BACKGROUND Dyslexia and Attention-deficit/hyperactivity disorder (ADHD) are highly comorbid neurodevelopmental disorders (estimates of 25-40% bidirectional comorbidity). Previous work has identified strong genetic and cognitive overlap between the disorders, but neural overlap is relatively unexplored. This study is a systematic meta-analysis of existing voxel-based morphometry studies to determine whether there is any overlap in the gray matter correlates of both disorders. METHODS We conducted anatomic likelihood estimate (ALE) meta-analyses of voxel-based morphometry studies in which individuals with dyslexia (15 studies; 417 cases, 416 controls) or ADHD (22 studies; 898 cases, 763 controls) were compared to typically developing controls. We generated ALE maps for dyslexia vs. controls and ADHD vs. controls using more conservative (p < .001, k = 50) and more lenient (p < .005, k = 50) thresholds. To determine the overlap of gray matter correlates of dyslexia and ADHD, we examined the statistical conjunction between the ALE maps for dyslexia vs. controls and ADHD vs. controls (false discovery rate [FDR] p < .05, k = 50, 5000 permutations). RESULTS Results showed largely distinct gray matter differences associated with dyslexia and ADHD. There was no evidence of statistically significant gray matter overlap at our conservative threshold, and only one region of overlap in the right caudate at our more lenient threshold. Reduced gray matter in the right caudate may be relevant to shared cognitive correlates in executive functioning and/or procedural learning. The more general finding of largely distinct regional differences in gray matter between dyslexia and ADHD suggests that other neuroimaging modalities may be more sensitive to overlapping neural correlates, and that current neuroimaging recruitment approaches may be hindering progress toward uncovering neural systems associated with comorbidity. CONCLUSIONS The current study is the first to meta-analyze overlap between gray matter differences in dyslexia and ADHD, which is a critical step toward constructing a multi-level understanding of this comorbidity that spans the genetic, neural, and cognitive levels of analysis.

中文翻译：

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阅读障碍和多动症之间是否存在共同的神经关联？基于体素的形态测量研究的荟萃分析。

背景阅读障碍和注意力缺陷/多动障碍 (ADHD) 是高度共病的神经发育障碍（估计有 25-40% 双向共病）。之前的工作已经发现这些疾病之间存在很强的遗传和认知重叠，但神经重叠相对尚未被探索。这项研究是对现有基于体素的形态测量研究的系统荟萃分析，以确定两种疾病的灰质相关性是否存在重叠。方法 我们对基于体素的形态测量研究进行了解剖似然估计 (ALE) 荟萃分析，其中将患有阅读障碍的个体（15 项研究；417 例，416 名对照）或 ADHD（22 项研究；898 例，763 名对照）与典型发育中的个体进行比较。控制。我们使用更保守（p < .001，k = 50）和更宽松（p < .005，k = 50）阈值生成阅读障碍与对照以及 ADHD 与对照的 ALE 地图。为了确定与阅读障碍和 ADHD 相关的灰质重叠，我们检查了阅读障碍与对照以及 ADHD 与对照的 ALE 图之间的统计关联（错误发现率 [FDR] p < .05，k = 50，5000 个排列）。结果 结果显示，与阅读障碍和注意力缺陷多动症相关的灰质差异在很大程度上是明显的。在我们保守的阈值下，没有证据表明统计上显着的灰质重叠，并且在我们更宽松的阈值下，右侧尾状核中只有一个区域重叠。右侧尾状核灰质的减少可能与执行功能和/或程序学习中的共享认知相关性有关。阅读障碍和多动症之间的灰质存在明显的区域差异这一更普遍的发现表明，其他神经影像学模式可能对重叠的神经相关性更敏感，并且当前的神经影像学招募方法可能阻碍了揭示与共病相关的神经系统的进展。结论本研究首次对阅读障碍和多动症灰质差异之间的重叠进行荟萃分析，这是构建对这种跨越遗传、神经和认知分析水平的共病的多层次理解的关键一步。