Motor, visual and egocentric transformations in children with Developmental Coordination Disorder

AIM: This study aimed to test the internal modelling deficit (IMD) hypothesis using the mental rotation paradigm. BACKGROUND: According to the IMD hypothesis, children with Developmental Coordination Disorder (DCD) have an impaired ability to internally represent action. Thirty-six children (18 DCD) completed four tasks: two versions of a single-hand rotation task (with and without explicit imagery instructions), a whole-body imagery task and an alphanumeric rotation task. RESULTS: There was partial support for the hypothesis that children with DCD would display an atypical pattern of performance on the hand rotation task, requiring implicit use of motor imagery. Overall, there were no significant differences between the DCD and control groups when the hand task was completed without explicit instructions, on either response time or accuracy. However, when imagery instructions were introduced, the controls were significantly more accurate than the DCD group, indicating that children with DCD were unable to benefit from explicit cuing. As predicted, the controls were also significantly more accurate than the DCD group on the whole-body task, with the accuracy of the DCD group barely rising above chance. Finally, and as expected, there was no difference between the groups on the alphanumeric task, a measure of visual (or object-related) imagery. CONCLUSIONS: The inability of the DCD group to utilize specific motor imagery instructions and to perform egocentric transformations lends some support to the IMD hypothesis. Future work needs to address the question of whether the IMD itself is subgroup-specific.     

Rhythmic coordination of hand and foot in children with Developmental Coordination Disorder

BACKGROUND: Children with Developmental Coordination Disorder (DCD) have difficulties producing stable rhythmic bimanual coordination patterns in comparison with age-related peers. Rhythmic coordination of non-homologous limbs (e.g. hand and foot) is even more difficult to perform because of mechanical differences between the limbs. The aim of the present study is to investigate the stability of hand-foot coordination patterns of children with DCD. METHODS: Ten children with DCD (mean age 7.0 years, SD 1.1 years) and 16 control children (mean age 7.4 years, SD 1.3 years) participated in the study. They were asked to perform in-phase or anti-phase tapping movements in three different interlimb coordination combinations: (1) hand-hand (homologous), (2) hand-foot same body side (ipsilateral), and (3) hand-foot different body side (contralateral). Coordination stability was measured by the variability of the relative phase between the limbs under a 'steady state' (preferred) frequency condition, and by the critical frequency (i.e. the point at which loss of pattern stability was observed) in a condition in which the movement frequency was 'scaled' up (only anti-phase tapping). RESULTS: Coordination patterns of children in the DCD group were less stable in all three limb combinations compared with controls. Further, hand-foot coordination patterns were less stable than hand-hand coordination patterns. With regard to hand-foot coordination, ipsilateral patterns were equally stable compared with contralateral patterns in the in-phase task, but less stable in the anti-phase task. No differential effects were found between the DCD and control groups across the different limb combinations, except for steady-state anti-phase coordination in the ipsilateral limb condition. This effect was due to a relatively good performance of the control children in this condition in comparison with the other limb combination conditions. CONCLUSIONS: Children with DCD have difficulties producing stable rhythmic hand-foot coordination patterns compared with control children.     

Visual contribution to walking in children with Developmental Coordination Disorder

BACKGROUND: The motor co-ordination problems of children with Developmental Coordination Disorder (DCD) have been frequently associated with poor visuospatial processing. In order to extend these findings mainly based on fine motor experiments, the present study investigates the contribution of vision to the control of walking in children with DCD. METHODS: Children with DCD (n = 12) walked at their preferred speed on a straight, firm and uncluttered walkway in a condition with normal lighting and in a dark condition. Spatiotemporal gait variables were assessed by means of a three-dimensional ProReflex camera system and compared with the gait pattern of matched, typically developing (TD) children (n = 12). RESULTS: In normal lighting, the gait pattern of both groups was similar, with the exception of subtle differences in the temporal phasing, showing a slightly longer support phase in the children with DCD. In the dark, step frequency and step length were decreased in the children with DCD, resulting in a significantly slower walking velocity. In addition, the medio-lateral excursion of the centre of mass tended to increase in this group. In the TD children, adaptations to the spatiotemporal pattern remained absent. CONCLUSIONS: These results suggest that children with DCD are more dependent on global visual flow information than TD children for the maintenance of balance and the control of velocity during walking. This increased dependency on visual control might be associated with a poorly developed internal sensorimotor model.     

