Cognitive and neuroimaging findings in developmental coordination disorder: new insights from a systematic review of recent research

Gaze training supports self-organization of movement coordination in children with developmental coordination disorder

Children with developmental coordination disorder (DCD) struggle with the acquisition of coordinated motor skills. This paper adopts a dynamical systems perspective to assess how individual coordination solutions might emerge following an intervention that trained accurate gaze control in a throw and catch task. Kinematic data were collected from six upper body sensors from twenty-one children with DCD, using a 3D motion analysis system, before and after a 4-week training intervention. Covariance matrices between kinematic measures were computed and distances between pairs of covariance matrices calculated using Riemannian geometry. Multidimensional scaling was then used to analyse differences between coordination patterns. The gaze trained group revealed significantly higher total coordination (sum of all the pairwise covariances) following training than a technique-trained control group. While the increase in total coordination also significantly predicted improvement in task performance, the distinct post-intervention coordination patterns for the gaze trained group were not consistent. Additionally, the gaze trained group revealed individual coordination patterns for successful catch attempts that were different from all the coordination patterns before training, whereas the control group did not. Taken together, the results of this interdisciplinary study illustrate how gaze training may encourage the emergence of coordination via self-organization in children with DCD.

Wearable-based electronics to objectively support diagnosis of motor impairments in school-aged children

Developmental coordination disorder (DCD) and attention-deficit hyperactivity disorder (ADHD) are neuro-developmental disorders, starting in childhood, which can affect the planning of movements and the coordination. We investigated how and in which measure a system based on wearable inertial measurement units (IMUs) can provide an objective support to the diagnosis of motor impairments in school-aged children. The IMUs measured linear and rotational movements of 37 schoolchildren, 7-10yo, 17 patients and 20 control subjects, during the execution of motor exercises, performed under medical and psychiatric supervision, to assess different aspects of the motor coordination. The measured motor parameters showed a high degree of significance in discriminating the ADHD/DCD patients from the healthy subjects, pointing out which motor tasks are worth focusing on. So, medical doctors have a novel key lecture to state a diagnosis, gaining in objectivity with respect to the standard procedures which mainly involve subjective human judgment. Differently to other works, we propose a novel approach in terms of number of used IMUs and of performed motor tasks. Moreover, we demonstrate the meaningful parameters to be considered as more discriminant in supporting the medical diagnosis.

Motor tests for primary school aged children: A systematic review

Motor testing in education has gained in relevance in light of recent developments in educational systems (Köller & Baumert, 2012). The purpose of this systematic review was to identify studies using motor tests in primary school children aged 4 to 12 years and to synthetize information about the quality and application of the test instruments used. A systematic review of 910 records identified by a search of nine databases yielded 144 papers reporting motor testing in primary school age children, including 25 articles reporting on the quality of 20 test instruments. In the selected articles, tests grounded on the constructs of "motor abilities" and/or "motor skills" are the most frequent and are mostly used for monitoring purposes or for impact research. Tests based on the construct "motor competencies" have become popular only recently, being relevant for educational motor testing due to their curricular validity. The test instruments have been investigated towards their validity and reliability to different extents. However, for several test instruments factorial validity has not been established and more validation studies are needed to improve their psychometric quality especially if used in educational contexts.

Developmental Coordination Disorder in Chinese Children Is Correlated With Cognitive Deficits

Cognitive deficits have been commonly observed in children with developmental coordination disorder (DCD), including memory, attention, and executive function difficulties. The present study evaluates the specific cognitive deficits in Chinese children with DCD, through a number of tests. A total of 401 children aged 7 to 10 years old from primary schools in Guangdong Province, China, participated in this study. Using the guidelines of the Movement Assessment Battery for Children ("Movement ABC-2"), a measurement tool of motor function ability, the children were divided into a DCD group, a group identified as being at risk of DCD, and a normal control group. The results of our analysis revealed that children's overall motor abilities could predict their overall cognitive ability, reaction time, memory, and attention. The performance of the DCD children was worse than that of the other two groups in terms of reaction time. The DCD group also returned lower scores for executive function than the normal control group did. A regression analysis showed that the cognitive deficits in children with DCD center mainly on poor executive function rather than attention and memory issues. These findings provide preliminary results regarding the cognitive deficits in Chinese children with DCD and have potential applications for the diagnosis and treatment of the disorder.

