激活水平对两亚型ADHD儿童反应执行与抑制能力的影响

研究选取了混合型ADHD儿童14名,注意缺陷型ADHD儿童16名以及正常儿童18名,考察了在不同激活水平下,两亚型ADHD儿童之间,及其与正常儿童之间的反应执行能力与抑制能力的异同。采用传统的go/no-go任务,并将刺激间的时间间隔设置为1秒、4秒、8秒三种条件,分别对应高、中、低三种激活水平。结果发现,(1)与正常儿童相比,ADHD儿童的反应执行能力更容易受到激活水平的影响,且两亚型ADHD儿童受到的影响模式基本一致。具体而言:在高激活水平下,ADHD儿童与正常儿童差异最小;在中、低激活水平下,ADHD儿童与正常儿童差异增大,表明ADHD儿童状态调节能力落后。(2)两亚型ADHD儿童的功能缺损模式不同,混合型儿童在状态调节和反应抑制两方面都存在缺损,且其反应抑制缺陷不受激活水平影响;注意缺陷型儿童仅在状态调节方面受损。     

两亚型注意缺陷多动障碍(ADHD)儿童的内隐注意定向

研究探讨注意缺陷障碍儿童与正常儿童之间,混合型与注意缺陷型ADHD儿童之间在内源与外源注意定向功能的差异。ADHD儿童及与之匹配的正常儿童对照组分别参与了两个实验,实验一采用了内源性内隐注意定向任务,实验二采用了外源性内隐注意定向任务。研究表明：（1）ADHD儿童与正常儿童相比,在注意定向过程（注意解除、转移与施加）上有一定缺陷。（2）ADHD儿童注意定向网络功能有缺陷,与反应水平上动作准备有关的注意功能可能受损。（3）两种亚类型儿童注意定向功能缺陷模式不同。在内原定向上,混合型与注意缺陷型相比较,混合型ADHD儿童表现为有较强的反应冲动性;注意缺陷型儿童,主要表现为注意加工过程比较缓慢,注意更易涣散。在外源定向上,混合型儿童在反应的运动准备及运动控制方面的缺陷要大于注意缺陷型儿童     

注意缺陷多动障碍儿童在不同加工阶段的干扰控制

采用刺激－刺激和刺激－反应相容性任务范式,将信息加工在知觉和反应阶段的冲突效应分离开来,考察注意缺陷多动障碍（Attention Deficit Hyperactivity Disorder,简称ADHD）儿童在知觉和反应阶段冲突控制的模式和时间轨迹。结果发现,在反应阶段,ADHD儿童的干扰控制能力明显弱于正常对照组儿童,混合型ADHD儿童的能力更弱于注意缺陷型ADHD儿童;在知觉阶段,ADHD儿童没有明显的干扰抑制缺损,两组ADHD儿童（注意缺陷型和混合型）的表现模式相似;儿童抑制冲突干扰所遵循的时间轨迹在知觉和反应阶段有所不同：与知觉阶段相比,反应阶段需要更长的时间才能抑制冲突干扰。但ADHD儿童和正常儿童之间的表现模式相似     

两种亚型ADHD儿童的促进和抑制加工

采用图片Stroop任务,对两种亚型ADHD儿童的促进和抑制加工进行了研究。结果发现,不论在反应时还是错误率上,ADHD儿童和正常儿童在促进效应上的表现模式相似,但ADHD儿童在错误率上比正常儿童表现出更大的抑制效应,混合型ADHD儿童的抑制效应更大于注意缺陷型儿童。由于ADHD儿童仅选择性地在抑制加工上受损,而促进加工正常,这一结果提示,促进和抑制可能是具有不同机制的、分离的加工过程。     

ADHD儿童的选择性抑制

采用较传统停止信号任务更为精确的选择性停止信号任务,探索ADHD的选择性抑制缺陷的机制。结果发现,ADHD儿童在选择性停止信号任务上,抑制失败的比率明显高于正常儿童,但是其执行加工速度和抑制加工速度与正常儿童没有差异,另外,ADHD儿童表现出了更大的反应变异性。研究认为,ADHD在选择性停止信号任务上的抑制缺陷并非由于抑制加工速度过慢所导致,而是由于其不能很好地维持最佳的激活状态所导致,状态调节理论更能反映ADHD的本质。     

