注意缺陷多动障碍儿童选择性注意受损的脑影像学特征

Brain imaging characteristics of selective attention deficits in children with ADHD

目的:探究注意缺陷多动障碍(ADHD)患者选择性注意能力受损及与任务相关的大脑激活特点。方法:选取24例符合精神障碍诊断与统计手册第4版(DSM-IV)诊断的ADHD儿童和26例年龄匹配的正常对照儿童,使用视觉搜索范式,在两种任务难度条件下,通过任务态功能磁共振成像实验比较其与选择性注意有关的任务表现和大脑激活情况。结果:与正常对照相比,ADHD儿童在视觉搜索任务中正确率降低[(78.81±12.95)%vs.(86.90±10.06)%,P<0.01],左侧额下回的神经活动减弱[(0.10±0.22)%vs.(0.25±0.22)%,P<0.05],且两组被试在完成视觉搜索任务时,左侧额下回的神经活动强度与任务正确率呈正相关(r=0.28,P<0.05)。结论:ADHD儿童选择性注意能力受损,左侧额下回活动减弱可能参与其选择性注意能力缺陷的神经病理机制。

Objective:To explore the deficits of selective attention in children with attention-deficit/hyperactivity disorder(ADHD)and the related neural substrates.Methods:Twenty-four children diagnosed as ADHD according to the Diagnostic and Statistical Manual of Mental Disorders,Fourth Edition(DSM-Ⅳ)and 26 agematched normal controls were recruited.Participants finished visual search tasks under two task difficulty conditions in the task functional magnetic resonance imaging(fMRI)experiment.Task performance and brain activation related to selective attention were compared between groups.Results:Children with ADHD had worse accuracy[(78.81±12.95)%vs.(86.90±10.06)%,P<0.01]and decreased activation in the left inferior frontal gyrus(IFG)[(0.10±0.22)%vs.(0.25±0.22)%,P<0.05]than the normal controls in both tasks.Moreover,the intensity of the left IFG activation was significantly positively correlated with task accuracy(r=0.28,P<0.05).Conclusion:These findings suggest that dysfunctions in the left IFG in children with ADHD might be involved in the neuropathological mechanism of their selective attention deficits.