Rapid automatized naming (RAN) in children with ADHD: An ex-Gaussian analysis

Children with ADHD demonstrate increased frequent “lapses” in performance on tasks in which the stimulus presentation rate is externally controlled, leading to increased variability in response times. It is less clear whether these lapses are also evident during performance on self-paced tasks, e.g., rapid automatized naming (RAN), or whether RAN inter-item pause time variability uniquely predicts reading performance. A total of 80 children aged 9 to 14 years—45 children with attention-deficit/hyperactivity disorder (ADHD) and 35 typically developing (TD) children—completed RAN and reading fluency measures. RAN responses were digitally recorded for analyses. Inter-stimulus pause time distributions (excluding between-row pauses) were analyzed using traditional (mean, standard deviation [SD], coefficient of variation [CV]) and ex-Gaussian (mu, sigma, tau) methods. Children with ADHD were found to be significantly slower than TD children (p < .05) on RAN letter naming mean response time as well as on oral and silent reading fluency. RAN response time distributions were also significantly more variable (SD, tau) in children with ADHD. Hierarchical regression revealed that the exponential component (tau) of the letter-naming response time distribution uniquely predicted reading fluency in children with ADHD (p < .001, ΔR² = .16), even after controlling for IQ, basic reading, ADHD symptom severity and age. The findings suggest that children with ADHD (without word-level reading difficulties) manifest slowed performance on tasks of reading fluency; however, this “slowing” may be due in part to lapses from ongoing performance that can be assessed directly using ex-Gaussian methods that capture excessively long response times.     

Poorer divided attention in children born very preterm can be explained by difficulty with each component task,not the executive requirement to dual-task

Children born very preterm (VP, ≤ 32 weeks) exhibit poor performance on tasks of executive functioning. However, it is largely unknown whether this reflects the cumulative impact of non-executive deficits or a separable impairment in executive-level abilities. A dual-task paradigm was used in the current study to differentiate the executive processes involved in performing two simple attention tasks simultaneously. The executive-level contribution to performance was indexed by the within-subject cost incurred to single-task performance under dual-task conditions, termed dual-task cost. The participants included 77 VP children (mean age: 7.17 years) and 74 peer controls (mean age: 7.16 years) who completed Sky Search (selective attention), Score (sustained attention) and Sky Search DT (divided attention) from the Test of Everyday Attention for Children. The divided-attention task requires the simultaneous performance of the selective- and sustained-attention tasks. The VP group exhibited poorer performance on the selective- and divided-attention tasks, and showed a strong trend toward poorer performance on the sustained-attention task. However, there were no significant group differences in dual-task cost. These results suggest a cumulative impact of vulnerable lower-level cognitive processes on dual-tasking or divided attention in VP children, and fail to support the hypothesis that VP children show a separable impairment in executive-level abilities.     

Parental Guidance and Children's Executive Function: Working Memory and Planning as Moderators During Joint Problem‐Solving

Cognitive aspects of children's executive function (EF) were examined as moderators of the effectiveness of parental guidance on children's learning. Thirty‐two 5‐year‐old children and their parents were observed during joint problem‐solving. Forms of guidance geared towards cognitive assistance were coded as directive or elaborative, and children's responses were recorded. Children were then assessed on an independent version of the same task. A parent‐rated composite of working memory and planning was used as a measure of EF. Directive guidance by parents was associated with more child errors during the joint activity, whereas elaborative guidance was associated with better performance. Parent‐rated EF moderated the relation, such that the relation between elaborative guidance and better performance was only significant for children with low EF. During the independent task, EF again moderated the relation between parent guidance and children's performance, such that children with low EF did worse when parents had provided more directive guidance; for children with high EF, directive guidance was associated with better independent performance. These findings suggest that the extent to which children's performance relates to different forms of parents' guidance varies, and elaborative assistance may be more helpful for children with low EF. Copyright © 2016 John Wiley & Sons, Ltd.     

Self‐Regulation: Relations with Theory of Mind and Social Behaviour

It is argued that self‐regulation skill is necessary both for displaying constructive behaviour and for controlling negative social behaviour, and self‐regulation might affect social behaviours by increasing the ability to understand others' minds. In this research, in order to examine different aspects of self‐regulation and their similarities and differences in terms of their relations with other constructs, we focused on both effortful control and executive function and investigated their concurrent associations with socially competent and aggressive behaviours and theory of mind (ToM). The participants were 212 preschool children in Turkey. We assessed executive functions with behavioural measures and effortful control with mother reports. We used six tasks for comprehensive assessment of mental state understanding. Children's social competency and aggressive behaviour were assessed with teacher reports. Structural equation modelling results showed that when age and receptive language were controlled, ToM was significantly associated with social competence but not aggressive behaviour. Both effortful control and executive functions were significantly related to social competency and ToM; the pathways from each self‐regulation skill were similar in strength. ToM was linked with social competence, but it did not have a mediating role in the relations of self‐regulation with social competence. The findings highlighted the importance of self‐regulation for socio‐cognitive and social development in the preschool years. Copyright © 2016 John Wiley & Sons, Ltd.     