Stability and change in children with Developmental Coordination Disorder

BACKGROUND: Children with Developmental Coordination Disorder (DCD) are a heterogeneous group who have a marked impairment in the performance of functional motor skills. Provision for these children is usually made via a paediatrician through occupational or physiotherapy; though with a prevalence rate of 5%, regular provision is rarely possible because of limited professional resources. METHODS: This study covers a period of nearly 4 years and initially examined a group of 31 children first identified as having DCD at 7-9 years of age. The children were observed and assessed before, during and after a total of 16 weeks of intervention carried out by parents and teachers. This was followed by a period of monitoring of performance for 26 of the children in the motor domain plus other abilities such as educational progress and self-concept. Individual children were tracked using a variety of qualitative and quantitative approaches, building up longitudinal whole child profiles. RESULTS: Following intervention, 14 of the 26 children have shown improvement and stability in all areas and no longer display DCD symptoms. Eight children have profiles which have shown variability, with the children moving in and out of the DCD classification, while the remaining four children have consistently scored poorly in their movement skills and in addition received ongoing support in school for academic subjects. CONCLUSIONS: The study has confirmed that children with DCD show varying profiles over a period of time and that the profiles have distinct characteristics related to events in the child's life. This approach to examining stability and change in the progressions of children's difficulties is in keeping with an ecological approach to explaining development with its multilayered influences creating changes.     

Problems in the coupling of eye and hand in the sequential movements of children with Developmental Coordination Disorder

BACKGROUND: Shifting gaze and attention ahead of the hand is a natural component in the performance of skilled manual actions. Very few studies have examined the precise co-ordination between the eye and hand in children with Developmental Coordination Disorder (DCD). METHODS: This study directly assessed the maturity of eye-hand co-ordination in children with DCD. A double-step pointing task was used to investigate the coupling of the eye and hand in 7-year-old children with and without DCD. Sequential targets were presented on a computer screen, and eye and hand movements were recorded simultaneously. RESULTS: There were no differences between typically developing (TD) and DCD groups when completing fast single-target tasks. There were very few differences in the completion of the first movement in the double-step tasks, but differences did occur during the second sequential movement. One factor appeared to be the propensity for the DCD children to delay their hand movement until some period after the eye had landed on the target. This resulted in a marked increase in eye-hand lead during the second movement, disrupting the close coupling and leading to a slower and less accurate hand movement among children with DCD. CONCLUSIONS: In contrast to skilled adults, both groups of children preferred to foveate the target prior to initiating a hand movement if time allowed. The TD children, however, were more able to reduce this foveation period and shift towards a feedforward mode of control for hand movements. The children with DCD persevered with a look-then-move strategy, which led to an increase in error. For the group of DCD children in this study, there was no evidence of a problem in speed or accuracy of simple movements, but there was a difficulty in concatenating the sequential shifts of gaze and hand required for the completion of everyday tasks or typical assessment items.     

A pilot study of psychopathology in Developmental Coordination Disorder

BACKGROUND: This paper explores the prevalence of emotional and behavioural disorders in children referred to a Community Paediatric Occupational Therapy service for assessment and treatment of problems with development of motor skills. METHODS: Parents of 47 children from a clinical sample of children who had been identified with Developmental Coordination Disorder (DCD) returned the Strengths and Difficulties Questionnaire (SDQ)--a brief measure of the pro-social behaviour and psychopathology that can be completed by parents, teachers or youths. RESULTS: Significant emotional and behavioural problems were reported by 29 parents (62%) with a further six (13%) reporting problems in the borderline range. Seven children (15%) were without significant problems in one or more area although only four of these (9%) were outside the borderline range for all of the sub-domains of the SDQ. DISCUSSION: A significant proportion of children with DCD were reported by their parents to be at risk of psychopathology. Further research is needed to understand the relationship between motor difficulties and emotional and behavioural symptoms; however, it is recommended that interventions for children with DCD should support mental health and behavioural problems as well as motor development.     

