Contextual abnormalities of saccadic inhibition in children with attention deficit hyperactivity disorder
Contextual abnormalities of saccadic inhibition in children with attention deficit hyperactivity disorder
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DOI：
10.1007/s002210100890
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发表时间：
2001-12-01
影响因子：
2
通讯作者：
Currie, J
中科院分区：
文献类型：
--
作者：
Cairney, S;Maruff, P;Currie, J
注意力缺陷多动障碍（ADHD）儿童的执行功能障碍是一致的，据推测，这些出现是因为行为抑制系统的破坏。比较了未服药和服药的ADHD儿童（混合型）、年龄匹配的健康儿童和健康成人的执行和抑制功能。执行功能是使用空间工作记忆测试来测量的，该测试先前显示出对ADHD和兴奋剂药物敏感。抑制功能的测量使用眼运动范式，需要个人使用任务上下文来控制固定的释放。根据目标出现在两个位置中的任何一个的概率来设置上下文。在一个区块中，目标出现在80%的试验中。在另一个区块中，目标出现在20%的试验中。控制注视释放的能力是从注视偏移效应（FOE）推断的，或者当当前注视在扫视目标开始之前偏移200 ms（间隙条件）时与没有偏移时（重叠条件）相比扫视潜伏期的差异。虽然健康儿童在空间工作记忆任务上的错误比健康成人多，但两组在利用上下文控制注视的能力上没有差异。当目标概率较低时，两者都显示出较大的FOE。正如预期的那样，未服药的ADHD组在空间工作记忆测试中比健康儿童犯了更多的错误，尽管在服药的ADHD组中空间工作记忆表现正常。然而，未用药和用药ADHD组都无法根据上下文调节FOE，这是由于当目标概率较低时，他们无法自愿抑制扫视。这些数据表明，基于上下文的调节的固定释放是不控制的相同的系统，控制执行功能。此外，在ADHD儿童中，执行功能和抑制控制的缺陷似乎是独立的。
Abnormalities of executive function are observed consistently in children with attention-deficit hyperactivity disorder (ADHD), and it is hypothesised that these arise because of disruption to a behavioural inhibition system. Executive and inhibitory functions were compared between unmedicated and medicated children with ADHD (combined type), age-matched healthy children and healthy adults. Executive functions were measured using a test of spatial working memory shown previously to be sensitive to ADHD and to stimulant medication. Inhibitory functions were measured using an ocular motor paradigm that required individuals to use task context to control the release of fixation. Context was set according to the probability that a target would appear at either of the two locations. In one block, targets appeared on 80% of trials. In the other block, targets appeared on 20% of trials. The ability to control the release of fixation was inferred from the fixation offset effect (FOE), or the difference in saccade latency when the current fixation is offset 200 ms prior to the onset of the saccade target (gap condition), compared with when there is no offset (overlap condition). Although the healthy children made more errors on the spatial working memory task than the healthy adults, there was no difference between the two groups in their ability to control fixation using context. Both showed a larger FOE when target probability was low. As expected, the unmedicated ADHD group made more errors on the spatial working memory test than the healthy children, although spatial working memory performance was normal in the medicated ADHD group. However, both the unmedicated and medicated ADHD groups were unable to modulate the FOE according to context, and this was due to their inability to voluntarily inhibit saccades when there was a low target probability. These data suggest that the context-based modulation of fixation release is not controlled by the same systems that control executive function. Furthermore, deficits in executive function and inhibitory control appear independent in children with ADHD.