DCD and ADHD: a genetic study of their shared aetiology

Locomotor-cognitive dual-tasking in children with developmental coordination disorder

Introduction

Children with Developmental Coordination Disorder (DCD) demonstrate deficits in predictive motor control and aspects of cognitive control compared with their typically developing (TD) peers. Adjustment to dynamic environments depends on both aspects of control and the deficits for children with DCD may constrain their ability to perform daily actions that involve dual-tasking. Under the assumption that motor-cognitive integration is compromised in children with DCD, we examined proportional dual-task costs using a novel locomotor-cognitive dual-task paradigm that enlisted augmented reality. We expect proportional dual-task performance costs to be greater for children with DCD compared to their TD peers.

Methods

Participants were 34 children aged 6-12 years (16 TD, 18 DCD) who walked along a straight 12 m path under single- and dual-task conditions, the cognitive task being visual discrimination under simple or complex stimulus conditions presented via augmented reality. Dual-task performance was measured in two ways: first, proportional dual-task costs (pDTC) were computed for cognitive and gait outcomes and, second, within-trial costs (p-WTC) were measured as the difference on gait outcomes between pre- and post-stimulus presentation.

Results

On measures of pDTC, TD children increased their double-limb support time when walking in response to a dual-task, while the children with DCD increased their locomotor velocity. On p-WTC, both groups increased their gait variability (step length and step width) when walking in response to a dual-task, of which the TD group had a larger proportional change than the DCD group. Greater pDTCs on motor rather than cognitive outcomes were consistent across groups and method of dual-task performance measurement.

Discussion

Contrary to predictions, our results failed to support dramatic differences in locomotor-cognitive dual-task performance between children with DCD and TD, with both groups tending to priorities the cognitive over the motor task. Inclusion of a within-trial calculation of dual-task interference revealed an expectancy effect for both groups in relation to an impending visual stimulus. It is recommended that dual-task paradigms in the future continue to use augmented reality to present the cognitive task and consider motor tasks of sufficient complexity to probe the limits of performance in children with DCD.

The ability to maintain rhythm is predictive of ADHD diagnosis and profile

Attention deficit hyperactivity disorder (ADHD) is the most prevalent neuropsychiatric disorder in the world. Currently, the diagnosis is based mainly on interviews, resulting in uncertainties in the clinical assessment. While some neuropsychological tests are used, their specificity and selectivity are low, and more reliable biomarkers are desirable. Previous research indicates that ADHD is associated with morphological changes in the cerebellum, which is essential for motor ability and timing. Here, we compared 29 children diagnosed with ADHD to 96 age-matched controls on prism adaptation, eyeblink conditioning, and timed motor performance in a finger tapping task. Prism adaptation and timing precision in the finger tapping task, but not performance on eyeblink conditioning, differed between the ADHD and control groups, as well as between children with and without Deficits in Attention, Motor control, and Perception (DAMP) - a more severe form of ADHD. The results suggest finger tapping can be used as a cheap, objective, and unbiased biomarker to complement current diagnostic procedures.

Pathogenetic Insights into Developmental Coordination Disorder Reveal Substantial Overlap with Movement Disorders

Developmental Coordination Disorder (DCD) is a neurodevelopmental condition characterized by non-progressive central motor impairments. Mild movement disorder features have been observed in DCD. Until now, the etiology of DCD has been unclear. Recent studies suggested a genetic substrate in some patients with DCD, but comprehensive knowledge about associated genes and underlying pathogenetic mechanisms is still lacking. In this study, we first identified genes described in the literature in patients with a diagnosis of DCD according to the official diagnostic criteria. Second, we exposed the underlying pathogenetic mechanisms of DCD, by investigating tissue- and temporal gene expression patterns and brain-specific biological mechanisms. Third, we explored putative shared pathogenetic mechanisms between DCD and frequent movement disorders with a known genetic component, including ataxia, chorea, dystonia, and myoclonus. We identified 12 genes associated with DCD in the literature, which are ubiquitously expressed in the central nervous system throughout brain development. These genes are involved in cellular processes, neural signaling, and nervous system development. There was a remarkable overlap (62%) in pathogenetic mechanisms between DCD-associated genes and genes linked with movement disorders. Our findings suggest that some patients might have a genetic etiology of DCD, which could be considered part of a pathogenetic movement disorder spectrum.

Connectivity differences between inferior frontal gyrus and mentalizing network in autism as compared to developmental coordination disorder and non-autistic youth

Prior studies have compared neural connectivity during mentalizing tasks in autism (ASD) to non-autistic individuals and found reduced connectivity between the inferior frontal gyrus (IFG) and mentalizing regions. However, given that the IFG is involved in motor processing, and about 80% of autistic individuals have motor-related difficulties, it is necessary to explore if these differences are specific to ASD or instead similar across other developmental motor disorders, such as developmental coordination disorder (DCD). Participants (29 ASD, 20 DCD, 31 typically developing [TD]; ages 8-17) completed a mentalizing task in the fMRI scanner, where they were asked to think about why someone was performing an action. Results indicated that the ASD group, as compared to both TD and DCD groups, showed significant functional connectivity differences when mentalizing about other's actions. The left IFG seed revealed ASD connectivity differences with the: bilateral temporoparietal junction (TPJ), left insular cortex, and bilateral dorsolateral prefrontal cortex (DLPFC). Connectivity differences using the right IFG seed revealed ASD differences in the: left insula, and right DLPFC. These results indicate that connectivity differences between the IFG, mentalizing regions, emotion and motor processing regions are specific to ASD and not a result of potentially co-occurring motor differences.