Children with Developmental Coordination Disorder respond similarly to age-matched controls in both speed and accuracy if goal-directed movements are made across the midline

BACKGROUND: The conventional view among many clinicians is that crossing the midline in children with Developmental Coordination Disorder (DCD) results in degradation of their performance. However, no kinematic data yet exist to support this view. We therefore tested this assumption in an experimental setting. METHODS: A group of age- and gender-matched children with DCD (n = 48) and a group of typically developing children (n = 48) were compared while performing goal-directed movements with a pen on a XY-tablet. We examined whether speed or accuracy changed if the goal-directed movements were made towards targets positioned either at the midline, the contralateral (crossed) side or the ipsilateral (uncrossed) side of the body midline. RESULTS: Our results showed that movements in the contralateral workspace were less accurate for both groups of children in the tested age range (6-11 years). The movements made towards the targets in the midline were the fastest, and the pen pressure for movements in the ipsilateral space was the highest. However, these effects were similar for children with and without DCD. As expected, children with DCD made more errors, were slower and pressed more erratically on their pen, but this difference was irrespective of the position of their hand in the workspace. CONCLUSION: Crossing the midline in children with DCD for small amplitude movements (2.5 cm), as tested in this study, does not result in increased degradation of the goal-directed movements compared with their typically developing peers. This implies that, contrary to expectation, there is no evidence for a preferential deficit in DCD in brain structures involved in making movements in the contralateral workspace.     

儿童发育性协调障碍问卷中文版的应用研究

目的进行发育性协调障碍问卷中文版(DCDQ-C)的信效度评价,为进一步在中国大陆地区开展发育性协调障碍早期筛查提供有效的筛查工具。方法苏州市区的10所幼儿园共3 316名儿童纳入研究。采用Cronbach'α系数来确定内部一致性信度,Person相关系数评价DCDQ-C的重测信度,项目水平内容效度指数(I-CVI)评价内容效度。探索性因素分析来检验DCDQ-C测试的结构效度。采用工作者曲线(ROC)下面积分析DCDQ-C的诊断价值。结果 DCDQC内部一致性(所有项目Cronbach'α值均0.85)和重测信度(13项相关系数均在0.9以上)都非常高。所有项目的I-CVI均0.78,表明DCDQ-C内容的可靠性价高。探索性因素分析的因子载荷基本均在0.7以上,提示DCDQ-C的结构效度较高。DCDQ-C的ROC曲线下面积与0.5具有统计学差异(P0.05),但曲线下面积不高(0.641),去除低年龄组后ROC曲线下面积略有增加。结论中文版本的DCDQ在中国儿童中应用性较好,但在小年龄段的学龄前儿童使用时仍需谨慎。     

儿童精神障碍患者的脑电图回顾性分析

目的：探讨儿童精神障碍患者的特点,为更好地诊断和治疗提供依据。方法采用回顾性研究,对2009年1月至2012年1月在西安市精神卫生中心住院的362例儿童精神障碍患者进行普通脑电图和24小时脑电图检查,并对结果进行分析。结果362例患者中,普通脑电图检查正常的患者278例,占76．80％,异常的患者84例,占23．20％,异常者符合癫痫的脑电图改变;24小时脑电图检查大致正常的34例,占9．39％,异常的患者328例,占90．61％,异常者均符合癫痫的脑电图改变;24小时脑电图对癫痫患者的检出率较普通脑电图更高（χ2＝330．68,P＜0．05）。结论儿童精神障碍患者脑电图异常符合癫痫患者的脑电图改变,儿童精神障碍为癫痫所伴发的精神障碍。     

Perception-action coupling in children with and without DCD: Frequency locking between task-relevant auditory signals and motor responses in a dual-motor task

BACKGROUND: The current research examines the relationship between perceptual and motor processes, known as perception-action or sensorimotor coupling, and the potential differences in perception-action coupling among children with and without Developmental Coordination Disorder (DCD) and adults in a gross-motor co-ordination task (clapping while marching) when a task-relevant driving sensory signal is present. METHODS: Ten children with DCD (7.32 + 0.23 years), eight typically developing (TD) children who were age-, gender- and racially/ethnically matched (6.91 + 0.24 years) and 10 college-aged adults were participants in this study. Participants clapped and marched to an auditory beat at four different frequencies: 0.8, 1.2,1.6 and 2.0 Hz. The relative timing measures of mean relative phase (MRP) and variability of relative phase (VRP) were calculated and compared using 3 (group) x 4 (frequency) x 2 (limb) anovas. Qualitatively, participants were assessed for the presence of absolute coupling (100% + 15% MRP). RESULTS: Statistically significant differences in MRP occurred for coupling, frequency and group, and post hoc analysis indicated that the adult group differed from both the DCD and TD groups, who did not differ from each other. In VRP, there were significant main effects for coupling and group, and a significant interaction between group and frequency, with post hoc analysis indicating the DCD group to be different from the TD and adult groups. Qualitatively, both the adult and TD groups increased in the number of participants who adopt absolute coupling as frequency increases. In contrast, the DCD participants adopt this absolute coupling far less frequently overall; in fact, the number of participants adopting this pattern decreases as frequency increases. CONCLUSIONS: These results indicate that children with DCD have difficulties with both the co-ordination and the control of their perception-action coupling for this particular task.     

