Effects of exercise intervention on event-related potential and task performance indices of attention networks in children with developmental coordination disorder

The study investigated whether 10-week soccer training can benefit the inhibitory control and neuroelectric indices in children with developmental coordination disorder (DCD). Fifty-one children were divided into groups of typically developing (TD, n=21), DCD-training (n=16), and DCD non-training (n=14) individuals using the for Children test, and, before and after training, were assessed with the visuospatial attention orienting task with their lower extremities, while brain event-related potentials (ERPs) were concurrently recorded. The results indicated that, when compared to TD children, children with DCD responded significantly more slowly across conditions of the visuospatial attention orienting task and showed a deficit of inhibitory control capacity in their lower extremities, whereas no group differences were observed for the accuracy rate. Neuroelectric data indicated that, before training, P3 amplitude was smaller and P3 latency was slower for both DCD groups compared to TD children across conditions of the visuospatial attention orienting task; after training, the beneficial effects were seen in the strength of inhibitory control and P3 latency in the DCD-training group. The data suggest that soccer training resulted in significant improvements in ERP and task performance indices for the children with DCD.     

Children with developmental coordination disorder (DCD) and their ability to disengage ongoing attentional focus: more on inhibitory function

Children with developmental coordination disorder (DCD), along with their Control counterparts, completed two endogenous, spatial precue tasks. When the precue arrow was informative (.80) with respect to target location, the spatial precue effect results demonstrated that children with DCD take significantly longer than Control individuals to volitionally disengage (inhibit) attention from an endogenously cued location (i.e., a disengagement inhibition deficit). When the precue was uninformative (.25), we found, contrary to a common assumption, that the precue arrow automatically moved attention in the direction of the arrow, and, in addition, that DCD children may also be less able to inhibit the precued-induced urge to move attention (i.e., an initiation inhibition deficit). This type of inhibitory difficulty was also indicated for manual response inclinations produced on catch trials. Overall, DCD children appeared to have an elevated difficulty suppressing the initiation of incorrect, stimulus-provoked movement urges, be they manual or attention in nature.     

Deficits in the endogenous control of covert visuospatial attention in children with developmental coordination disorder

Deficits in the covert orienting of visuospatial attention have been reported in children with Developmental Coordination Disorder (DCD). Using two new versions of the covert orienting of visuospatial attention task (COVAT), the study presented here sought to investigate how generalised deficits are in this domain by using longer time intervals between cue and imperative stimulus. Twenty children with DCD and 20 controls were tested on two different COVATs with the interval between cue and peripheral imperative stimulus (or stimulus onset asynchrony, SOA) of 150 and 850 ms presented in a random sequence: the first used peripheral cues and no probability information (exogenous mode) and the second used central cues and an 80% probability that imperative stimuli would appear at the cued location (endogenous mode). Results showed that the time course of covert orienting to peripheral cues was normal in both groups. For central cues, however, children with DCD were more disadvantaged by invalid cues compared with controls, regardless of SOA; this finding was consistent with a deficit in the disengage operation of directing covert attention. These results confirm and extend our earlier finding that impairments in the endogenous control of covert visuospatial attention exist in children with DCD.PsycINFO classification: 2820; 2330; 2346; 3250     

Mechanisms of deficit of visuospatial attention shift in children with developmental coordination disorder: A neurophysiological measure of the endogenous Posner paradigm

The purpose of this study was to investigate and compare the mechanisms of brain activity, as revealed by a combination of the visuospatial attention shifting paradigm and event-related potentials (ERP) in children with developmental coordination disorder (DCD) and typically developing children. Twenty-eight DCD children and 26 typically developing children were recorded with regard to their behavioral performance and ERP measures during a variant of the endogenous Posner paradigm, in which they should react to visual targets preceded by spatial cues or presented uncued. Children with DCD showed longer reaction time and a deficit in inhibitory response capacity when compared to typically developing children. The electrophysiological characteristics also showed distinct modulatory effects upon attentional orienting, anticipatory mechanisms, and cognitive-to-motor transfer in children with DCD: longer cue-P3 and target-N1 latency, smaller target-P3 amplitude, an elongated interval between N2 and the motor response (N2-RT), and small areas on contingent negative variation (CNV). The combined analysis of behavioral performance and ERP data suggested that children with DCD had deficits of slower target identification (N1), less ability in interhemispheric (P3) and cognitive-to-motor transfer speed (N2-RT), as well as a less mature anticipatory and executive process (CNV).     

