成人注意缺陷多动障碍患者工作记忆特点的事件相关电位研究

An event-related potential study of working memory in adults with attention-deficit/hyperactivity disorder

目的探讨成人注意缺陷多动障碍(attention-deficit/hyperactivity disorder,ADHD)患者的工作记忆事件相关电位特点。方法选取门诊和随诊治疗的成人ADHD患者43例(ADHD组)及与其性别、年龄和智商相匹配的健康对照者40名(对照组)进行言语n-back任务并记录任务下脑电数据,采用重复测量方差分析比较2组随记忆负荷的增加反应时间、正确率、个体内反应时标准差(intra-individual standard deviation of response time,ISD)和P300成分波幅和潜伏期等组内和组间的差异;采用Pearson相关分析分析行为学和电生理指标与临床症状的相关性。结果ADHD组完成1-back任务[(505±100)ms与(457±75)ms,F(1,81)=5.94,P=0.017]和2-back任务[(573±125)ms与(511±100)ms,F(1,81)=6.05,P=0.016]反应时间均长于对照组。ADHD组完成n-back任务ISD明显较对照组大,存在组别主效应[F(1,81)=6.03,P=0.016]。ADHD组完成2-back任务时P300波幅较对照组显著减小[F(1,78)=4.14,P=0.045]。相关分析显示:ADHD患者多动冲动症状越严重,完成2-back任务反应时间越长(r=0.303,P=0.48)。ADHD患者多动冲动症状越严重,完成n-back任务时P300波幅越低。ADHD患者注意缺陷症状越严重,完成n-back任务时P300潜伏期越长。结论成人ADHD患者完成n-back任务时反应时间延长且ISD增大、P300波幅减低,与临床症状相关,提示患者信息加工速度慢、注意波动性大、工作记忆再提取过程受损。

Objective To evaluate the working memory(WM)performance of adults with attention-deficit/hyperactivity disorder(ADHD)using event-related potential(ERP),and to examine whether there is output dysfunction of their WM resource under increasing memory load.Method Forty-three adult ADHD patients,and 40 healthy controls matched in gender ratio,age and IQ were recruited to participate in the study.All participants were required to perform a verbal n-back test with EEG recording.Behavioral indices including reaction time(RT),intra-individual reaction time variability(ISD)and accuracy rate were recorded by software E-prime.Meanwhile,electrophysiology indexes were recorded by EEG/ERP recording system EGI.Comparisons were conducted between ADHD patients and normal controls on their behavioral performances of RT,accuracy rate and ISD and their electrophysiology component of P300.Pearson correlation analysis was used to compare the correlation between behavioral,electrophysiological indicators and clinical symptoms.Results Behaviorally,ADHD patients performed with a longer RT than healthy controls under 1-back((505±100)ms vs.(457±75)ms,F(1,81)=5.94,P=0.017)and 2-back((573±125)ms vs.(511±100)ms,F(1,81)=6.05,P=0.016).Main effect of group on ISD was found(F(1,81)=6.03,P=0.016),where adult ADHD patients performed significantly higher than healthy controls.Neurophysiolocally,significantly lower amplitude of P300 component under 2-back task was found among ADHD patients compared to healthy controls(F(1,78)=4.14,P=0.045).Correlation analysis:the more severe the hyperactivity symptoms of adult ADHD,the longer reaction time to complete the 2-back task(r=0.303,P=0.48).The more severe the hyperactivity symptoms of adult ADHD,the lower P300 amplitude to complete the n-back task.The more severe the attention deficit symptom of adult ADHD,the longer P300 latency to complete the n-back task.Conclusions Adult ADHD patients may have prolonged response time,increased variability and decreased P300 amplitude compared to the control subjects in n-back task,which is correlated to clinical symptoms.These signs suggest the impairment in retrieval of working memory,and an unstable attention,as well as slower information processing speed among adult patients with ADHD.