Spencer Sarah V, Hawk Larry W, Richards Jerry B, Shiels Keri, Pelham William E, Waxmonsky James G
Department of Psychology, University at Buffalo, SUNY, Park Hall, Box 604110, Buffalo, NY 14260-4110, USA.
J Abnorm Child Psychol. 2009 Aug;37(6):805-16. doi: 10.1007/s10802-009-9316-2.
Recent research has suggested that intra-individual variability in reaction time (RT) distributions of children with ADHD is characterized by a particularly large rightward skew that may reflect lapses in attention. The purpose of the study was to provide the first randomized, placebo-controlled test of the effects of the stimulant methylphenidate (MPH) on this tail and other RT distribution characteristics. Participants were 49 9- to 12-year-old children with ADHD. Children participated in a 3-day double-blind, placebo-controlled medication assessment during which they received long-acting MPH (Concerta), with the nearest equivalents of 0.3 and 0.6 mg/kg t.i.d. immediate-release MPH. Children completed a simple two-choice speeded discrimination task on and off of medication. Mode RT and deviation from the mode were used to examine the peak and skew, respectively, of RT distributions. MPH significantly reduced the peak and skew of RT distributions. Importantly, the two medication effects were uncorrelated suggesting that MPH works to improve both the speed and variability in responding. The improvement in variability with stimulant treatment is interpreted as a reduction in lapses in attention. This, in turn, may reflect stimulant enhancement of self-regulatory processes theorized to be at the core of ADHD.
近期研究表明，注意力缺陷多动障碍（ADHD）儿童反应时间（RT）分布的个体内变异性具有特别大的右偏态特征，这可能反映了注意力的 lapses。本研究的目的是首次对兴奋剂哌甲酯（MPH）对该尾部及其他RT分布特征的影响进行随机、安慰剂对照试验。参与者为49名9至12岁的ADHD儿童。儿童参加了为期3天的双盲、安慰剂对照药物评估，在此期间他们接受了长效MPH（康奈达），其等效剂量分别为0.3和0.6毫克/千克每日三次速释MPH。儿童在服药和不服药时完成了一项简单的二选一快速辨别任务。RT分布的众数和与众数的偏差分别用于检验RT分布的峰值和偏态。MPH显著降低了RT分布的峰值和偏态。重要的是，这两种药物效应不相关，表明MPH有助于提高反应速度和变异性。兴奋剂治疗导致的变异性改善被解释为注意力 lapses 的减少。反过来，这可能反映了兴奋剂对理论上处于ADHD核心的自我调节过程的增强作用。