The development and standardization of the Children Activity Scales (ChAS-P/T) for the early identification of children with Developmental Coordination Disorders

BACKGROUND: Previous studies have emphasized the importance of early identification of children with Developmental Coordination Disorder (DCD) to prevent the development of secondary academic, emotional and social manifestations of the disorder. The aim of this study was to develop a valid parent and teacher questionnaire--the Children Activity Scales for parents (ChAS-P) and for teachers (ChAS-T)--to identify children aged 4-8 years at risk for DCD and to examine the reliability and validity of these questionnaires. METHODS: The questionnaires' content and face validity were established, and then cut-off scores were determined based on responses of 355 teachers and 216 parents. Internal consistencies were also calculated. Factor analyses were performed, and construct validity was determined by examining the questionnaires' ability to discriminate between 30 children aged 5-6.5 years diagnosed with DCD and 30 typically developing children. Concurrent validity was examined by comparing questionnaire scores with those of the Movement Assessment Battery for Children (M-ABC). RESULTS: High values were obtained for internal consistency (0.96-0.94) for the ChAS-T and the ChAS-P respectively. Factor analysis revealed four distinct factors within the ChAS-P and three within the ChAS-T, reinforcing the theoretical validity of the items selected and appropriateness for identifying DCD. Construct validity was indicated by finding significant differences between the groups' scores on the ChAS-T and the ChAS-P. Significant correlations between the children's scores on the questionnaires and those of the M-ABC confirmed their concurrent validity. CONCLUSIONS: Initial results suggest that the ChAS-T and Chas-P are reliable tools to identify children at risk for DCD.     

Constraints and facilitators to participation in physical activity in teenagers with Developmental Co‐ordination Disorder: an exploratory interview study

Background Despite their movement difficulties, youngsters with Developmental Co‐ordination Disorder (DCD) generally have sufficient capability for physical activity. However, they tend to be less physically active and less physically fit than their well co‐ordinated age peers. The aim of this study was to use qualitative research methods to understand which factors constrain and facilitate participation in physical activity in teenagers with DCD, in order to help inform future health promotion programmes. Method Semi‐structured interviews were conducted with eight teenagers with DCD (aged 13–15) and their parents. The interviews focused on how much physical activity was typically undertaken by the child and the perceived constraints and facilitators to being physically active. Interviews were transcribed and subjected to categorical‐content analysis. Results Half of the children and all but one of the parents reported that the children did little physical activity. Although most children disliked competitive team games, they reported many physical activities that they did enjoy and they reported wanting to be more physically active. Perceived internal constraints to participation included poor motor skill, lack of motivation and reports of fatiguing easily. Perceived external constraints included difficulty travelling to activities, negative comments from peers and teachers' lack of understanding of DCD. Conclusions Reports of low levels of physical activity support previous literature and are a cause for concern for this group. The teenagers expressed the desire to be more active, yet the interviews revealed both personal and environmental constraints to engagement in physical activity. It is clear that these factors interact in a dynamic way and that teachers, schools and communities play an important role in creating a motivational environment for youngsters with DCD to engage in physical activity and learn to maintain an active lifestyle as they move into adulthood.     

The role of mental simulation in embodied cognition

Whereas much has been reported on the subject of embodied cognition (EC), specifics regarding the link between cognitive processes and bodily action remain a mystery, especially regarding its developmental nature. This commentary presents the perspective that in addition to providing insight to how children mentally represent their intentions, an understanding of action simulation has the potential to inspire new thoughts on EC. The basis for this line of reasoning is that one of the primary mechanisms shared by EC and the ability to mentally represent action is simulation. Furthermore, research reports provide a convincing case that motor imagery provides a window into the process of mental (action) representation. With this paper I describe the role of simulation with both processes and suggest that simulation testing in the form of imagery use has the potential to promote insight to the developmental nature of EC.     

