Phyllis Green and Randolph Cōwen Institute for Pediatric Neuroscience, NYU Child Study Center, New York University Langone Medical Center, One Park Avenue, 8th floor, New York, NY, 10016, USA.
Eur Child Adolesc Psychiatry. 2014 Feb;23(2):69-79. doi: 10.1007/s00787-013-0428-4. Epub 2013 May 29.
Despite the common co-occurrence of symptoms of attention deficit hyperactivity disorder (ADHD) in individuals with autism spectrum disorders (ASD), the underlying mechanisms are under-explored. A potential candidate for investigation is response time intra-subject variability (RT-ISV), a hypothesized marker of attentional lapses. Direct comparisons of RT-ISV in ASD versus ADHD are limited and contradictory. We aimed to examine whether distinct fluctuations in RT-ISV characterize children with ASD and with ADHD relative to typically developing children (TDC). We applied both a priori-based and data-driven strategies to RT performance of 46 children with ASD, 46 with ADHD, and 36 TDC (aged 7-11.9 years). Specifically, we contrasted groups relative to the amplitude of four preselected frequency bands as well as to 400 frequency bins from 0.006 to 0.345 Hz. In secondary analyses, we divided the ASD group into children with and without substantial ADHD symptoms (ASD(+) and ASD(-), respectively). Regardless of the strategy employed, RT-ISV fluctuations at frequencies between 0.20 and 0.345 Hz distinguished children with ADHD, but not children with ASD, from TDC. Children with ASD(+) and those with ADHD shared elevated amplitudes of RT-ISV fluctuations in frequencies between 0.18 and 0.345 Hz relative to TDC. In contrast, the ASD(-) subgroup did not differ from TDC in RT-ISV frequency fluctuations. RT-ISV fluctuations in frequencies 0.18-0.345 Hz (i.e., periods between 3 and 5 s) are associated with ADHD symptoms regardless of categorical diagnosis and may represent a biomarker. These results suggest that children with ADHD and those with ASD(+) share common underlying pathophysiological mechanisms of RT-ISV.
尽管自闭症谱系障碍（ASD）个体中经常共同出现注意力缺陷多动障碍（ADHD）的症状，但潜在的机制仍未得到充分探索。一个潜在的候选研究对象是反应时个体内变异性（RT-ISV），它是注意力不集中的假设标志物。ASD 与 ADHD 中 RT-ISV 的直接比较有限且相互矛盾。我们旨在研究 ASD 和 ADHD 儿童相对于典型发育儿童（TDC）的 RT-ISV 是否存在明显的波动特征。我们应用了基于先验和数据驱动的策略来分析 46 名 ASD 儿童、46 名 ADHD 儿童和 36 名 TDC（年龄 7-11.9 岁）的 RT 表现。具体而言，我们根据四个预先选定的频带的振幅以及 0.006 到 0.345 Hz 之间的 400 个频带来对比组间差异。在二次分析中，我们将 ASD 组分为有大量 ADHD 症状的儿童（ASD(+)）和无大量 ADHD 症状的儿童（ASD(-)）。无论采用哪种策略，ADHD 儿童的 RT-ISV 波动频率在 0.20 到 0.345 Hz 之间，而 ASD 儿童的 RT-ISV 波动频率则无法将其与 TDC 区分开来。ASD(+)和 ADHD 儿童的 RT-ISV 波动幅度在 0.18 到 0.345 Hz 之间高于 TDC。相比之下，ASD(-)亚组的 RT-ISV 频率波动与 TDC 无差异。频率在 0.18-0.345 Hz 之间的 RT-ISV 波动（即 3 到 5 秒之间的时间段）与 ADHD 症状相关，无论分类诊断如何，都可能是一种生物标志物。这些结果表明，ADHD 儿童和 ASD(+)儿童的 RT-ISV 具有共同的潜在病理生理机制。