Advances in Genetics and Epigenetics of Developmental Coordination Disorder in Children

Developmental coordination disorder (DCD) is a developmental disorder characterized by impaired motor coordination, often co-occurring with attention deficit disorder, autism spectrum disorders, and other psychological and behavioural conditions. The aetiology of DCD is believed to involve brain changes and environmental factors, with genetics also playing a role in its pathogenesis. Recent research has identified several candidate genes and genetic factors associated with motor impairment, including deletions, copy number variations, single nucleotide polymorphisms, and epigenetic modifications. This review provides an overview of the current knowledge in genetic research on DCD, highlighting the importance of continued research into the underlying genetic mechanisms. While evidence suggests a genetic contribution to DCD, the evidence is still in its early stages, and much of the current evidence is based on studies of co-occurring conditions. Further research to better understand the genetic basis of DCD could have important implications for diagnosis, treatment, and our understanding of the condition's aetiology.

Where Do Neurodevelopmental Disorders Go? Casting the Eye Away from Childhood towards Adulthood

Neurodevelopmental disorders (NDDs) encompass a group of complex conditions with onset during the early developmental period. Such disorders are frequently associated with a number of neuropsychiatric features, the most prevalent ones being autism spectrum disorder, attention-deficit/hyperactivity disorder, intellectual disability, communication and specific learning disorders, and motor disorders. These conditions are characterized by wide genetic and clinical variability, and although they were previously conceptualized as childhood-limited disorders, NDDs are progressively being recognized as persistent conditions with a potentially relevant impact on the quality of life and overall functioning during adult life. In addition, emerging evidence seems to point towards the hypothesis of a neurodevelopmental continuum, according to which NNDs could portray different time-dependent outcomes, depending on the severity of the altered brain development. Despite representing lifelong phenotypes, they are often not promptly identified and/or managed in adulthood. In this regard, specific guidelines on clinical and therapeutic approaches for these conditions have not yet been delineated. In this view, future research investigations should be encouraged to broaden available knowledge, characterize the clinical course of NDDs across an individual’s lifespan, and better understand the patterns of aging-related concerns in adults with an NDD diagnosis. Additionally, considering the difficulties many young adults encounter while transitioning from childhood to adult mental health services, new, specific programs should be developed and existing programs should be implemented to improve the transition process and for the management of NDDs in adulthood.

A meta-analysis of genetic effects associated with neurodevelopmental disorders and co-occurring conditions

A systematic understanding of the aetiology of neurodevelopmental disorders (NDDs) and their co-occurrence with other conditions during childhood and adolescence remains incomplete. In the current meta-analysis, we synthesized the literature on (1) the contribution of genetic and environmental factors to NDDs, (2) the genetic and environmental overlap between different NDDs, and (3) the co-occurrence between NDDs and disruptive, impulse control and conduct disorders (DICCs). Searches were conducted across three platforms: Web of Science, Ovid Medline and Ovid Embase. Studies were included only if 75% or more of the sample consisted of children and/or adolescents and the studies had measured the aetiology of NDDs and DICCs using single-generation family designs or genomic methods. Studies that had selected participants on the basis of unrelated diagnoses or injuries were excluded. We performed multilevel, random-effects meta-analyses on 296 independent studies, including over four million (partly overlapping) individuals. We further explored developmental trajectories and the moderating roles of gender, measurement, geography and ancestry. We found all NDDs to be substantially heritable (family-based heritability, 0.66 (s.e. = 0.03); SNP heritability, 0.19 (s.e. = 0.03)). Meta-analytic genetic correlations between NDDs were moderate (grand family-based genetic correlation, 0.36 (s.e. = 0.12); grand SNP-based genetic correlation, 0.39 (s.e. = 0.19)) but differed substantially between pairs of disorders. The genetic overlap between NDDs and DICCs was strong (grand family-based genetic correlation, 0.62 (s.e. = 0.20)). While our work provides evidence to inform and potentially guide clinical and educational diagnostic procedures and practice, it also highlights the imbalance in the research effort that has characterized developmental genetics research.

Handwriting Evaluation in School-Aged Children With Developmental Coordination Disorder: A Literature Review

Despite widespread computer use, legible handwriting remains an important common life skill that requires more attention from schools and health professionals. Importantly, instructors and parents typically attribute the difficulties to laziness or a lack of effort, causing the youngster anger and disappointment. Handwriting issues are a public health concern in terms of both prevalence and consequences. Writing is a tough and diverse activity that requires cognitive, perceptual-motor, mental, and emotional talents. It is largely a motor process involving an effective level of motor organization that results in exact movement synchronization. Handwriting problems have been connected to developmental disorders such as developmental coordination disorder. For the affected youngsters, forming letters takes more work, and the kid may forget what he or she planned to write. School children's primary handwriting issues include illegible writing, slow handwriting, and strained writing. Handwriting problems may lead to scholastic underachievement and low self-esteem. Because of this complication, some school-aged children develop handwriting difficulties, which cause psychological distress and learning impairments. In the treatment of children with bad handwriting, the therapeutic intervention has been demonstrated to be successful. We aimed to determine how efficient tools and scales are which assess handwriting in school-aged children having developmental coordination disorder. Keyword searches were conducted on Google Scholar and PubMed, yielding 45 results, eight of which met the inclusion requirements. We concluded that there are a lot of scales and tools to date but no scale focuses on the temporal and spatial parameters for handwriting evaluation.