Executive function in paediatric medulloblastoma: The role of cerebrocerebellar connections

Executive functions (EFs) are involved in the attainment, maintenance, and integration of information; these functions may play a key role in cognitive and behavioural outcomes in children treated for medulloblastoma (MB). At present, it remains unclear which EFs are most sensitive to the treatment effects for MB and whether damage to cerebrocerebellar circuitry is associated with EF. We completed a comprehensive evaluation of EF in 24 children treated for MB and 20 age‐matched healthy children (HC) and distilled these measures into components. Six components (C1–C6) were extracted from our model, reflecting dissociable constructs of EF: C1 = cognitive efficiency; C2 = planning/problem‐solving; C3 = positive cognitive emotion regulation; C4 = working memory; C5 = negative cognitive emotion regulation; and C6 = mixed cognitive emotion regulation. Group differences were found for C1, C2, C3, and C4; the MB group showed poorer performance on EF tasks and made less use of positive cognitive emotion regulation strategies relative to HC. Compromise to cerebrocerebellar microstructure – cerebro‐ponto‐cerebellar and cerebello‐thalamo‐cerebral pathways – was evident in children treated for MB compared to HC. We found that cerebrocerebellar circuitry has a mediating effect on one component of EF following treatment for MB – working memory.     

Clustering and switching in unconstrained,phonemic and semantic verbal fluency: the role of age and school type

We investigated the role of age and school type on clustering and switching in verbal fluency tasks (VFTs) with Brazilian children. The children were administered unconstrained, phonemic and semantic VFTs with a duration of 150 or 120 s, respectively. Both age and school type influenced all variables and in terms of performance over time. Older children and private school students outperformed the remainder of the sample, with the first 30 s of each VFT usually being the most productive. Although the size of the clusters produced did not differ between groups, the types of clusters did show some variations, with semantic clusters being the most frequent. Our results revealed strong correlations between switching ability and word production in all three VFTs. In conclusion, the executive functions known as planning and cognitive flexibility play a crucial role in word production by organising and facilitating the recall of lexical information from memory.     

3岁幼儿抑制和工作记忆的可分离性研究

尽管成年期个体的执行功能结构被认为是可分离的,然而,学龄前儿童的抑制和工作记忆的可否分离还存在争议。本文使用验证性因子分析研究181名三岁儿童执行功能的主要成分抑制和工作记忆的可分离性。抑制测查采用包礼物任务、糖果延迟任务和昼夜Stroop任务,工作记忆测查采用找贴画任务、Beads任务和数点数任务。通过探索性和验证性因素分析显示:3岁幼儿的测验任务数据更为拟合抑制和工作记忆两因素结构模型, 这说明三岁幼儿的抑制和工作记忆是独立发挥作用的,抑制和工作记忆功能早在学龄前期就已分离, 并且通过测量恒等性检验发现无性别差异。     

不同强度短时有氧运动对执行功能的影响

探讨短时有氧运动对执行功能的影响是否与运动强度和性别有关, 为从运动强度和性别角度选择合理的有氧运动干预方案改善执行功能提供基础。研究采用混合设计, 选取30名大学生(男女人数各半), 使用功率自行车实施30分钟的不同强度有氧运动, 使用Flanker任务、2-back任务和数字More-odd shifting任务分别测查被试基线、小强度短时有氧运动、中强度短时有氧运动和大强度短时有氧运动后执行功能的抑制、刷新和转换三个子功能的变化, 结果表明：不同强度的短时有氧运动对执行功能产生选择性的积极影响, 且不随性别变化而改变。     

预先信息的不确定性与准备时间对任务切换的影响

为揭示任务切换中切换代价的本质, 考察了预先信息与准备时间对任务切换的影响, 结果发现: (1) 预先信息对任务切换有显著的影响效应, 全部信息的反应时和切换代价显著低于无信息和部分信息的反应时和切换代价, 而后二者之间无显著差异; (2) 预先信息的影响效应受到准备时间的调节作用, 在准备时间为100ms时, 预先信息无显著的影响效应, 而在准备时间达到600ms以后, 预先信息的准备效应显著。这说明, 预先信息影响的认知加工是任务设置重构, 并且这种影响效应受到准备时间的调节作用。     

视觉表象扫描的概念控制

将表象扫描和概念提示范式相结合, 在三个实验中通过考察概念控制下表象扫描加工中的参照系冲突效应以及概念参照系的优先性, 进而揭示表象扫描加工中的自上而下控制机制。结果发现：(1) 正立或旋转方位汉字提示下表象扫描加工中出现了参照轴效应, 箭头提示下不存在这种效应, 表明不同提示引发了不同空间关系计算过程; (2) 在表象扫描概念控制过程中, 概念参照系、环境(重力)参照系及提示汉字内在参照系同时被激活, 它们可能处于不同冲突状态, 解决这些冲突具有不同认知代价; (3) 在解决不同参照系冲突过程中, 反映自上而下加工的概念参照系总能通过抑制其它参照系而取得优先地位, 表明人的认知系统能够对表象加工进行自上而下的主动控制, 这种主动控制反映了一种执行功能。