视觉选择性注意对注意缺损多动障碍儿童数字距离效应的影响

采用Posner的内源性和外源性线索实验范式,材料为1~9的阿拉伯数字(不包括5),以判断目标数字是否大于5为任务,考察视觉选择性注意中的内源性注意和外源性注意对注意缺陷型多动障碍儿童(ADHD)数字加工距离效应的影响。结果发现:(1)内源性和外源性注意条件下,正常儿童在数字判断加工任务中的反应时短于ADHD儿童;(2)内源性有效线索提示条件下,ADHD儿童和正常儿童均表现出显著的数字距离效应;而无效线索提示条件下,ADHD儿童的大小数字距离效应均不明显,正常儿童仍然表现出显著的数字距离效应;(3)外源性有效线索提示条件下,ADHD儿童的小数字距离效应显著,但大数字距离效应不明显,正常儿童则表现出显著的大小数字距离效应;而无效线索提示条件下,只有正常儿童表现出显著的数字距离效应,ADHD儿童的数字距离效应不显著。     

奖惩对注意缺陷多动障儿童情感决策的影响

采用简化版儿童赌博任务,其中操纵了奖励和惩罚的强度,探察两种亚型(注意缺陷型和混合型)ADHD儿童的情感决策能力,同时采集儿童在任务中的皮肤电活动以探析ADHD儿童在情感决策中的生理机制.结果发现,在不同的奖惩强度下,ADHD儿童情感决策模式不同,在即刻奖励条件下,ADHD儿童情感决策的能力明显弱于正常对照组儿童,倾向于不利选择,所产生的预测性皮电振幅也明显低于正常对照组;在即刻惩罚条件下,ADHD儿童的情感决策能力未见异常.两种亚型ADHD儿童的表现模式相似.上述结果证明,ADHD儿童仅存在对奖励的异常敏感性,并确实影响了其决策能力,而其回避惩罚的能力正常.两种亚型ADHD儿童存在的问题相似.     

奖惩对注意缺陷多动障碍儿童情感决策的影响

采用简化版儿童赌博任务,其中操纵了奖励和惩罚的强度,探察两种亚型（注意缺陷型和混合型）ADHD儿童的情感决策能力,同时采集儿童在任务中的皮肤电活动以探析ADHD儿童在情感决策中的生理机制。结果发现,在不同的奖惩强度下,ADHD儿童情感决策模式不同,在即刻奖励条件下,ADHD儿童情感决策的能力明显弱于正常对照组儿童,倾向于不利选择,所产生的预测性皮电振幅也明显低于正常对照组;在即刻惩罚条件下,ADHD儿童的情感决策能力未见异常。两种亚型ADHD儿童的表现模式相似。上述结果证明,ADHD儿童仅存在对奖励的异常敏感性,并确实影响了其决策能力,而其回避惩罚的能力正常。两种亚型ADHD儿童存在的问题相似     

不同亚型ADHD儿童的视通道时距估计能力

本研究选取ADHD混合型儿童11名,ADHD注意缺损型儿童13名以及正常儿童15名,通过"平均估计长度"、"平均估计误差百分比"、"估计变异值"三个指标,考察不同亚型ADHD儿童在时距复制和言语估计上的稳定性和精确性。研究发现,在视觉刺激条件下,ADHD儿童的时距估计缺损并不受时距长度的影响;ADHD混合型儿童在多项任务中所表现的稳定性和精确性都差,而ADHD缺损型儿童只是稳定性差,说明ADHD混合型是ADHD中更严重的亚类型;ADHD儿童在时距估计任务中稳定性差,反映了其状态调节能力的落后。     

儿童注意缺陷多动障碍(ADHD)的“冷”“热”执行功能

近30多年来,对注意缺陷多动障碍(ADHD)的认知缺损机制的关注一直停留在"冷"执行功能领域,为更全面地揭示其执行缺损机制,文章旨在从"冷""热"执行功能的角度来探讨ADHD的缺陷。论文简要回顾了注意缺陷多动障碍的界定、生理基础和若干理论模型,着重阐述ADHD儿童在经典"冷""热"两类执行功能任务上的表现差异。总结认为ADHD儿童并非在所有类型的"热"执行任务上表现落后,ADHD儿童的表现要视情感和动机的卷入对不同任务情景的作用性质是消极还是积极而定,文章也比较分析了几位研究者相关的理论解释。     

Response Style Differences in the Inattentive and Combined Subtypes of Attention-Deficit/Hyperactivity Disorder

This study examined potential differences between the inattentive and combined ADHD subtypes using laboratory tasks assessing behavioral inhibitory processes. Seventy-five children completed two tasks of behavioral inhibition believed to isolate different processes: the cued reaction time task (CRT), a basic inhibition task, and the go/no-go task (GNG), a complex inhibition task that incorporates motivational contingencies. Three groups of participants were identified, including ADHD/Inattentive (n = 17), ADHD/Combined (n = 37), and comparison (n = 21). Results indicated that rather than showing behavioral inhibition deficits, the ADHD/I children appeared overly inhibited, as evidenced by slower reaction times across the two tasks and significantly higher errors of omission in the GNG task. Additionally, the ADHD/I children did not demonstrate cue dependency effects on the CRT task, suggesting that they were failing to incorporate relevant information before making a response. The sluggish and inhibited performance of the ADHD/I group challenges the idea that it is a subtype of ADHD.     