Sensory Modulation in Children with Developmental Coordination Disorder Compared to Autism Spectrum Disorder and Typically Developing Children

Developmental Coordination Disorder (DCD) is one of the least studied and understood developmental disorders. One area that has been minimally investigated in DCD is potential issues with sensory modulation. Further, in other neurodevelopmental disorders (e.g., autism spectrum disorder (ASD)) sensory modulation is related to many other challenges (e.g., social issues, repetitive behaviors, anxiety); however, such potential relationships in children with DCD have been largely unexplored. The purpose of this study is to explore sensory modulation differences in DCD and to understand the relationships between sensory modulation and social emotional measures, behavior, and motor skills in DCD in comparison to ASD and typically developing (TD) peers. Participants (aged 8–17) and their caregivers (DCD, N = 26; ASD, N = 57; and TD, N = 53) completed behavioral and clinical measures. The results indicated that 31% of the DCD group showed sensory modulation difficulties, with the DCD group falling between the ASD and TD groups. In the DCD group, sensory modulation was significantly associated with anxiety, empathic concern, repetitive behaviors, and motor skills. Data are compared to patterns seen in ASD and TD groups and implications for interventions are discussed.

Effects of Comorbid Developmental Coordination Disorder and Symptoms of Attention Deficit Hyperactivity Disorder on Physical Activity in Children Aged 4-5 Years

Developmental coordination disorder (DCD) is often comorbid with attention-deficit/hyperactivity disorder (ADHD). While children with DCD engage in less moderate-to-vigorous physical activity (MVPA) compared to typically developing (TD) children, research pertaining to how ADHD affects this relationship is limited. We investigated the effect of ADHD on MVPA among children at risk for DCD (DCDr). 507 children aged 4-5 years (DCDr = 233, TD = 274) participated. Motor skills were assessed using the Movement Assessment Battery for Children-2nd edition (DCDr; ≤ 16th percentile), ADHD symptoms were assessed using the Child Behaviour Checklist, and Actigraph accelerometers measured MVPA over seven days. DCD did not negatively affect MVPA, however, after adjusting for ADHD symptoms, the effect of DCD became significant and was driven by symptoms of inattention. Symptoms of ADHD may be suppressing the negative effects of DCD on MVPA, highlighting the importance of assessing and controlling for ADHD symptoms in this population.

The adult developmental coordination disorders/dyspraxia checklist - German: adapted factor structure for the differentiation of DCD and ADHD

BACKGROUND

The Adult Dyspraxia/DCD Checklist (ADC) is the only existing self-report questionnaire to screen adults for potential Developmental Coordination Disorder (DCD). It was developed in English and Hebrew, however, its factor structure has not yet been assessed.

AIMS

The goals of the current study were to (1) develop and refine a German translation, (2) explore the emerging factors in a new and restructured ADC in German and apply this structure to an English ADC, and (3) explore its potential for distinguishing DCD versus ADHD.

METHOD

In a series of three studies, we assessed comprehensibility of the translation and revisions to the questionnaire. We further examined subscale structure in a sample of N = 148 individuals with DCD or ADHD and retested it in an English-speaking sample (N = 134).

RESULTS

Overall, we found decent reliability and construct validity for the German ADC. Three components emerged with themes of fine motor coordination, gross motor coordination, and executive functions which had strong psychometric properties in German and English.

CONCLUSIONS

The studies collectively highlight the German translation is effective and has strong potential to differentiate DCD and ADHD. Most notably, there are unique symptom profiles in motor and executive functioning difficulties in adults with DCD or ADHD. WHAT THIS PAPER ADDS?: The translation and preliminary validation of the German ADC in this study has the potential to screen for probable DCD in German-speaking adults for the first time. In addition, the new subscale structure can be generalized to the English version as well and allows for the potential assessment of several key symptomatic patterns in the realms of gross motor, fine motor, and executive functioning skills that differ between adults with DCD and ADHD. These differences were fairly consistent between English- and German-speaking samples, indicating potential for more widespread assessment and differentiation of DCD and ADHD.

Brain functional connectivity in children with developmental coordination disorder following rehabilitation intervention

BACKGROUND

Children with developmental coordination disorder (DCD) show improved motor function after Cognitive Orientation to Occupational Performance (CO-OP) intervention; however, the neural basis for these improvements is unknown.

METHODS

In this randomized waitlist-controlled trial, 78 children with DCD (with/without ADHD) were randomly assigned to either a treatment or waitlist group and underwent three resting-state MRI scans over six months. The treatment group received intervention between the first and second scan; the waitlist group received intervention between the second and third scan.

RESULTS

After CO-OP intervention, children with DCD [13 male, 8 female; mean (SD) age: 10.0 (1.7) years] showed increased functional connectivity between the default mode network and right anterior cingulate gyrus (p < 0.01). Additional gains were noted at follow-up three months after the intervention, with greater functional connectivity between the dorsal attention network and precentral gyrus (p < 0.02). However, children with DCD + ADHD [18 male, 1 female; mean (SD) age: 10.0 (1.14) years] did not show brain changes following CO-OP.

CONCLUSION

For children with DCD, increased functional connectivity in networks associated with self-, emotion-, and attention-regulation may underlie motor skill improvements observed after CO-OP intervention. Modifications to the CO-OP protocol may be required to induce similar brain changes in children with DCD + ADHD.

IMPACT

This study provides neuroscientific evidence for the Cognitive Orientation to Occupational Performance (CO-OP) approach as an effective rehabilitation intervention to induce brain and behavioral changes in children with DCD. While children with DCD ± ADHD showed improved motor function after CO-OP, only children with DCD showed brain changes after intervention. Children with DCD showed increased functional connectivity in networks associated with self-, emotion-, and attention-regulation after the intervention. Treatment modifications may be required to induce similar brain changes in children with DCD + ADHD. Pediatricians are encouraged to refer children with DCD  with and without ADHD for CO-OP intervention to improve their motor skills.