Mechanisms of deficit of visuospatial attention shift in children with developmental coordination disorder: A neurophysiological measure of the endogenous Posner paradigm

The purpose of this study was to investigate and compare the mechanisms of brain activity, as revealed by a combination of the visuospatial attention shifting paradigm and event-related potentials (ERP) in children with developmental coordination disorder (DCD) and typically developing children. Twenty-eight DCD children and 26 typically developing children were recorded with regard to their behavioral performance and ERP measures during a variant of the endogenous Posner paradigm, in which they should react to visual targets preceded by spatial cues or presented uncued. Children with DCD showed longer reaction time and a deficit in inhibitory response capacity when compared to typically developing children. The electrophysiological characteristics also showed distinct modulatory effects upon attentional orienting, anticipatory mechanisms, and cognitive-to-motor transfer in children with DCD: longer cue-P3 and target-N1 latency, smaller target-P3 amplitude, an elongated interval between N2 and the motor response (N2-RT), and small areas on contingent negative variation (CNV). The combined analysis of behavioral performance and ERP data suggested that children with DCD had deficits of slower target identification (N1), less ability in interhemispheric (P3) and cognitive-to-motor transfer speed (N2-RT), as well as a less mature anticipatory and executive process (CNV).     

Inhibition and attention deficit hyperactivity disorder in adults

The inhibitory account of attention deficit hyperactivity disorder (ADHD) was tested by examining the performance of college-aged adults on a variety of inhibitory tasks. The poorer performance of adults with ADHD compared with controls on negative priming, stopping, and continuous performance tasks, combined with similar group performances on a test of working memory capacity, indicates a specific inhibitory deficit as opposed to a general limitation in attentional capacity. Overall results provide evidence for extending the inhibitory deficit hypothesis to adult ADHD, not only for mechanisms of response (or motor) inhibition but also for mechanisms of cognitive inhibition.     

Increased associated movements: influence of attention deficits and movement difficulties

This study was designed to examine whether increased associated movements (AMs) reflect motor difficulties or the symptoms associated with attention disorders. Four groups of male children (N=51) aged 6-8 years participated: Group 1 consisted of 13 children diagnosed with developmental coordination disorder (DCD); Group 2 consisted of 13 children diagnosed with attention deficit hyperactivity disorder (ADHD); Group 3 consisted of 10 children diagnosed with co-occurring DCD and ADHD, and Group 4 was a control sample of 15 children, with no known movement or attention difficulties. Various AM tasks were selected from established assessments and previous research to measure AM severity. The results supported the hypothesis that increased severity of AMs reflect movement difficulties with children in the DCD and DCD/ADHD groups displaying significantly more AMs than children in the ADHD and control groups (p<.001). No differences were found between the ADHD only and control groups (p=.67) or the DCD and DCD/ADHD groups (p=.81) suggesting that AM severity is not influenced by the neurodevelopmental symptoms associated with ADHD.     

Graphomotor skills in children with developmental coordination disorder (DCD): Handwriting and learning a new letter

The aim of the present study was to analyze handwriting difficulties in children with developmental coordination disorder (DCD) and investigate the hypothesis that a deficit in procedural learning could help to explain them. The experimental set-up was designed to compare the performances of children with DCD with those of a non-DCD group on tasks that rely on motor learning in different ways, namely handwriting and learning a new letter. Ten children with DCD and 10 non-DCD children, aged 8–10 years, were asked to perform handwriting tasks (letter/word/sentence; normal/fast), and a learning task (new letter) on a graphic tablet. The BHK concise assessment scale for children’s handwriting was used to evaluate their handwriting quality. Results showed that both the handwriting and learning tasks differentiated between the groups. Furthermore, when speed or length constraints were added, handwriting was more impaired in children with DCD than in non-DCD children. Greater intra-individual variability was observed in the group of children with DCD, arguing in favor of a deficit in motor pattern stabilization. The results of this study could support both the hypothesis of a deficit in procedural learning and the hypothesis of neuromotor noise in DCD.     