Motor Skills in Brazilian Children with Developmental Coordination Disorder versus Children with Motor Typical Development

The aims of the study were to compare the performance of children with probable developmental coordination disorder (DCD) and motor typically developing peers on items from the Assessment of Motor Coordination and Dexterity (AMCD), to determine whether age, gender and type of school had significant impact on the scores of the AMCD items, to estimate the frequency of DCD among Brazilian children ages 7 and 8 years and to investigate whether children with DCD exhibit more symptoms of attention deficit and hyperactivity disorder than children with motor typical development. A total of 793 children were screened by the Developmental Coordination Disorder Questionnaire – Brazilian version (DCDQ‐Brazil); 90 were identified as at risk for DCD; 91 matched controls were selected from the remaining participants. Children in both groups were evaluated with the AMCD, the Movement Assessment Battery for Children (MABC‐II) and Raven's coloured progressive matrices. Thirty‐four children were classified as probable DCD, as defined by a combination of the DCDQ‐Brazil and MABC‐II scores (fifth percentile). The final frequency of DCD among children ages 7 and 8 years was 4.3%. There were significant differences between children with and without DCD on the majority of AMCD items, indicating its potential for identifying DCD in Brazilian children. The use of a motor test (MABC‐II) that is not validated for the Brazilian children is a limitation of the present study. Further studies should investigate whether the AMCD is useful for identifying DCD in other age groups and in children from different regions of Brazil. The application of the AMCD may potentially contribute in improving occupational therapy practice in Brazil and in identifying children that could benefit from occupational therapy services. Copyright © 2014 John Wiley & Sons, Ltd.     

Deficits in motor co-ordination and attention at 3 years of age predict motor deviations in 6.5-year-old children who needed neonatal intensive care

Background   A total of 189 children without major impairments who needed neonatal intensive care (NIC) were followed up at ages 3 and 6.5 years.
Aim   To determine the prevalence of different motor deviations at age 6.5 years and the co-occurrence of attention deficits; also, to analyse the predictive ability of motor co-ordination and attention assessments at age 3 years for motor deviations at 6.5 years.
Method   A combined assessment of motor performance and behaviour (CAMPB) was used at the 3-year examination. The Test of Motor Impairment (TOMI) and the Motor-Perceptual Development (MPU) were used together with the criteria of the diagnostic and statistical manual of mental disorders (DSM-IV-TR) to define motor deviations.
Results   At 6.5 years 64% of the children showed a motor deviation either as a delay according to MPU, a problem according to TOMI or Developmental Coordination Disorder (DCD) according to DSM-IV-TR. Higher proportions of children with attention deficit (50%) were found in the DCD group. The predictive ability of CAMPB was analysed in two ways: when all children with either a co-ordination or attention deficit, or both, at 3 years were considered to be at risk for motor deviations at 6.5 years, the sensitivity reached 78% and the specificity was 42%. But when only the 3 year olds with a combined deficit were considered to be at risk, the sensitivity was 37% and the specificity 89%; however, a positive predictive value of 86% was reached.
Conclusion   At 6.5 years of age a majority of NIC children with no major impairments showed motor deviations. To fulfil the DCD criteria in DSM-IV-TR, a strict definition of motor deviations is recommended. Attention deficits are more prevalent among children with DCD. Deficits in motor co-ordination and/or attention in 3-year-old children are strong predictors of motor deviations and, especially, of DCD at 6.5 years of age.     

Searching for cognitively optimal challenge point in physical activity for children with typical and atypical motor development

Statement of problemGrowing evidence testifies that different types of physical activity (PA) interventions promote cognitive development, but the specific impact of the cognitive demands inherent in PA still remains underconsidered. This study investigated whether (1) increasing the cognitive demands of PA positively impacts children's executive function and (2) this ‘enrichment’ also matches the ability/skill level of children with Developmental Coordination Disorder (DCD).MethodsTwo hundred and fifty children aged 5–10 years participated in different physical education interventions, lasting six months, with or without special focus on cognitively demanding PA. Before and after the intervention, children's executive function was tested with the attention and planning subscales of the Cognitive Assessment System and their motor developmental level classified as typical, borderline, or DCD according to their performance evaluated by the Movement Assessment Battery for Children.ResultsAmong indices of executive function, those of Attention showed a differential effect of PA type as a function of children's motor developmental level: typically developing children gained greatest attentional benefit from PA with additional cognitive demands, while children with coordinative problems/impairment from the PA program without cognitive enrichment. Changes from DCD to borderline or normal developmental status did not differ in frequency as a function of intervention type.ConclusionsResults showed that cognitively more or less challenging PA programs are differently efficacious for promoting attention development and highlight the need to find and continuously reset the degree of task complexity in PA to match the optimal challenge point of normal and special children populations.