Participation According to Clinicians Working with Young Children with Developmental Disabilities: A Long Way to Go

Participation has become an important measure of outcome in child rehabilitation as young children with developmental disabilities are increasingly at risk of decreased participation. Therefore, this study garnered information on clinicians' perspectives regarding perceived facilitators and barriers when rendering participation-based interventions using a qualitative research design. Semi-structured interviews of clinicians (Ns = 12, 25-57 years) were conducted and evaluated via an inductive thematic analysis. Results denote that current mechanisms of providing participation-based interventions resembled traditionally focused interventions; thus, resulting in a knowledge-to-practice gap. Clinicians desired more opportunities to communicate with caregivers and to be able to influence the children' s natural environments. They also identified shortness of time, resources, and rigid health care regulations as barriers hampering the efficacy of participation-based services.

Genome-Wide Association Study of Motor Coordination

The ability to finely control our movement is key to achieving many of the educational milestones and life-skills we develop throughout our lives. Despite the centrality of coordination to early development, there is a vast gap in our understanding of the underlying biology. Like most complex traits, both genetics and environment influence motor coordination, however, the specific genes, early environmental risk factors and molecular pathways are unknown. Previous studies have shown that about 5% of school-age children experience unexplained difficulties with motor coordination. These children are said to have Developmental Coordination Disorder (DCD). For children with DCD, these motor coordination difficulties significantly impact their everyday life and learning. DCD is associated with poorer academic achievement, reduced quality of life, it can constrain career opportunities and increase the risk of mental health issues in adulthood. Despite the high prevalence of coordination difficulties, many children remain undiagnosed by healthcare professionals. Compounding under-diagnosis in the clinic, research into the etiology of DCD is severely underrepresented in the literature. Here we present the first genome-wide association study to examine the genetic basis of early motor coordination in the context of motor difficulties. Using data from the Avon Longitudinal Study of Parents and Children we generate a derived measure of motor coordination from four components of the Movement Assessment Battery for Children, providing an overall measure of coordination across the full range of ability. We perform the first genome-wide association analysis focused on motor coordination (N = 4542). No single nucleotide polymorphisms (SNPs) met the threshold for genome-wide significance, however, 59 SNPs showed suggestive associations. Three regions contained multiple suggestively associated SNPs, within five preliminary candidate genes: IQSEC1, LRCC1, SYNJ2B2, ADAM20, and ADAM21. Association to the gene IQSEC1 suggests a potential link to axon guidance and dendritic projection processes as a potential underlying mechanism of motor coordination difficulties. This represents an interesting potential mechanism, and whilst further validation is essential, it generates a direct window into the biology of motor coordination difficulties. This research has identified potential biological drivers of DCD, a first step towards understanding this common, yet neglected neurodevelopmental disorder.

White Matter Changes With Rehabilitation in Children With Developmental Coordination Disorder: A Randomized Controlled Trial

Background and Objectives: Children with developmental coordination disorder (DCD) have difficulty learning motor skills, which can affect their participation in activities of daily living and psychosocial well-being. Over 50% of children with DCD also have attention deficit hyperactivity disorder (ADHD), which further exacerbates their motor problems and impact on quality of life. A rehabilitation approach known as Cognitive Orientation to Occupational Performance uses problem-solving strategies to help children learn motor skills they wish to achieve. While this cognitive approach has been effective for children with DCD, few studies have examined the effectiveness of this approach for children with co-occurring ADHD. Further, the underlying mechanism and neural basis of this intervention are largely unknown.

Methods: In this randomized waitlist-controlled trial, we used MRI to examine white matter microstructure after intervention in 8–12-year-old children with DCD (n = 28) and with DCD and co-occurring ADHD (n = 25). Children in both groups were randomized to either a treatment group or waitlist group at their first MRI. The treatment group began the intervention after their MRI scan and returned for a post-treatment scan at 3 months, and follow-up scan at 6 months; the waitlist group waited 3 months before their second MRI, received the intervention, and then had a post-treatment scan. Each child received intervention once weekly for 10 weeks. Diffusion tensor imaging was used to acquire white matter diffusion parameters and was analyzed using tract-based spatial statistics (TBSS).

Results and Conclusion: Children with DCD showed significant improvement in white matter microstructure in the bilateral anterior thalamic radiation, bilateral sensorimotor tract, bilateral cingulum, fornix, splenium and body of corpus callosum, right inferior fronto-occipital fasciculus, and white matter pathways to bilateral inferior gyri, right middle frontal gyrus, frontal medial cortex, and left cuneus. We suggest that these rehabilitation-induced neural changes in children with DCD occurred in regions associated with attention, self-regulation, motor planning, and inter-hemispheric communication, which positively affected brain connectivity and motor function. In contrast, children with DCD and co-occurring ADHD did not show any brain changes following the intervention. Modifications to the treatment protocol might help address the attentional and self-regulatory needs of children with a dual diagnosis.

Clinical Trial Registration: ClinicalTrials.gov ID: NCT02597751.

Participation of young children with developmental disabilities: parental needs and strategies, a qualitative thematic analysis

OBJECTIVES

Participation refers to a person's involvement in activities and roles that provide interaction with others as well as engagement in family and community activities. Young children with developmental disabilities (DD) such as attention deficit hyperactive disorder, autism spectrum disorder and developmental coordination disorder are limited in their participation compared with their typically developing peers. This study aimed to obtain information regarding parental needs and strategies used to enable their child's participation.

