Studies published from 1980 through 2004, which explored intelligence and executive function outcomes in early-treated PKU, were included in the present meta-analysis. The objective of this study was to examine the degree of difference between early-treated PKU and unaffected control groups (primarily non-familial controls), known as effect size, for various components of measured intelligence (i.e., full-scale, verbal, performance, and “other”) and executive function (i.e., planning, working memory, inhibition, flexibility, and “other”). Secondly, in the case of heterogeneity among observed effect sizes, the moderator variables of “years since publication” and “measurement tools” were examined for their potential contribution to this heterogeneity. Thirty-three primary studies, with a total 200 outcomes meeting our inclusionary and exclusionary criteria, were meta-analyzed using Hedges g for effect size to correct for small samples in primary studies. The effect sizes for intelligence outcomes were “small” to “moderate” falling in the range of .20 to .42, with no significant heterogeneity among outcomes. Effect sizes for executive function and its various component processes were in the “moderate” and “large range” falling between .591 (planning) and 1.15 (flexibility). Significant heterogeneity among the executive function effect sizes was identified, and both “years since publication” and “measurement tools” were found to be significant moderators. Studies published more recently exhibited larger effect sizes, and particular executive function tasks demonstrated larger effect sizes than other tests. The results are discussed in terms of the contributions this meta-analysis makes to our understanding of neurocognitive outcomes in early-treated PKU, as well as suggestions for the conduct and reporting of future research in this area.

中文翻译：

---

苯丙酮尿症早期治疗神经认知结果的 25 年研究：智力和执行功能

本荟萃分析包括 1980 年至 2004 年发表的研究，这些研究探索了早期治疗的 PKU 的智力和执行功能结果。本研究的目的是检查早期治疗的 PKU 和未受影响的对照组（主要是非家族控制组）之间的差异程度，称为效应大小，用于测量智力的各个组成部分（即全面、言语、表现和“其他”）和执行功能（即计划、工作记忆、抑制、灵活性和“其他”）。其次，在观察到的效应大小之间存在异质性的情况下，检查了“发表年数”和“测量工具”这两个调节变量对这种异质性的潜在贡献。三十三个初级研究，总共有 200 个结果符合我们的纳入和排除标准，使用 Hedges g 对效应大小进行荟萃分析，以校正初级研究中的小样本。智力结果的影响大小从“小”到“中等”，范围在 0.20 到 0.42 之间，结果之间没有显着的异质性。执行功能及其各种组成过程的效果大小处于“中等”和“大范围”，介于 0.591（计划）和 1.15（灵活性）之间。确定了执行功能效应大小之间的显着异质性，并且发现“发表后的年数”和“测量工具”都是重要的调节因素。最近发表的研究显示出更大的效应量，特定的执行功能任务显示出比其他测试更大的效应量。