7-11岁正常儿童和ADHD儿童故事重述能力及策略的发展

儿童的故事重述涉及工作记忆和抽象表征能力，是与儿童的日常学业任务密切联系。儿童能否把握时间线索来组织故事重述，反映的是儿童抽象出故事事件内在时间关系的能力，因此对儿童故事重述的探查可以揭示儿童抽象思维发展的一般规律和特点。本研究在前人研究的基础上，系统探查了7－11岁儿童故事重述能力及其策略的发展过程，探讨了时间线索对儿童故事重述的影响，并对ADHD儿童和正常儿童的故事重述及策略进行了比较。 主要研究结果如下： (1)7－11岁儿童故事重述能力总体上随年龄增长而提高，按正确顺序重述的事件数量增多，重述过程中提取和使用的时间线索也增加。其中7－9岁有较快速的发展。 (2)随故事中包含的事件数量的增加，故事难度增大，儿童的故事重述成绩有所下降，故事长度对7岁和9岁儿童的影响大于对11岁儿童的影响。 (3)有、无时间线索语词会影响儿童的故事重述。故事中包含时间语词线索有助于儿童的故事重述。11岁儿童的故事重述已不受有、无时间线索的影响，他们在无时间线索的条件下，更多地主动使用表示因果关系的语词来表征事件关系。 (4)ADHD儿童的故事重述能力在9岁到11岁有较快的发展。但总体而言，ADHD儿童对含有时间线索故事的重述能力显著差于正常儿童。 (5)故事再学习对ADHD儿童和正常儿童的故事重述都存在促进作用。但ADHD儿童故事再学习效果不如正常儿童，低龄儿童中差距尤其明显，随着年龄的增加，ADHD儿童与正常儿童故事再学习效果的差距逐渐缩小。 (6)不同年龄的儿童主要采用四种策略解决问题。随年龄增长，正常儿童和ADHD儿童中使用水平较高的内容主线和逻辑关系策略的人数都有所增加。但ADHD儿童中高水平策略使用人数比例仍低于正常儿童。

Attention deficit/hyperactivity disorder children with a 7-repeat allele of the dopamine receptor D4 gene have extreme behavior but normal performance on critical neuropsychological tests of attention

An association of the dopamine receptor D4 (DRD4) gene located on chromosome 11p15.5 and attention deficit/hyperactivity disorder (ADHD) has been demonstrated and replicated by multiple investigators. A specific allele [the 7-repeat of a 48-bp variable number of tandem repeats (VNTR) in exon 3] has been proposed as an etiological factor in attentional deficits manifested in some children diagnosed with this disorder. In the current study, we evaluated ADHD subgroups defined by the presence or absence of the 7-repeat allele of the DRD4 gene, using neuropsychological tests with reaction time measures designed to probe attentional networks with neuroanatomical foci in D4-rich brain regions. Despite the same severity of symptoms on parent and teacher ratings for the ADHD subgroups, the average reaction times of the 7-present subgroup showed normal speed and variability of response whereas the average reaction times of the 7-absent subgroup showed the expected abnormalities (slow and variable responses). This was opposite the primary prediction of the study. The 7-present subgroup seemed to be free of some of the neuropsychological abnormalities thought to characterize ADHD.