White matter organization in developmental coordination disorder: A pilot study exploring the added value of constrained spherical deconvolution

Previous studies of white matter organization in sensorimotor tracts in developmental coordination disorder (DCD) have adopted diffusion tensor imaging (DTI), a method unable to reconcile pathways with ‘crossing fibres’. In response to limitations of the commonly adopted DTI approach, the present study employed a framework that can reconcile the ‘crossing fibre’ problem (i.e., constrained spherical deconvolution- CSD) to characterize white matter tissue organization of sensorimotor tracts in young adults with DCD. Participants were 19 healthy adults aged 18–46: 7 met diagnostic criteria for DCD (4 females) and 12 were controls (3 females). All underwent high angular diffusion MRI. After preprocessing, the left and right corticospinal tracts (CST) and superior longitudinal fasciculi (SLF) were delineated and all tracts were then generated using both CSD and DTI tractography respectively. Based on the CSD model, individuals with DCD demonstrated significantly decreased mean apparent fibre density (AFD) in the left SLF relative to controls (with large effect size, Cohen's d = 1.32) and a trend for decreased tract volume of the right SLF (with medium-large effect size, Cohen's d = 0.73). No differences in SLF microstructure were found between groups using DTI, nor were differences in CST microstructure observed across groups regardless of hemisphere or diffusion model. Our data are consistent with the view that motor impairment characteristic of DCD may be subserved by white matter abnormalities in sensorimotor tracts, specifically the left and right SLF. Our data further highlight the benefits of higher order diffusion MRI (e.g. CSD) relative to DTI for clarifying earlier inconsistencies in reports speaking to white matter organization in DCD, and its contribution to poor motor skill in DCD.

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All previous diffusion studies of white matter in DCD have employed a tensor model

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We employed a non-tensor model to characterize microstructure in adults with DCD

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The non-tensor model showed atypical white matter organization in the SLF in DCD

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The tensor model failed to detect microstructural group differences for any tract

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Motor impairment characteristic of DCD may be subserved by white matter abnormalities

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We need to move beyond the tensor model in characterizing white matter in DCD

Empathy, social relationship and co-occurrence in young adults with DCD

Empathy is defined as an emotional or cognitive response to another's emotional state. It is considered essential for navigating meaningful social interactions and is closely linked to prosocial behavior. Developmental coordination disorder (DCD) is characterized by an impairment of motor coordination that has a marked impact on both academic and day-to-day living activities. Children and adolescents with DCD have been shown to have less developed social support and friendships. The research linking empathy and DCD is scarce. The aims of this study are to gain an understanding of the relationship between DCD and empathy in young adults with DCD only, and with DCD coupled with other neurodevelopmental disorders, in comparison with typically developing adults.

METHODS

The study included 212 young adults aged 18-40 years. The subjects in this study were from mainstream populations in the UK. The study groups included: (a) "DCD only" with 42 individuals; (b) "DCD + ASD" with 21 individuals; (c) "DCD + ADHD" with 45 individuals; (d) "DCD + ASD + ADHD" with 29 individuals; and (e) the control group of 75 individuals.

RESULTS

ANOVA on the Empathy Questionnaire (EQ) showed a statistically significant difference between groups (F [4,257] = 35.63; p < 0.001; η_p² = 0.409). No significant differences were found between the DCD-only and the control. MANOVA was performed to assess differences in the Socialising and Friendship Questionnaire (SAF-Q) scores. The results showed a statistically significant difference between groups (F [8,257] = 9.98; p < 0.001; η = 0.162). Pearson correlation coefficients were performed, revealing significant high correlations between the EQ and the two parts of the SAF-Q ("past" and "currently").

CONCLUSION

The results of this study indicate that social difficulties in the DCD-only group are not due to lack of empathy, but may be driven by an accumulation of external factors. In this study we also concluded that DCD does not appear to be the factor that reduces the ability to empathize, but rather the presence of ADHD and/or ASD.