DESIGN

A thematic inductive approach with in-depth interviews was used to explore parental experiences. Eleven women and two men, between 30 and 40 years of age, who had a child (4-9 years old) with a DD diagnosis based on Diagnostic and Statistical Manual of Mental Disorders criteria, participated in semistructured interviews.

RESULTS

Two central themes emerged: parental needs and parental strategies used to enable their child's participation. Parental needs were the following: increasing awareness, ameliorating parental burden, providing tailored interventions and supporting parents in finding suitable leisure activities. Parental strategies aimed at increasing their child's resiliency, attaining maximal fit between activity requirements and child capacity, and creating inclusive opportunities and awareness.

CONCLUSIONS

Understanding what families' needs are and how families use and integrate strategies within the context of their daily lives provides practitioners with insights needed to support families' resiliency in promoting their children's participation. The results have implications for professionals as this information can be used to inform, refine, or tailor participation-based and family-centred services.

Evoked Potentials Differentiate Developmental Coordination Disorder From Attention-Deficit/Hyperactivity Disorder in a Stop-Signal Task: A Pilot Study

Developmental Coordination Disorder and Attention-Deficit/Hyperactivity Disorder are unique neurodevelopmental disorders with overlaps in executive functions and motor control. The conditions co-occur in up to 50% of cases, raising questions of the pathological mechanisms of DCD versus ADHD. Few studies have examined these overlaps in adults with DCD and/or ADHD. Therefore, to provide insights about executive functions and motor control between adults with DCD, ADHD, both conditions (DCD + ADHD), or typically developed controls, this study used a stop-signal task and parallel EEG measurement. We assessed executive performance via go accuracy and go reaction time, as well as motor response inhibition via stop-signal reaction time. This was complemented with analysis of event-related potentials (ERPs). Based on existing investigations of adults with DCD or ADHD, we expected (1) groups would not differ in behavioral performance on stop and go trials, but (2) differences in ERPs, particularly in components N200 (index of cognitive control) and P300 (index of attention and inhibition) would be evident. The sample included N = 50 adults with DCD (n = 12), ADHD (n = 9), DCD + ADHD (n = 7), and control participants (n = 22). We replicated that there were no between-group differences for behavioral-level executive performance and motor response inhibition. However, on a physiological level, ERP components N200 and P300 differed between groups, particularly during successful response inhibition. These ERPs reflect potential endophenotypic differences not evident in overt behavior of participants with ADHD and/or DCD. This suggests a disorder specific employment of inhibition or general executive functions in groups of adults with DCD, DCD + ADHD, ADHD, or control participants.

Unique deficit in embodied simulation in autism: An fMRI study comparing autism and developmental coordination disorder

A deficit in pre‐cognitively mirroring other people's actions and experiences may be related to the social impairments observed in autism spectrum disorder (ASD). However, it is unclear whether such embodied simulation deficits are unique to ASD or instead are related to motor impairment, which is commonly comorbid with ASD. Here we aim to disentangle how, neurologically, motor impairments contribute to simulation deficits and identify unique neural signatures of ASD. We compare children with ASD (N = 30) to children with Developmental Coordination Disorder (DCD; N = 23) as well as a typically developing group (N = 33) during fMRI tasks in which children observe, imitate, and mentalize about other people's actions. Results indicate a unique neural signature in ASD: during action observation, only the ASD group shows hypoactivity in a region important for simulation (inferior frontal gyrus, pars opercularis, IFGop). However, during a motor production task (imitation), the IFGop is hypoactive for both ASD and DCD groups. For all tasks, we find correlations across groups with motor ability, even after controlling for age, IQ, and social impairment. Conversely, across groups, mentalizing ability is correlated with activity in the dorsomedial prefrontal cortex when controlling for motor ability. These findings help identify the unique neurobiological basis of ASD for aspects of social processing. Furthermore, as no previous fMRI studies correlated brain activity with motor impairment in ASD, these findings help explain prior conflicting reports in these simulation networks.

Children with developmental coordination disorder show altered functional connectivity compared to peers

Developmental Coordination Disorder (DCD) is a neurodevelopmental disorder that affects a child's ability to learn motor skills and participate in self-care, educational, and leisure activities. The cause of DCD is unknown, but evidence suggests that children with DCD have atypical brain structure and function. Resting-state MRI assesses functional connectivity by identifying brain regions that have parallel activation during rest. As only a few studies have examined functional connectivity in this population, our objective was to compare whole-brain resting-state functional connectivity of children with DCD and typically-developing children. Using Independent Component Analysis (ICA), we compared functional connectivity of 8-12 year old children with DCD (N = 35) and typically-developing children (N = 23) across 19 networks, controlling for age and sex. Children with DCD demonstrate altered functional connectivity between the sensorimotor network and the posterior cingulate cortex (PCC), precuneus, and the posterior middle temporal gyrus (pMTG) (p < 0.0001). Previous evidence suggests the PCC acts as a link between functionally distinct networks. Our results indicate that ineffective communication between the sensorimotor network and the PCC might play a role in inefficient motor learning seen in DCD. The pMTG acts as hub for action-related information and processing, and its involvement could explain some of the functional difficulties seen in DCD. This study increases our understanding of the neurological differences that characterize this common motor disorder.