Behavioral Characteristics of DSM-IV ADHD Subtypes in a School-Based Population

From an ethnically diverse sample of 2,744 school children, 221 attention deficit hyperactivity disorder (ADHD) [123 (4.5%) predominantly inattentive (IA), 47 (1.7%) predominantly hyperactive/impulsive (HI), and 51 (1.9%) combined type (C)] were identified using teacher ratings on a Diagnostic and Statistical Manual of Mental Disorders (4th ed.) (DSM-IV) symptom checklist. Subjects were compared to 221 controls on teacher ratings of behavioral, academic, and social functioning. The results revealed relatively independent areas of impairment for each diagnostic group. The IA children were impaired in all areas, but were rated as displaying more appropriate behavior and fewer externalizing problems than HI or C children. The HI group displayed externalizing and social problems, but was rated as no different than controls in learning or internalizing problems. The C group demonstrated severe and pervasive difficulties across domains. These findings support the validity of the DSM-IV ADHD subtypes; all ADHD groups demonstrated impairment relative to controls, but show different patterns of behavioral characteristics.     

Academic Achievement Over 8 Years Among Children Who Met Modified Criteria for Attention-deficit/Hyperactivity Disorder at 4–6 Years of Age

The predictive validity of symptom criteria for different subtypes of ADHD among children who were impaired in at least one setting in early childhood was examined. Academic achievement was assessed seven times over 8 years in 125 children who met symptom criteria for ADHD at 4–6 years of age and in 130 demographically-matched non-referred comparison children. When intelligence and other confounds were controlled, children who met modified criteria for the predominantly inattentive subtype of ADHD in wave 1 had lower reading, spelling, and mathematics scores over time than both comparison children and children who met modified criteria for the other subtypes of ADHD. In some analyses, children who met modified criteria for the combined type had somewhat lower mathematics scores than comparison children. The robust academic deficits relative to intelligence in the inattentive group in this age range suggest either that inattention results in academic underachievement or that some children in the inattentive group have learning disabilities that cause secondary symptoms of inattention. Unexpectedly, wave 1 internalizing (anxiety and depression) symptoms independently predicted deficits in academic achievement controlling ADHD, intelligence, and other predictors.     

Differences in cognitive control in children and adolescents with combined and inattentive subtypes of ADHD

The aim of the present study was to investigate the ability of children with attention deficit/hyperactivity disorder-combined subtype (ADHD-C) and predominantly inattentive subtype (ADHD-PI) to direct their attention and to exert cognitive control in a forced attention dichotic listening (DL) task. Twenty-nine, medication-naive participants with ADHD-C, 42 with ADHD-PI, and 40 matched healthy controls (HC) between 9 and 16 years were assessed. In the DL task, two different auditory stimuli (syllables) are presented simultaneously, one in each ear. The participants are asked to report the syllable they hear on each trial with no instruction on focus of attention or to explicitly focus attention and to report either the right- or left-ear syllable. The DL procedure is presumed to reflect different cognitive processes: perception (nonforced condition/NF), attention (forced-right condition/FR), and cognitive control (forced-left condition/FL). As expected, all three groups had normal perception and attention. The children and adolescents with ADHD-PI showed a significant right-ear advantage also during the FL condition, while the children and adolescents in the ADHD-C group showed a no-ear advantage and the HC showed a significant left-ear advantage in the FL condition. This suggests that the ADHD subtypes differ in degree of cognitive control impairment. Our results may have implications for further conceptualization, diagnostics, and treatment of ADHD subtypes.     

Social functioning and emotional regulation in the attention deficit hyperactivity disorder subtypes

Compared 16 children with attention deficit hyperactivity disorder (ADHD) combined type (ADHD-C), 14 children with ADHD predominantly inattentive type (ADHD-I), and 17 controls on parent and teacher ratings of social status and performance, self-report of social knowledge and performance, and observations of behavior on an emotional regulation task. Analyses revealed distinct patterns of social dysfunction between ADHD subgroups. Children with ADHD-C were rated as showing more aggressive behavior; furthermore, they displayed emotional dysregulation characterized by high intensity and high levels of both positive and negative behavior. In contrast, children with ADHD-I were perceived as displaying social passivity and showed deficits in social knowledge on the self-report measure but did not evidence problems in emotional regulation. Regression analyses revealed that social performance, emotional regulation, and, to a lesser degree, social knowledge, were predictive of social status. The application of these findings to understanding the nature of the social deficits in the ADHD subtypes and directions for future research are discussed.