Auditory processing and neuropsychological profiles of children with functional hearing loss

OBJECTIVES

This paper compares structured history, auditory processing abilities and neuropsychological findings of children with functional hearing loss (FHL) to those with suspected auditory processing disorder without FHL (control). The main aim was to evaluate the value of a holistic assessment protocol for FHL used in a routine pediatric audiology clinic. The protocol incorporated a commercially available test battery for auditory processing disorder (APD), non-verbal intelligence (NVIQ) and tools to screen for common co-existing neurodevelopmental conditions such as attention deficit hyperactivity disorder (ADHD), language impairment (LI) and developmental coordination disorder (DCD). The outcome of such holistic assessment was expected to help in understanding the nature of FHL and to provide individualized support to mitigate their difficulties.

METHODS

This retrospective study compared two groups, 40 children (M = 17, F = 23) in each group between seven and sixteen years of age, one group with a history of FHL and the other with suspected APD without FHL (control). The groups were matched against age, gender, hand use, diagnosis of APD or non-APD (31 with APD and 9 without APD in each group) and non-verbal intelligence. All the children were healthy English speaking children attending mainstream schools with no middle or inner ear abnormalities. Structured history was obtained from parents regarding different nonacademic and academic concerns. The SCAN-3:C and SCAN-3:A test batteries were used to assess auditory processing abilities; Lucid Ability test for NVIQ; Children's Communication Checklist-2 (CCC-2) for language ability; Swanson Nolan and Pelham-IV Rating Scale (SNAP-IV) for ADHD; and the manual dexterity components of the Movement Assessment Battery for Children-2 (MABC-2) as a screening tool for DCD.

RESULTS

About 60% of children in both the groups had concerns regarding listening in noisy background. In the history, poor attention was reported in 45% of children in the FHL group compared to 82.5% in the control group (p < 0.01). Hyperacusis was present in 35% of children in the FHL group and in 62% of children in the control group (p < 0.05). Concerns about overall academic abilities were present in 59% of children in the FHL group and 75% of the controls (p > 0.05). Only 15% of children in the FHL group had concerns with numeracy skills in contrast to 41% of the controls (p < 0.05). Significantly fewer (p < 0.01) children in the FHL group (41%) received additional support at school than the controls (75%). Fewer children performed poorly in Filtered Words (FW) test of the SCAN-3 batteries, 30% in the FHL group and 17.5% in the control group, in contrast to Auditory Figure Ground 0 (AFG0), 85% in FHL and 80% in the control group. The number of children performing poorly in AFG0 was significantly higher compared to all the other SCAN-3 tests in FHL (P < 0.05), in contrast to FW and Competing Sentences (CS) only in the control group (p < 0.05). The control group had higher prevalence of atypical ear advantage (AEA) in left directed Competing Words (CW) (32.5%) and Time Compressed Sentences (TCS) (32.5%) compared to FW (7.5%). In contrast, FHL group had higher prevalence of AEA in AFG0 (48.7%) compared to CS (21%). High proportions of children in both the groups had LI (80% in FHL and 82.5% in the control group), with significantly lower (p < 0.05) levels of ADHD symptoms in the FHL group (39.5%) compared to the control group (72.5%). Impaired manual dexterity was present in 30.7% of children in FHL group and 47.5% in the controls.

CONCLUSIONS

The prevalences of APD and language impairment are high compared to ADHD symptoms in children with FHL, and holistic assessment is recommended. Despite some similarities in the auditory and neuropsychological profiles between children with FHL and those with suspected APD without FHL some differences were noted. The results suggest that children with FHL have genuine difficulties that need to be identified and addressed. Future research is required to identify the neural pathways which could explain the similarities and dissimilarities between the two groups.

Brain network connectivity associated with anticipatory postural control in children and adults

Internal models provide a coherent framework for understanding motor behavior. Examples for the use of internal models include anticipatory postural adjustments (APAs), where the individual anticipates and cancels out the destabilizing effect of movement on body posture. Yet little is known about the functional changes in the brain supporting the development of APAs. Here, we addressed this issue by relating individual differences in APAs as assessed during bimanual load lifting to interindividual variation in brain network interactions at rest. We showed that the strength of the connectivity between three main canonical brain networks, namely the cingulo-opercular, the fronto-parietal and the somatosensory-motor networks, is an index of the ability to implement APAs from late childhood (9- to 11-year-old children). We also found an effect of age on the relationship between APAs and coupling strength between these networks, consistent with the notion that APAs are near but not yet fully mature in children. We discuss the implications of these findings for our understanding of learning disorders with impairment in predictive motor control.