A Qualitative Photo Elicitation Research Study to elicit the perception of young children with Developmental Disabilities such as ADHD and/or DCD and/or ASD on their participation

Participation, defined as ‘involvement in life situations’ according to the World Health Organisation, is a well-recognized concept and critical indicator of quality of life. In addition it has become an important outcome measure in child rehabilitation. However, little is known about the level of participation of young children with Developmental Disabilities. The aim of this study was to capture their subjective experiences of participation. An adapted informed consent based on a comic strip was used to get the children’s assent. A Photo Elicitation study was used, in which photographs were taken by the children when they were involved in meaningful activities. The photographs were then used to facilitate communication with the children and to initiate in depth-interviews. Forty-seven interviews with 16 children between five and nine years were conducted based on their photographs. This method generated rich data, confirming that young children with Developmental Disabilities were able to inform us accurately on their experiences of participation. Data was analysed by means of an inductive thematic analysis. Results showed that children perceived their participation as satisfying when they can play, learn and join in family gatherings resulting in feelings of inclusion, recognition and belonging. When there are—on occasions—moments that their participation was obstructed, the children used two strategies to resolve it. Or they walked away from it and choose not to participate, or when autonomously motivated for the activity, they relied primarily on their context (i.e. mothers) as enabling their participation. Related to the data, children discussed themes related to their person, activities, connections and mediators between those themes. These themes fit well within earlier and current research on the subject of participation.

Developmental coordination disorder

Developmental coordination disorder (DCD) is a neurodevelopmental disorder that affects children's ability to execute coordinated motor actions, resulting in slow, clumsy, or inaccurate motor performances and learning difficulties (of new motor tasks or to adapt previously learned gestures to a modified or additional constraint). In the course of development, children with DCD exhibit a diversity of motor signs, including fine and gross motor problems with impaired postural control and balance, and sensorimotor coordination or motor learning difficulties. The prevalence ranges between 1.8% and 8%, depending on the diagnostic criteria used, based on the cutoff of motor scores from standardized scales. Four main hypotheses have been postulated to explain DCD in terms of deficits in visuospatial functions, procedural learning, internal modeling, or executive functions. Neuroimaging studies are scarce but have highlighted several brain regions, including the parietal, frontal, and cerebellar cortices. Meta-analyses have supported task-oriented approaches as effective therapies to improve motor performance in children with DCD.

Research Review: Internalising symptoms in developmental coordination disorder: a systematic review and meta-analysis

BACKGROUND

Developmental coordination disorder (DCD) affects 5%-6% of children. There is growing evidence that DCD is associated with greater levels of internalising symptoms (i.e. depression and anxiety). This is the first systematic review and meta-analysis to explore the magnitude of this effect, the quality of the evidence and potential moderators.

METHODS

A systematic search was conducted to identify studies reporting a comparison between individuals with DCD/probable DCD and typically developing (TD) individuals on measures of internalising symptoms. A pooled effect size (Hedges g) was calculated using random-effects meta-analysis. Study quality, publication bias and potential moderators of the effect were explored.

RESULTS

Twenty studies, including a total of 23 subsamples, met the inclusion criteria, of which 22 subsamples were included in the meta-analysis (DCD: n = 1123; TD: n = 7346). A significant, moderate effect of DCD on internalising symptoms was found (g = 0.61). This effect remained robust after accounting for publication bias and excluding lower quality studies. The effect was significantly larger in studies utilising a cross-sectional design (vs. longitudinal), convenience sampling (vs. population screening) and a majority male sample.

CONCLUSIONS

The findings demonstrate that individuals with DCD experience greater levels of internalising symptoms than their peers. This highlights the importance of routine screening for emotional difficulties in DCD, raising awareness of the condition in mental health services and developing psychosocial interventions that extend beyond a focus on motor impairments. However, there is a need for higher quality, longitudinal studies to better understand the causal relationship between DCD and internalising symptoms.

Exercise Interventions in Children and Adolescents With ADHD: A Systematic Review

OBJECTIVE

Exercise has attracted attention as a potential helpful intervention in children with ADHD. Effects are emphasized on cognition, social-emotional, and motor development.

METHOD

A systematic literature search was conducted using the electronic databases Web of Science, PubMed, Scopus, and ERIC to analyze the efficacy of different types of exercise interventions in children and adolescents with ADHD. Seven studies examining the acute and 14 studies examining the long-term effects were included.

RESULTS

The largest effects were reported for mixed exercise programs on ADHD symptomatology and fine motor precision. However, because of the large differences in the study designs, the comparability is limited.

CONCLUSION

At this time, no evidence-based recommendation can be formulated regarding frequency, intensity, or duration of exercise. Nevertheless, some first trends regarding the effects of certain types of exercise can be identified. When focusing on long-term health benefits in children and adolescents with ADHD, qualitative exercise characteristics might play an important role.

Health-related quality of life of children with Developmental Coordination Disorder

BACKGROUND

Although Developmental Coordination Disorder (DCD) is primarily a motor disorder, it can also impact emotional and psychosocial functioning of children with this condition. Evidence suggests that children with DCD experience lower quality of life than their peers, but few studies have explicitly examined the health-related quality of life (HRQOL) of these children.

AIMS

To: (1) describe HRQOL of children with DCD compared to typically-developing children; (2) compare HRQOL from the perspectives of children with DCD and their parents; and (3) explore predictors of HRQOL for children with DCD.

METHODS

Data from the KidScreen-52 and Strength and Difficulties Questionnaire were collected from 50 children with DCD [Mean(SD) age: 9.8 (1.2) years] and their parents and compared to normative data.

RESULTS

Children with DCD and their parents report significantly lower HRQOL compared to published norms. Caregivers have a significantly lower perception of their child's HRQOL than their child's self-report in many domains. Parents of children with DCD report that their children experience significantly more emotional and behavioral disturbances compared to norms. Poor motor function and attentional difficulties predict HRQOL.