The link between motor impairment level and motor imagery ability in children with developmental coordination disorder

The present study examined motor imagery ability in children with developmental coordination disorder (DCD). Specifically, it explored whether children with varying degrees of motor impairment differed in their ability to perform motor imagery tasks. Fourty-two children scoring below the 15th percentile on the Movement ABC were split into two groups--DCD severe (DCD-S), scoring on or below the 5th percentile, and DCD mild (DCD-M), scoring from the 6th to 15th percentiles--and compared to 21 age matched controls. Participants performed two motor imagery tasks--hand (performed without and with specific imagery instructions) and whole-body rotation. The results demonstrated that children in the DCD-S group had a generalized motor imagery deficit in that they were less accurate across tasks than controls (and the DCD-M group on the hand task) and showed little benefit when given specific imagery instructions. The DCD-M group appeared capable of performing simpler motor imagery transformations, but were less successful as task complexity increased. Unlike the DCD-S group, the DCD-M group did show some benefit from specific imagery instructions with increases in accuracy on the hand task. These results suggest that a motor imagery deficit does exist in many children with DCD but that its presentation can vary--factors such as the individual child's level of motor impairment and task complexity appear to be linked to the profile of deficits observed, which could explain the inconsistent findings of previous studies. Although this study lends support to the theory that a deficit in internal modeling is an underlying problem for children with DCD, still more research is required to develop the theory further.     

Oculomotor atypicalities in Developmental Coordination Disorder

Children with Developmental Coordination Disorder (DCD) fail to acquire adequate motor skill, yet surprisingly little is known about the oculomotor system in DCD. Successful completion of motor tasks is supported by accurate visual feedback. The purpose of this study was to determine whether any oculomotor differences can distinguish between children with and without a motor impairment. Using eye tracking technology, visual fixation, smooth pursuit, and pro‐ and anti‐saccade performance were assessed in 77 children that formed three groups: children with DCD (aged 7–10), chronologically age (CA) matched peers, and a motor‐match (MM) group (aged 4–7). Pursuit gain and response preparation in the pro‐ and anti‐saccade tasks were comparable across groups. Compared to age controls, children with DCD had deficits in maintaining engagement in the fixation and pursuit tasks, and made more anti‐saccade errors. The two typically developing groups performed similarly, except on the fast speed smooth pursuit and antisaccade tasks, where the CA group outperformed the younger MM group. The findings suggest that children with DCD have problems with saccadic inhibition and maintaining attention on a visual target. Developmental patterns were evident in the typically developing groups, suggesting that the pursuit system and cognitive control develop with age. This study adds to the literature by being the first to systematically identify specific oculomotor differences between children with and without a motor impairment. Further examination of oculomotor control may help to identify underlying processes contributing to DCD. A video abstract of this article can be viewed at: https://youtu.be/NinXa2KlB4M . [Correction added on 27 January 2017, after first online publication: The video abstract link was added.]     

Information processing and speech lateralization in learning-disabled children

The relationship between information processing and speech lateralization was investigated in learning-disabled children. The Kaufman Assessment Battery for Children (K-ABC) assessed simultaneous and successive processing while a dichotic listening paradigm with free recall and directed attention conditions assessed speech lateralization. A three-factor ANOVA design conducted on the dichotic data revealed that normal children demonstrated stronger right ear advantage (REA); whereas learning-disabled showed weaker right ear advantage. Further, lambda analyses conducted on individual subjects revealed that the learning-disabled did not demonstrate the REA, were not biased attenders, and did not get more right ear than left ear items when attention was directed to one ear. Multiple-regression analysis was used to predict sequential processing from the dichotic data for both groups. Learning-disabled children demonstrated a substantial deficit in sequential processing as compared to normal children. These results indicate that learning-disabled children may not have adequate cerebral lateralization of receptive speech processes, shift their attention more readily, and are more inadequate in sequential processing that presumably subserves language functioning. Perhaps learning-disabled children have deficiencies of processor capacity of salient areas of the left (language) hemisphere.     