Resting-State Functional MRI: Everything That Nonexperts Have Always Wanted to Know

Resting-state fMRI was first described by Biswal et al in 1995 and has since then been widely used in both healthy subjects and patients with various neurologic, neurosurgical, and psychiatric disorders. As opposed to paradigm- or task-based functional MR imaging, resting-state fMRI does not require subjects to perform any specific task. The low-frequency oscillations of the resting-state fMRI signal have been shown to relate to the spontaneous neural activity. There are many ways to analyze resting-state fMRI data. In this review article, we will briefly describe a few of these and highlight the advantages and limitations of each. This description is to facilitate the adoption and use of resting-state fMRI in the clinical setting, helping neuroradiologists become familiar with these techniques and applying them for the care of patients with neurologic and psychiatric diseases.

Investigating motor planning in children with DCD: Evidence from simple and complex grip-selection tasks

Several studies suggest that children with Developmental Coordination Disorder (DCD) may be able to plan simple movements as well as their peers, but experience increasing difficulties as the movements become complex. The present study aimed to clarify the nature of motor planning in DCD, including a putative deficit, by being the first to investigate motor planning using converging measures of simple and complex motor planning in a single sample of children with DCD. Boys aged between 8 and 12 years with (n = 10) and without DCD (n = 17) completed three commonly used 'simple' (bar grasping, sword, and bar transport tasks) measures and one 'complex' (octagon task) measure of end-state-comfort (ESC), a classic measurement of motor planning ability. To achieve ESC when manipulating an object, a person may choose to start with an uncomfortable grip in order to end the movement in a comfortable position. Results indicate that the participants with DCD planned for ESC as efficiently as their peers when performing the 'simple' measures of ESC but were significantly less likely to end their performances in ESC than those without DCD for the more 'complex' octagon task. Taken together, our data suggest that school-aged children with DCD may be able to plan simple movements as efficiently as their peers, but have more difficulty doing so for multi-movement or complex sequences. Based on the assumption that the efficiency of such motor planning is dependent on the integrity of internal modelling systems, we argue that our study provides indirect support for the internal modelling deficit hypothesis.

Variability in coordination patterns in children with developmental coordination disorder (DCD)

High motor variability is an often-found characteristic of Developmental Coordination Disorder (DCD). Still, the role of high motor variability in DCD needs further examination. This study focused on variability in coordination patterns, which is essential considering that DCD is a coordination disorder. We examined variability in coordination patterns of the arm over repetitions of trials in goal-directed reaching movements. This variability was partitioned into variability that does not affect the index fingertip position (V_ucm) and variability that does affect the index fingertip position (V_ort). This study aimed to increase the understanding of motor variability in DCD by comparing V_ucm and V_ort between children with DCD and typically developing (TD) children in a goal-directed reaching task. Twenty-two children (eleven with DCD) ages 6-11 performed 30 reaching movements. The Uncontrolled Manifold method was used to quantify V_ucm and V_ort. Results showed that children with DCD had more V_ucm than TD children while V_ort was similar between groups, showing that coordination patterns in children with DCD are more variable, but interestingly, this higher variability does not affect performance. This study indicates that high motor variability in DCD is not necessarily negative. Possible roles of motor variability in DCD are discussed.

Is auditory perceptual timing a core deficit of developmental coordination disorder?

Time is an essential dimension for perceiving and processing auditory events, and for planning and producing motor behaviors. Developmental coordination disorder (DCD) is a neurodevelopmental disorder affecting 5-6% of children that is characterized by deficits in motor skills. Studies show that children with DCD have motor timing and sensorimotor timing deficits. We suggest that auditory perceptual timing deficits may also be core characteristics of DCD. This idea is consistent with evidence from several domains, (1) motor-related brain regions are often involved in auditory timing process; (2) DCD has high comorbidity with dyslexia and attention deficit hyperactivity, which are known to be associated with auditory timing deficits; (3) a few studies report deficits in auditory-motor timing among children with DCD; and (4) our preliminary behavioral and neuroimaging results show that children with DCD at age 6 and 7 have deficits in auditory time discrimination compared to typically developing children. We propose directions for investigating auditory perceptual timing processing in DCD that use various behavioral and neuroimaging approaches. From a clinical perspective, research findings can potentially benefit our understanding of the etiology of DCD, identify early biomarkers of DCD, and can be used to develop evidence-based interventions for DCD involving auditory-motor training.