CONCLUSION AND IMPLICATIONS

DCD appears to contribute to lower perceived HRQOL. Findings inform therapeutic targets for children with DCD, beyond motor skill intervention.

Effects of Cognitive Control Exertion and Motor Coordination on Task Self-Efficacy and Muscular Endurance Performance in Children

Emerging research shows a strong connection between brain areas governing cognition and motor behavior. Indeed, research based on the Strength Model has shown that people perform worse on physical tasks following the exertion of high (compared to low) cognitive control which has been attributed to the dysregulation of neurophysiological processes within areas of the brain responsible for cognition. Yet, research investigating the negative aftereffects of high cognitive control (HCC) exertion on task performance has not considered the potential role of areas governing motor behavior. The present study investigated the effects of HCC exertion on task self-efficacy and exercise performance in children. A secondary purpose was to investigate whether motor coordination influences the change in exercise performance differently following low versus HCC exertion. Participants (N = 70) performed two isometric handgrip endurance trials separated by a Stroop task, which was either congruent low cognitive control (LCC) or incongruent (HCC). Motor coordination was assessed prior to the first endurance trial. Task self-efficacy for performing the second endurance trial was assessed following the Stroop task. Participants in the HCC condition reported lower task self-efficacy and showed a reduction in endurance exercise performance. Task self-efficacy mediated the cognitive control-performance relationship. Participants scoring lower on motor coordination showed the greatest declines in exercise performance following HCC, whereas motor coordination did not affect performance following LCC. The results of this study provide evidence that task self-efficacy and exercise performance are also negatively affected in children following HCC, and interestingly, these effects are exacerbated among those scoring lower in motor coordination. We recommend future research investigate motor coordination as a potential mechanism for the reductions in both cognitive and physical task performance following the prolonged exertion of HCC.

[Learning disorders in ADHD: How are they related?]

Learning difficulties in general and learning disabilities in particular are almost constant in attention deficit disorder with or without hyperactivity (ADHD). Despite a major research effort, the extent and diversity of these comorbid events still raise many questions about the exact nature of their pathogenetic condition (simple consequences of ADHD or specific related disorders?) and consequently the best way to support them. This article aims to present a brief review of the current data.

Impact of Cerebral Visual Impairments on Motor Skills: Implications for Developmental Coordination Disorders

Cerebral visual impairment (CVI) has become the primary cause of visual impairment and blindness in children in industrialized countries. Its prevalence has increased sharply, due to increased survival rates of children who sustain severe neurological conditions during the perinatal period. Improved diagnosis has probably contributed to this increase. As in adults, the nature and severity of CVI in children relate to the cause, location and extent of damage to the brain. In the present paper, we define CVI and how this impacts on visual function. We then define developmental coordination disorder (DCD) and discuss the link between CVI and DCD. The neuroanatomical correlates and aetiologies of DCD are also presented in relationship with CVI as well as the consequences of perinatal asphyxia (PA) and preterm birth on the occurrence and nature of DCD and CVI. This paper underlines why there are both clinical and theoretical reasons to disentangle CVI and DCD, and to categorize the features with more precision. In order to offer the most appropriate rehabilitation, we propose a systematic and rapid evaluation of visual function in at-risk children who have survived preterm birth or PA whether or not they have been diagnosed with cerebral palsy or DCD.

Defining the neuroanatomic basis of motor coordination in children and its relationship with symptoms of attention-deficit/hyperactivity disorder

BACKGROUND

When children have marked problems with motor coordination, they often have problems with attention and impulse control. Here, we map the neuroanatomic substrate of motor coordination in childhood and ask whether this substrate differs in the presence of concurrent symptoms of attention-deficit/hyperactivity disorder (ADHD).

METHOD

Participants were 226 children. All completed Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5)-based assessment of ADHD symptoms and standardized tests of motor coordination skills assessing aiming/catching, manual dexterity and balance. Symptoms of developmental coordination disorder (DCD) were determined using parental questionnaires. Using 3 Tesla magnetic resonance data, four latent neuroanatomic variables (for the cerebral cortex, cerebellum, basal ganglia and thalamus) were extracted and mapped onto each motor coordination skill using partial least squares pathway modeling.

RESULTS

The motor coordination skill of aiming/catching was significantly linked to latent variables for both the cerebral cortex (t = 4.31, p < 0.0001) and the cerebellum (t = 2.31, p = 0.02). This effect was driven by the premotor/motor cortical regions and the superior cerebellar lobules. These links were not moderated by the severity of symptoms of inattention, hyperactivity and impulsivity. In categorical analyses, the DCD group showed atypical reduction in the volumes of these regions. However, the group with DCD alone did not differ significantly from those with DCD and co-morbid ADHD.

CONCLUSIONS

The superior cerebellar lobules and the premotor/motor cortex emerged as pivotal neural substrates of motor coordination in children. The dimensions of these motor coordination regions did not differ significantly between those who had DCD, with or without co-morbid ADHD.

Coordination difficulty and internalizing symptoms in adults: A twin/sibling study

Increased anxiety and depression symptoms have been reported in individuals with neurodevelopmental disorders, and have been found to be associated with motor coordination difficulties, but little is known about the etiology of these associations. This study aimed to assess genetic, shared (making twins/siblings alike) and non-shared (individual-specific) environmental influences on the association between poor coordination and symptoms of anxiety and depressed mood using a sample of adult twin and sibling pairs. Participants were asked about their coordination skill and anxiety and depression symptoms. About half of the variance in coordination difficulty was explained by familial (combined genetic and shared environmental) influences, with the remaining variance explained by non-shared environmental influences. Phenotypic associations between coordination and anxiety (r=.46) and depression symptoms (r=.44) were largely underpinned by shared familial liability for the three traits. Non-shared environment accounted for about a third of the phenotypic association. Results suggest that both familial and non-shared environmental influences play a role in the etiology of coordination difficulty and its association with internalizing symptoms. The current study highlights that both biological and environmental pathways shared between these symptoms should be examined in future research to inform prevention and treatment approaches in clinical settings.