On the ability of children with developmental coordination disorder (DCD) to inhibit response initiation: the simon effect

The ability of children with developmental coordination disorder (DCD) to inhibit the initiation of an incorrect manual response urge was examined using a typical Simon task. While the size of the Simon effect was the same for both DCD (N = 20) and Control (N = 20) groups of children, showing no difference with respect to the time needed to complete the inhibition an unwanted response, children with DCD produced significantly more errors of the type which reflected a reduced ability to successfully effect the inhibition operation when it was required. This result is consistent with some earlier findings pointing to an inhibitory deficit for children with DCD (Wilson & Maruff, 1999).     

A comparison of working memory profiles in children with ADHD and DCD

The main objective of present study was to investigate whether the patterns of working memory performance differ as a function of attention and motor difficulties, and whether children with ADHD and DCD could be reliably discriminated on the basis of their memory deficits. A related aim was to investigate the link between their working memory profiles and academic attainment. Fifty children with ADHD-Combined, 55 children with DCD, and an age-matched group of 50 typically developing children with average working memory were assessed on standardized measures of working memory, IQ, and academic attainment (reading, spelling, comprehension, and math). The normal controls performed significantly better than both clinical groups on all working memory tests. Specific patterns emerged in the memory profile of the clinical groups: The children with DCD had a depressed performance in all working memory tests, with particularly low scores in visuospatial memory tasks; children with ADHD performed within age-expected levels in short-term memory but had a pervasive working memory deficit that impacted both verbal and visuospatial domains. The clinical groups could reliably be discriminated on the basis of their short-term memory scores. Their learning profiles were similar. It is possible that the working memory profiles of the children with ADHD and DCD are influenced by distinct underlying cognitive mechanisms, rather than a general neurodevelopmental delay. Despite these distinctive patterns of memory performance, both clinical groups performed similarly on academic attainments, suggesting that memory may underlie learning difficulties, independent of related clinical disorders.     

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     

Action planning and position sense in children with Developmental Coordination Disorder

The present study examined action planning and position sense in children with Developmental Coordination Disorder (DCD). Participants performed two action planning tasks, the sword task and the bar grasping task, and an active elbow matching task to examine position sense. Thirty children were included in the DCD group (aged 6–10 years) and age-matched to 90 controls. The DCD group had a MABC-2 total score ⩽5th percentile, the control group a total score ⩾25th percentile. Results from the sword-task showed that children with DCD planned less for end-state comfort. On the bar grasping task no significant differences in planning for end-state comfort between the DCD and control group were found. There was also no significant difference in the position sense error between the groups. The present study shows that children with DCD plan less for end-state comfort, but that this result is task-dependent and becomes apparent when more precision is needed at the end of the task. In that respect, the sword-task appeared to be a more sensitive task to assess action planning abilities, than the bar grasping task. The action planning deficit in children with DCD cannot be explained by an impaired position sense during active movements.     

Co-occurring disorders: a possible key to visual perceptual deficits in children with developmental coordination disorder?

A study was conducted to examine how visual perceptual functioning in children with DCD may be influenced by co-occurring learning problems such as reading disabilities (RD) and/or attention deficit hyperactivity disorder (ADHD). Participants included seven groups of children: 27 children with DCD only, 11 with ADHD only, 14 with RD only, 63 with DCD and at least one other disorder (i.e., DCD + ADHD, DCD + RD, DCD + ADHD + RD), and 73 typically developing controls. Visual perceptual skills were assessed using the Test of Visual Perceptual Skills (TVPS) and the Rey Osterreith Complex Figure (ROCF; copy and delayed recall). Children with DCD and at least one other disorder were found to have impairments on the TVPS compared to children with DCD only, ADHD only, and typically developing controls, particularly on subtests assessing visual memory. On the ROCF, children with DCD and at least one other disorder scored significantly lower than children with ADHD only or RD only. Children with DCD plus one other disorder were then subdivided into three groups: DCD + ADHD, DCD + RD, and DCD + ADHD + RD and compared to children with DCD only, ADHD only, and RD only. Results indicated that children with DCD + ADHD + RD had significant impairments on the TVPS compared to children with DCD only and children with ADHD only. On the ROCF, children with DCD + ADHD + RD scored significantly lower than all of the groups, except the DCD+RD group. These findings suggest that DCD on its own is not associated with visual perceptual problems; rather, it is the presence of co-occurring disorders that is a possible key to visual perceptual deficits in children with DCD. The number of co-occurring disorders present with DCD is associated with the severity of the visual perceptual dysfunction. Deficits in visual memory skills appear to be a specific area of difficulty for children with DCD and co-occurring RD and/or ADHD.     

