Findings of executive functioning deficits in Tourette syndrome (TS) have so far been inconsistent, possibly due to methodological challenges of previous studies, such as the use of small sample sizes and not accounting for comorbid attention-deficit/hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD), or medication use. We aimed to address these issues by examining several areas of executive functioning (response inhibition, attentional flexibility, cognitive control, and working memory) and psychomotor speed in 174 8-to-12-year-old children with TS [n = 34 without (TS-ADHD) and n = 26 with comorbid ADHD (TS+ADHD)], ADHD without tics (ADHD-TS; n = 54), and healthy controls (n = 60). We compared executive functioning measures and psychomotor speed between these groups and related these to ADHD severity across the whole sample, and tic severity across the TS groups. Children with TS+ADHD, but not TS-ADHD, made more errors on the cognitive control task than healthy children, while TS-ADHD had a slower psychomotor speed compared to healthy controls. The ADHD group showed impairment in cognitive control and working memory versus healthy controls. Moreover, higher ADHD severity was associated with poorer cognitive control and working memory across all groups; there was no relation between any of the executive functioning measures and tic severity. OCD severity or medication use did not influence our results. In conclusion, we found little evidence for executive function impairments inherent to TS. Executive function problems appear to manifest predominantly in relation to ADHD symptomatology, with both cross-disorder and unique features of neuropsychological functioning when cross-comparing TS and ADHD.

中文翻译：

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抽动秽语综合征和注意缺陷/多动障碍儿童的执行功能：交叉障碍还是独特的障碍？

迄今为止，在Tourette综合征（TS）中执行功能缺陷的发现并不一致，这可能是由于先前研究的方法学挑战，例如使用小样本量且未考虑合并症，注意力不足/多动症（ADHD），强迫症-强迫症（OCD）或药物使用。我们旨在通过检查174名8到12岁TS患儿[n = 34，没有（ TS-ADHD）和n = 26，合并共病ADHD（TS + ADHD）]，无抽动的ADHD（ADHD-TS； n = 54）和健康对照组（n = 60）。我们比较了这两个小组之间的执行功能指标和心理运动速度，并将其与整个样本中的ADHD严重程度相关联，TS组之间的抽动和抽动严重程度。患有TS + ADHD而不是TS-ADHD的儿童在认知控制任务上比健康儿童犯了更多错误，而与健康对照组相比，TS-ADHD的精神运动速度较慢。与健康对照组相比，ADHD组表现出认知控制和工作记忆受损。此外，ADHD的严重程度高与所有组的认知控制和工作记忆差有关。执行功能的任何措施与抽动的严重程度之间没有关系。强迫症严重程度或药物使用不会影响我们的结果。总之，我们几乎没有发现TS固有的执行功能受损的证据。执行功能问题似乎主要表现为多动症的症状，