Feedforward motor control in developmental dyslexia and developmental coordination disorder: Does comorbidity matter?

BACKGROUND AND AIM

Feedforward and online controls are two facets of predictive motor control from internal models, which is suspected to be impaired in learning disorders. We examined whether the feedforward component is affected in children (8-12 years) with developmental dyslexia (DD) and/or with developmental coordination disorder (DCD) compared to typically developing (TD) children.

METHODS

Children underwent a bimanual unloading paradigm during which a load supported to one arm, the postural arm, was either unexpectedly unloaded by a computer or voluntary unloaded by the subject with the other arm.

RESULTS

All children showed a better stabilization (lower flexion) of the postural arm and an earlier inhibition of the arm flexors during voluntary unloading, indicating anticipation of unloading. Between-group comparisons of kinematics and electromyographic activity of the postural arm revealed that the difference during voluntary unloading was between DD-DCD children and the other groups, with the former showing a delayed inhibition of the flexor muscles.

CONCLUSION

Deficit of the feedforward component of motor control may particularly apply to comorbid subtypes, here the DD-DCD subtype. The development of a comprehensive framework for motor performance deficits in children with learning disorders will be achieved only by dissociating key components of motor prediction and focusing on subtypes and comorbidities.

Reactive balance performance and neuromuscular and cognitive responses to unpredictable balance perturbations in children with developmental coordination disorder

Developmental coordination disorder (DCD) is a common motor disorder affecting balance performance. However, few studies have investigated reactive balance performance and the underlying mechanisms in children with DCD. This study aimed to compare the reactive balance performance, lower limb muscle reflex contraction latency and attention level in response to unpredictable balance perturbations between 100 typically developing children and 120 children with DCD (with and without comorbid autism spectrum disorder) aged 6-9 years. Reactive balance performance was evaluated using a motor control test (MCT) conducted on a computerized dynamic posturography machine. The lower limb postural muscle responses and attention level before, during and after a MCT were measured using surface electromyography and electroencephalography, respectively. The results revealed that relative to typically developing children, those with DCD had a significantly longer MCT latency score in the backward platform translation condition (p = 0.048) but a significantly shorter latency score in the forward platform translation condition (p = 0.024). The MCT composite latency scores and the corresponding lower limb muscle onset latencies were similar between the groups. Children with DCD also demonstrated a lower attention level during and after sudden backward (p = 0.042) and forward (p = 0.031) platform translations, compared to typically developing children. Children with DCD were less attentive in response to postural threats, and their balance responses were direction-specific. Balance training for children with DCD might require an additional emphasis on sudden posterior-to-anterior balance perturbations, as well as on problems with inattention.

A research framework to isolate visuospatial from childhood motor coordination phenotypes

Clinicians acknowledge the presence of developmental cognitive phenotypes mainly characterized by a specific visuospatial impairment in presence of intact verbal functioning (usually referred as Nonverbal Learning Disability: NLD) since many decades, without providing sufficient empirical evidence supporting their nosological validity and inclusion in current diagnostic manuals. This contribution suggests that the goal of including NLD in future diagnostic manuals could be achieved only be the demonstration of the validity of this hypothesized clinical category. Considering the blind spot of empirical literature represented by the differential diagnosis of NLD, this issue should the primary focus of empirical research supported by a renewed interest on NLD. Both neurophysiological and clinical evidence suggest that the differential diagnosis and the related empirical comparison should be primarily settled with Developmental Coordination Disorder, looking for the possible identification of children presenting a visuospatial impairment in absence of severe motor coordination impairment. In conclusion, further studies are needed to support the validity of NLD as valid diagnostic category to be included in future revisions of diagnostic manuals.

