注意缺陷多动障碍患儿工作记忆功能的近红外光谱成像研究

Working memory assessed by functional near-infrared spectroscopy in child patients with attention deficit hyperactivity disorder

目的 初步探讨注意缺陷多动障碍（attention deficit hyperactivity disorder,ADHD）患儿执行工作记忆任务过程中前额叶皮质的激活特点.方法 选用n-back范式为工作记忆功能的心理学任务,应用功能性近红外光谱成像技术（functional near-infrared spectroscopy,fNIRS）检测12例ADHD患儿（ADHD组）和年龄、性别相匹配的13例健康儿童（对照组）在执行n-back任务时前额叶皮质氧合血红蛋白浓度的变化,同步记录行为学数据（按键正确的次数）.采用t检验对2组氧合血红蛋白浓度变化平均值和按键正确的次数进行比较.结果（1）0-back任务和1-back任务期间ADHD组较对照组按键正确次数低（0-back：t=-2.222,P=0.043;1-back：t=-3.276,P=0.005）.（2）0-back任务期间,对照组和ADHD组全部52个通道氧合血红蛋白浓度变化差异无统计学意义;在1-back任务期间,ADHD组[（0.022±0.040）mmol/（L·mm）]第18通道的氧合血红蛋白浓度变化弱于对照组[（0.085±0.040） mmol/（L·mm）;t=3.88,P〈0.05].结论 ADHD患儿在执行工作记忆任务过程中左侧背外侧前额叶激活减弱.

Objective To study the activation characteristics in the prefrontal cortex（PFC） of children with attention deficit hyperactivity disorder （ADHD） in the working memory tasks by using functional near-infrared spectroscopy（fNIRS）. Methods In this study, 12 children with ADHD and 13 typically developing children were studied. N-back task was chosen as the neuropsychology task. The functional blood oxygen metabolism signals and the correct number of key-press were recorded when the children performed n-back task by using fNIRS. The average change of the hemoglobin concentration and the correct number of keys were compared by t test.Results （1）In the behavior data,ADHD children had a lower correct number of key-press compared with typically developing children at both 0-back and 1-back task conditions（0-back：t=-2.222,P=0.043;1-back：t=-3.276,P=0.005）.（2）For the 0-back task condition, there was no statistical difference between the two groups. For the 1-back task condition, task-related increment of the oxygen-Hb concentration, the marker of cortex activation, in ADHD children was significantly smaller than the typically developing children for channel 18, which was located in left dorsolateral prefrontal cortex（DLPFC）（ADHD children：（0.022±0.040）mmol/（L·mm）;Typical Developing Children：（0.085 ± 0.040）mmol/（L·mm）; t=3.88,P〈0.05）. Conclusions The PFC activation in ADHD children may be significantly decreased, which probably indicates a working memory defect in ADHD children.