Attaining and maintaining preparation: A comparison of attention in hyperactive,normal, and disturbed control children

The hypothesis that hyperactive children have a deficit in sustained attention was investigated. Eighteen children who had attention deficit disorder with hyperactivity (ADDH), aged 7 to 11 years, were compared with children who had conduct disorder (n = 15), mixed conduct disorder and ADDH (n = 26), emotional disorder (n = 18), or learning disability (n = 22), and with normal controls (n = 15). The subjects were tested on three versions of the Continuous Performance Task. Sustained attention was assessed from performance with increasing time on task and from ability to prepare attention in response to a warning. Performance of all subjects deteriorated with increasing time and improved with the opportunity to prepare attention. Hyperactive subjects were not more adversely affected by increasing time, nor did they benefit less than controls from the opportunity to prepare attention. Data reanalysis after rediagnosis according to ICD-9 criteria did not change the results. This study did not confirm the hypothesis that hyperactive children have a unique sustained attention deficit.     

Lack of Inhibition: A Motivational Deficit in Children With Attention Deficit/Hyperactivity Disorder and Children With Traumatic Brain Injury*

Recent research has demonstrated that both brain-injured children and children with attention deficit/hyperactivity disorder (ADHD) suffer from response inhibition deficits. To investigate whether these deficits can be influenced by motivational factors, the stop-signal task was performed with and without reward contingencies for successful inhibition. Three groups of children between 8 and 12 years of age, participated in the study: 31 children with ADHD, 37 with traumatic brain injuries (TBI), and 26 normal controls. Results indicated that, although all groups showed comparable learning effects, reward contingencies had different effects on the groups. Whereas the performance of children with ADHD under reward contingencies were brought up to the performance level of normal controls, rewards were found less effective at improving response inhibition in children with TBI. The results further support a motivational/energetic explanation of the inhibitory deficit in children with ADHD, and of a primary response inhibition deficit due to structural brain damage in children with TBI.     

Lack of inhibition: a motivational deficit in children with attention deficit/hyperactivity disorder and children with traumatic brain injury.

Recent research has demonstrated that both brain-injured children and children with attention deficit/hyperactivity disorder (ADHD) suffer from response inhibition deficits. To investigate whether these deficits can be influenced by motivational factors, the stop-signal task was performed with and without reward contingencies for successful inhibition. Three groups of children between 8 and 12 years of age, participated in the study: 31 children with ADHD, 37 with traumatic brain injuries (TBI), and 26 normal controls. Results indicated that, although all groups showed comparable learning effects, reward contingencies had different effects on the groups. Whereas the performance of children with ADHD under reward contingencies were brought up to the performance level of normal controls, rewards were found less effective at improving response inhibition in children with TBI. The results further support a motivational/energetic explanation of the inhibitory deficit in children with ADHD, and of a primary response inhibition deficit due to structural brain damage in children with TBI.     

Contributions of trunk muscles to anticipatory postural control in children with and without developmental coordination disorder

Current evidence suggests that movement quality is impacted by postural adjustments made in advance of planned movement. The trunk inevitably plays a key role in these adjustments, by creating a stable foundation for limb movement. The purpose of this study was to examine anticipatory trunk muscle activity during functional tasks in children with and without developmental coordination disorder (DCD). Eleven children with DCD (age 7 to 14 years) and 11 age-matched, typically-developing children performed three tasks: kicking a ball, climbing stairs, and single leg balance. Surface electromyography (EMG) was used to examine the neuromuscular activity of bilateral transversus abdominis/internal oblique, external oblique and L3/4 erector spinae, as well as the right tibialis anterior and rectus femoris muscles. Onset latencies for each muscle were calculated relative to the onset of rectus femoris activity. In comparison to the children with DCD, the typically-developing children demonstrated earlier onsets for right tibialis anterior, bilateral external oblique, and right transversus abdominis/internal oblique muscles. These results suggest that anticipatory postural adjustments may be associated with movement problems in children with DCD, and that timing of both proximal and distal muscles should be considered when designing intervention programs for children with DCD.