Department of Pediatrics, Cincinnati Children's Hospital Medical Center.
Neuropsychology. 2011 Jul;25(4):427-441. doi: 10.1037/a0022155.
The purpose of the research study was to examine the manifestation of variability in reaction times (RT) in children with attention deficit hyperactivity disorder (ADHD) and to examine whether RT variability presented differently across a variety of neuropsychological tasks, was present across the two most common ADHD subtypes, and whether it was affected by reward and event rate (ER) manipulations.
Children with ADHD-combined type (n = 51), ADHD-predominantly inattentive type (n = 53), and 47 controls completed five neuropsychological tasks (Choice Discrimination Task, Child Attentional Network Task, Go/No-Go task, Stop Signal Task, and N-back task), each allowing trial-by-trial assessment of RTs. Multiple indicators of RT variability including RT standard deviation, coefficient of variation and ex-Gaussian tau were used.
Children with ADHD demonstrated greater RT variability than controls across all five tasks as measured by the ex-Gaussian indicator tau. There were minimal differences in RT variability across the ADHD subtypes. Children with ADHD also had poorer task accuracy than controls across all tasks except the Choice Discrimination task. Although ER and reward manipulations did affect children's RT variability and task accuracy, these manipulations largely did not differentially affect children with ADHD compared to controls. RT variability and task accuracy were highly correlated across tasks. Removing variance attributable to RT variability from task accuracy did not appreciably affect between-groups differences in task accuracy.
High RT variability is a ubiquitous and robust phenomenon in children with ADHD.
本研究旨在考察注意缺陷多动障碍（ADHD）儿童反应时（RT）变异性的表现，并考察 RT 变异性是否在各种神经心理学任务中表现不同，是否存在于两种最常见的 ADHD 亚型中，以及是否受到奖励和事件率（ER）操纵的影响。
共 51 名 ADHD 混合型儿童、53 名 ADHD 注意力不集中型儿童和 47 名对照组儿童完成了 5 项神经心理学任务（选择辨别任务、儿童注意网络任务、Go/No-Go 任务、停止信号任务和 N-back 任务），每项任务都允许对 RT 进行逐次评估。使用了多种 RT 变异性指标，包括 RT 标准差、变异系数和外伽马 tau。
与对照组相比，ADHD 儿童在所有五项任务中均表现出更大的 RT 变异性，外伽马 tau 指标显示。在 ADHD 亚型之间，RT 变异性差异极小。除了选择辨别任务外，ADHD 儿童在所有任务中的任务准确性均低于对照组。虽然 ER 和奖励操纵确实影响了儿童的 RT 变异性和任务准确性，但这些操纵在很大程度上并没有使 ADHD 儿童与对照组产生差异。RT 变异性和任务准确性在任务之间高度相关。从任务准确性中去除归因于 RT 变异性的方差并没有显著影响任务准确性的组间差异。
高 RT 变异性是 ADHD 儿童普遍存在且稳健的现象。
