Teicher Martin H, Lowen Steven B, Polcari Ann, Foley Mary, McGreenery Cynthia E
Department of Psychiatry, Harvard Medical School, Boston, MA, USA.
J Child Adolesc Psychopharmacol. 2004 Summer;14(2):219-32. doi: 10.1089/1044546041648995.
Continuous performance tasks (CPTs) provide a method for studying some components of attention, but do not take into account that attention fluctuates from moment to moment. To address this issue, CPT performance was classified into one of four states (on-task, impulsive, distracted, or randomly responding) every 30 seconds, based on commission and omission error rates. We evaluated this method on 60 boys (10.6 +/- 1.1 years) with attention-deficit hyperactivity disorder (ADHD)-Combined subtype, tested before and after a dose of methylphenidate (MPH, 0.4 mg/kg), and 8 unmedicated healthy control boys (11.3 +/- 2.0 years of age). Healthy controls were on-task during 82.4% of the 30-second epochs, and made an average of 5.4 attention shifts. In contrast, children with ADHD were only on-task during 42.6% of the epochs (p = 0.0006), and they made an average of 12.8 attention shifts (p = 0.00004). These state measures provided more robust indicators of the difference between children with ADHD and controls than did traditional CPT measures of error rates, latency, and variability. The new state measures were also more significantly affected by MPH. MPH produced a 77% increase in the percent of time children with ADHD spent on-task (p < 10(12)). Conversely, MPH reduced time spent in the distracted, impulsive, and random response states by 79%, 44.5%, and 69.2%, respectively (all p values < 0.0002). Unlike errors of omission and commission, which are highly correlated (r = 0.722, n = 60, p < 10(-11)), the percent of epochs spent in impulsive, distracted, and random response states were uncorrelated, and loaded onto discrete independent factors on principal component analysis. The level of activity during the CPT correlated with the degree of distraction, but not with the degree of impulsivity. Children with ADHD could be subtyped according to the nature of their attention performance problems, and these subtypes differed in levels of hyperactivity and degrees of response to MPH.
连续执行任务（CPT）为研究注意力的某些组成部分提供了一种方法，但未考虑到注意力会时刻波动。为解决这一问题，基于错误率和遗漏错误率，每30秒将CPT表现分类为四种状态之一（专注任务、冲动、分心或随机反应）。我们在60名患有注意力缺陷多动障碍（ADHD）合并型亚型的男孩（10.6±1.1岁）身上评估了这种方法，这些男孩在服用一剂哌甲酯（MPH，0.4mg/kg）之前和之后接受了测试，还有8名未用药的健康对照男孩（11.3±2.0岁）。健康对照在30秒时间段的82.4%内专注于任务，平均进行5.4次注意力转移。相比之下，患有ADHD的儿童在这些时间段内只有42.6%的时间专注于任务（p = 0.0006），他们平均进行12.8次注意力转移（p = 0.00004）。与传统的CPT错误率、潜伏期和变异性测量相比，这些状态测量为患有ADHD的儿童与对照组之间的差异提供了更有力的指标。新的状态测量也更显著地受到MPH的影响。MPH使患有ADHD的儿童专注于任务的时间百分比增加了77%（p < 10⁻¹²）。相反，MPH分别将在分心、冲动和随机反应状态下花费的时间减少了79%、44.5%和69.2%（所有p值< 0.0002）。与高度相关的遗漏错误和执行错误不同（r = 0.722，n = 60，p < 10⁻¹¹），在冲动、分心和随机反应状态下花费的时间段百分比不相关，并且在主成分分析中加载到离散的独立因素上。CPT期间的活动水平与分心程度相关，但与冲动程度无关。患有ADHD的儿童可以根据其注意力表现问题的性质进行亚型分类，并且这些亚型在多动水平和对MPH的反应程度上有所不同。
