数额叶aMRI研究也支持这两种假设。鉴于此，未来的研究应继续关注额叶形态，以寻找导致RD与ADHD合并症的神经生物学因素。