有冲动行为注意缺陷多动障碍儿童脑功能性磁共振的研究

A functional MRI study in ADHD children with impulsivity

目的冲动是注意缺陷多动障碍(ADHD)儿童的核心症状。为了解ADHD患儿冲动行为的神经机制,该研究利用功能性磁共振成像技术调查了有冲动行为ADHD儿童的脑功能影像特点。方法以GO/STOP冲动行为测量软件中的GO及STOP为任务,对自愿参加的10例有冲动行为ADHD、7例无冲动行为ADHD及9例正常男童进行脑功能成像。然后将3组儿童的脑功能像分别合并平均,得出3组在执行两个任务时的平均脑功能像,最后比较3组平均脑激活区的分布情况。结果执行GO任务时,正常儿童的激活区域主要是额极(额上回、额中回、额内侧回);无冲动ADHD患儿是小脑(后叶、前叶小结)、扣带回;冲动ADHD患儿是内侧苍白球、岛叶。执行STOP任务时,正常儿童的激活区域主要为额上回等区域;无冲动ADHD患儿为额中回、胼胝体;冲动ADHD患儿为钩回、扣带回。冲动ADHD儿童的激活的脑区远较其他两组少。结论参与控制冲动的大脑皮层分布广泛,与正常儿童相比,无冲动行为ADHD患儿脑功能明显不足,激活的脑区少;有冲动行为ADHD患儿激活的脑区更少,脑功能表现更差,皮层唤醒不足。

Objective hnpulsivity is one of the core symptoms of children with attention deficit hyperactivity disorder （ADHD）. In order to understand the neuromechanism of the impulsive behaviors in ADHD children, this study investigated the specific functional areas of the brain by functional MRI. Methods The subjects consisted of 10 ADHD children with impulsivity, 7 ADHD children without impulsivity and 9 normal children. A functional MR/examination was performed when the subjects were instructed to finish GO and STOP tasks with the GO-STOP impulsivity paradigm. The MRI data during the two tasks of GO and STOP were averaged and the corresponding activation regions between groups were compared. Results The data from the GO task revealed that the main activation regions of the normal children included frontal pole （superior frontal gyrus, middle frohtal gyrus and medial frontal gyrus） ; the main activation regions of ADHD children without impulsivity were cerebellum （posterior lobe and anterior lobe bouton ） and cingulated gyrus; those of ADHD children with impulsivity were medial globus pallidus and insula. The data from the STOP task showed that the main activation regions of normal children included superior frontal gyrus and middle frontal gyrus; those of ADHD children without impulsivity were middle frontal gyrus and cingulate gyrus ; those of ADHD children with impulsivity were uncus and putamen. The activation regions of ADHD children with impulsivity were much fewer than the other two groups. Conclusions The behavior of impulsivity-control involves a number of specific functional areas in the cerebral cortex. Compared with normal children, ADHD children without impulsivity have weaker brain function and brain activation, and ADHD children with impulsivity demonstrate much fewer brain activation regions, worse brain function and little awareness of the cerebral cortex.