Linear and Nonlinear Analyses of the Cardiac Autonomic Control in Children With Developmental Coordination Disorder: A Case-Control Study

Children with Developmental Coordination Disorder (DCD) and children at risk for DCD (r-DCD) present motor impairments interfering in their school, leisure and daily activities. In addition, these children may have abnormalities in their cardiac autonomic control, which together with their motor impairments, restrict their health and functionality. Therefore, this study aimed to assess the cardiac autonomic control, by linear and nonlinear analysis, at supine and during an orthostatic stimulus in DCD, r-DCD and typically developed children. Thirteen DCD children (11 boys and 2 girls, aged 8.08 ± 0.79 years), 19 children at risk for DCD (13 boys and 6 girls, aged 8.10 ± 0.96 years) and 18 typically developed children, who constituted the control group (CG) (10 boys and 8 girls, aged 8.50 ± 0.96 years) underwent a heart rate variability (HRV) examination. R-R intervals were recorded in order to assess the cardiac autonomic control using a validated HR monitor. HRV was analyzed by linear and nonlinear methods and compared between r-DCD, DCD, and CG. The DCD group presented blunted cardiac autonomic adjustment to the orthostatic stimulus, which was not observed in r-DCD and CG. Regarding nonlinear analysis of HRV, the DCD group presented lower parasympathetic modulation in the supine position compared to the r-DCD and CG groups. In the within group analysis, only the DCD group did not increase HR from supine to standing posture. Symbolic analysis revealed a significant decrease in 2LV (p < 0.0001) and 2UV (p < 0.0001) indices from supine to orthostatic posture only in the CG. In conclusion, r-DCD and DCD children present cardiac autonomic dysfunction characterized by higher sympathetic, lower parasympathetic and lower complexity of cardiac autonomic control in the supine position, as well as a blunted autonomic adjustment to the orthostatic stimulus. Therefore, cardiovascular health improvement should be part of DCD children's management, even in cases of less severe motor impairment.

Interhemispheric Cortical Inhibition Is Reduced in Young Adults With Developmental Coordination Disorder

Introduction

While the etiology of developmental coordination disorder (DCD) is yet to be established, brain-behavior modeling provides a cogent argument that neuropathology may subserve the motor difficulties typical of DCD. We argue that a number of the core behavioral features of the DCD profile (such as poor surround inhibition, compromised motor inhibition, and the presence of mirror movements) are consistent with difficulties regulating inhibition within the primary motor cortex (M1). This study aimed to be the first account of the integrity of cortical inhibition in motor cortices in DCD.

Method

The sample consisted of eight adults with DCD aged (18–30 years) and 10 aged matched neurotypical controls. Participants received a common battery of single and paired-pulse transcranial magnetic stimulation from which a series of neurophysiological measures classically used to measure intra- [e.g., short-interval cortical inhibition (SICI), long-interval cortical inhibition (LICI), and cortical silent period] and inter hemispheric [e.g., ipsilateral silent period (ISP)] cortical inhibition of the M1 at rest were recorded.

Results

While no group differences were observed for any measure of intrahemispheric cortical inhibition, individuals with DCD demonstrated significantly reduced interhemispheric cortical inhibition relative to controls, shown by consistently lower ISP_ratios.

Conclusion

Our findings are consistent with the view that regulation of cortical inhibition of M1 activity may be atypical in individuals with DCD, indicating differential GABAergic operation. This effect, however, appears to be select to cortical inhibition. Importantly, our data support the notion that reduced interhemispheric M1 cortical inhibition may at least partly explain commonly reported difficulties with bimanual motor control in DCD. The neurochemical implications and limitations of this evidence will be discussed.

Evaluating the evidence for motor-based interventions in developmental coordination disorder: A systematic review and meta-analysis

BACKGROUND

As part of the process of creating an update of the clinical practice guidelines for developmental coordination disorder (DCD) (Blank, Smits-Engelsman, Polatajko, & Wilson, 2012), a systematic review of intervention studies, published since the last guidelines statement was conducted.

AIM

The aim of this study was to 1) systematically review the evidence published from January 2012 to February 2017 regarding the effectiveness of motor based interventions in individuals with DCD, 2) quantify treatment effects using a meta-analysis, 3) examine the available information on different aspects of delivery including use of group intervention, duration and frequency of therapy, and 4) identify gaps in the literature and make recommendations for future intervention research.

METHOD

An electronic search of 5 databases (PubMed, Embase, Pedro, Scopus and Cochrane) was conducted for studies that evaluated motor-based interventions to improve performance for individuals with DCD.

