Department of Neuropsychology , Kennedy Krieger Institute , Baltimore , MD , USA.
Child Neuropsychol. 2011;17(3):209-24. doi: 10.1080/09297049.2010.532204.
Processing-speed deficits affect reading efficiency, even among individuals who recognize and decode words accurately. Children with ADHD who decode words accurately can still have inefficient reading fluency, leading to a bottleneck in other cognitive processes. This "slowing" in ADHD is associated with deficits in fundamental components of executive function underlying processing speed, including response selection. The purpose of the present study was to deconstruct processing speed in order to determine which components of executive control best explain the "processing" speed deficits related to reading fluency in ADHD. Participants (41 ADHD, 21 controls), ages 9-14 years, screened for language disorders, word reading deficits, and psychiatric disorders, were administered measures of copying speed, processing speed, reading fluency, working memory, reaction time, inhibition, and auditory attention span. Compared to controls, children with ADHD showed reduced oral and silent reading fluency and reduced processing speed-driven primarily by deficits on WISC-IV Coding. In contrast, groups did not differ on copying speed. After controlling for copying speed, sex, severity of ADHD-related symptomatology, and GAI, slowed "processing" speed (i.e., Coding) was significantly associated with verbal span and measures of working memory but not with measures of response control/inhibition, lexical retrieval speed, reaction time, or intrasubject variability. Further, "processing" speed (i.e., Coding, residualized for copying speed) and working memory were significant predictors of oral reading fluency. Abnormalities in working memory and response selection (which are frontally mediated and enter into the output side of processing speed) may play an important role in deficits in reading fluency in ADHD, potentially more than posteriorally mediated problems with orienting of attention or perceiving the stimulus.
加工速度缺陷会影响阅读效率，即使是那些准确识别和解码单词的个体也是如此。准确解码单词的 ADHD 儿童仍然可能存在阅读流畅性效率低下的问题，从而导致其他认知过程出现瓶颈。ADHD 中的这种“减速”与执行功能基本成分（包括反应选择）的加工速度缺陷有关。本研究的目的是对加工速度进行解构，以确定执行控制的哪些成分能最好地解释与 ADHD 阅读流畅性相关的“加工”速度缺陷。参与者（41 名 ADHD 儿童和 21 名对照组儿童）年龄在 9-14 岁之间，经过语言障碍、单词阅读障碍和精神障碍筛查，接受了复制速度、加工速度、阅读流畅性、工作记忆、反应时间、抑制和听觉注意力跨度的测试。与对照组相比，ADHD 儿童的口头和默读流畅性较低，加工速度较慢，主要原因是 WISC-IV 编码测试中的缺陷。相比之下，两组在复制速度上没有差异。在控制了复制速度、性别、ADHD 相关症状的严重程度和 GAI 后，较慢的“加工”速度（即 WISC-IV 编码）与言语广度和工作记忆测量显著相关，但与反应控制/抑制、词汇检索速度、反应时间或个体内变异性无关。此外，“加工”速度（即 WISC-IV 编码，按复制速度残差化）和工作记忆是口头阅读流畅性的显著预测因素。工作记忆和反应选择（它们是由额叶介导并进入加工速度的输出端）的异常可能在 ADHD 阅读流畅性缺陷中起着重要作用，这可能比注意定向或感知刺激的后部介导问题更为重要。