RESULTS

Thirty studies covering 25 datasets were included, 19 of which provided outcomes on standardized measures of motor performance. The overall effect size (Cohen's d) across intervention studies was large (1.06), but the range was wide: for 11 interventions, the observed effect was large (>0.80), in eight studies moderate (>0.50), and in five it was small or negligible (<0.50). Positive benefits were evident for activity-oriented approaches, body function-oriented combined with activities, active video games, and small group programs.

CONCLUSION

Results showed that activity-oriented and body function oriented interventions can have a positive effect on motor function and skills. However, given the varied methodological quality and the large confidence intervals of some studies, the results should be interpreted with caution.

Executive functions in children with developmental coordination disorder: a 2-year follow-up study

AIM

Executive function impairments have been identified in children with poor motor skills, with and without a diagnosis of developmental coordination disorder (DCD). However, most studies are cross-sectional. This study investigates the development of executive function in children with poor motor skills over 2 years.

METHOD

Children aged 7 to 11 years (n=51) were assessed twice, 2 years apart, on verbal and nonverbal measures of executive functions: executive-loaded working memory (ELWM); fluency; response inhibition; planning; and cognitive flexibility. Typically developing children (n=17) were compared with those with a clinical diagnosis of DCD (n=17) and those with identified motor difficulties (n=17) but no formal diagnosis of DCD.

RESULTS

Developmental gains in executive function were similar between groups, although a gap between children with poor motor skills and typically developing children on nonverbal executive functions persisted. Specifically, children with DCD performed significantly more poorly than typically developing children on all nonverbal executive function tasks and verbal fluency tasks at both time points; and children with motor difficulties but no diagnosis of DCD showed persistent executive function problems in nonverbal tasks of ELWM and fluency.

INTERPRETATION

Children with DCD and motor difficulties demonstrated executive function difficulties over 2 years, which may affect activities of daily living and academic achievement, in addition to their motor deficit.

WHAT THIS PAPER ADDS

Executive function difficulties in children with poor motor skills persist throughout middle childhood. Children with motor difficulties, without a developmental coordination disorder (DCD) diagnosis, demonstrate less pervasive executive function difficulties than those with DCD. Executive function problems in the groups with motor difficulties and DCD affect mostly nonverbal domains. All groups showed similar developmental gains in executive function.

Understanding Organisational Ability and Self-Regulation in Children with Developmental Coordination Disorder

PURPOSE OF THE REVIEW

This paper examines physical and emotional coherence in young people with developmental coordination disorder (DCD). Specifically, the transactional relationship between motor and non-motor/executive dysfunction in children with DCD and its impact on psychosocial functioning is explored.

RECENT FINDINGS

This paper integrates the subjective reported experiences of young people with DCD with objective measurements and findings from neuroimaging studies.

SUMMARY

Consideration of the transactional relationship between the person, the activity and the environment, whether these factors be physical, social, attitudinal or virtual, will be fundamental to our understanding of the mechanisms underpinning organisational and emotional issues presenting in DCD. Integrating the experiences of young people with research evidence will be essential to improve outcomes for young people with DCD in clinical practice.

A Perception-Action Approach to Understanding Typical and Atypical Motor Development

In this chapter, we ask two questions. First, can the study of the perception-action system across time offer a useful model for understanding motor development? Second, can the study of the perception-action system in children with developmental coordination disorder (DCD) inform our understanding of atypical as well as typical motor development? We begin by describing the dynamical systems perspective and a control-theoretic approach that together provide the conceptual framework for our paradigms, methodology, and interpretation of our experiments. Our experimental strategy has been to perturb one or more sensory systems and observe the effect on the motor system. The majority of the chapter explains how we employed two principal perturbation strategies: (1) removing or adding a static source of sensory information believed to be salient to the task at hand and (2) enhancing a dynamic source of sensory information either implicitly or explicitly. These strategies were employed in three different action systems: posture; rhythmic interlimb coordination, and goal-directed reaching and drawing. After synthesizing our findings, we conclude by addressing the original questions and offering future directions. In brief, we consider that perception-action coupling is an underlying mechanism/foundation/constraint of motor development in the sense that the ongoing processing of sensations and the planning and execution of movements are how the brain produces goal-directed movements. Therefore, a better understanding of how this coupling changes or adapts over time has much to offer as to how motor behavior develops across the lifespan, both typically and atypically.