The Relationship between Motor Skills, Perceived Social Support, and Internalizing Problems in a Community Adolescent Sample

OBJECTIVES

Poor motor skills are associated with a range of psychosocial consequences, including internalizing (anxious and depressive) symptoms. The Elaborated Environmental Stress Hypothesis provides a causal framework to explain this association. The framework posits that motor skills impact internalizing problems through an indirect effect via perceived social support. However, empirical evaluation is required. We examined whether motor skills had an indirect effect on anxious and depressive symptoms via perceived family support domains.

METHODS

This study used a community sample of 93 adolescents (12-16 years). Participants completed measures of motor skills, perceived social support across three dimensions (family, friend, and significant other), depressive symptoms, and anxious symptoms. Age, gender, verbal IQ, and ADHD symptoms were included as control variables.

RESULTS

Regression analysis using PROCESS revealed that motor skills had an indirect effect on depressive symptoms via perceived family support, but not by perceived friend support or significant other support. The negative association between motor skills and anxious symptoms was not mediated by any perceived social support domain.

CONCLUSIONS

Findings are consistent with previous literature indicating an association between motor skills and internalizing problems. However, we identified a different pattern of relationships across anxious and depressive symptoms. While anxiety and depressive symptoms were highly correlated, motor skills had an indirect effect on depressive symptoms via perceived family support only. Our findings highlight the importance of family support as a potential protective factor in the onset of depressive symptoms. This study provides partial support for the Elaborated Environmental Stress Hypothesis, however further research is required.

Meta-analysis of quality of life in children and adolescents with ADHD: By both parent proxy-report and child self-report using PedsQL™

Attention deficit hyperactivity disorder (ADHD) is a prevalent developmental disorder that seriously and negatively impacts a child's health-related quality of life (HRQOL). However, no meta-analysis has been conducted to examine the magnitude of impact, domains affected and factors moderating the impact. This review included nine studies that compared HRQOL of children or adolescents with ADHD with those with typical development using both child self-reports and parent proxy-reports. Seven among nine studies were meta-analytically synthesized to examine the degree of impact of ADHD on children and adolescents, parent-child discrepancy, and the moderators. The results indicate that ADHD impact a child's or adolescent's HRQOL negatively with a moderate effect in physical and a severe effect in psychosocial (i.e., emotional, social, and school) domains. Parental ratings of overall HRQOL in children or adolescents with ADHD were not significantly different from child's ratings when compared with typically developing children and adolescents. Age was negatively associated with all domains of HRQOL in children and adolescents with ADHD both by parent- and child-ratings, and the strongest effect was found in parental ratings of child's emotional HRQOL, with a moderate correlation. This meta-analysis suggests that HRQOL may be assessed in children and adolescents with ADHD both by parent proxy- and child self-reports, and that interventions may be planned accordingly. Future meta-analysis may explore how measures of HRQOL and other factors including child, parental, familiar and school characteristics influence the impact of ADHD and the parent-child agreement in children and adolescents.

The relationship between manual coordination and mental health

Motor coordination impairments frequently co-occur with other developmental disorders and mental health problems in clinically referred populations. But does this reflect a broader dimensional relationship within the general population? A clearer understanding of this relationship might inform improvements in mental health service provision. However, ascertainment and referral bias means that there is limited value in conducting further research with clinically referred samples. We, therefore, conducted a cross-sectional population-based study investigating children's manual coordination using an objective computerised test. These measures were related to teacher-completed responses on a behavioural screening questionnaire [the Strength and Difficulties Questionnaire (SDQ)]. We sampled 298 children (4-11 years old; 136 males) recruited from the general population. Hierarchical (logistic and linear) regression modelling indicated significant categorical and continuous relationships between manual coordination and overall SDQ score (a dimensional measure of psychopathology). Even after controlling for gender and age, manual coordination explained 15 % of the variance in total SDQ score. This dropped to 9 % after exclusion of participants whose SDQ responses indicated potential mental health problems. These results: (1) indicate that there is a clear relationship between children's motor and mental health development in community-based samples; (2) demonstrate the relationship's dimensional nature; and (3) have implications for service provision.

Motor impairment among different psychiatric disorders: Can patterns be identified?

The aim of this study was to explore motor impairment in male adolescents suffering from psychiatric conditions. Taking into account the heterogeneity of a clinical population, motor profiles of distinctive diagnostic groups were evaluated. Whether or not motor ability discriminates between several diagnostic categories was investigated. The Bruininks-Oseretsky Test of Motor Proficiency, Second Edition (BOT-2) was administered to examine a detailed motor profile. The motor abilities of a clinical population (n=144) were compared to those of typically developing peers (n=87), using independent t-tests. To account for differences in intellectual functioning, a one-way ANCOVA was performed. To investigate the extent to which a specific diagnosis contributes to variation in motor scores a stepwise linear regression approach was applied. Results indicated that the clinical group performed significantly worse in comparison to the control group on all BOT-2 scales, even after controlling for IQ. The constructed models indicated that diagnostic categories accounted for a significant amount of the variance in motor ability scores. The results imply that motor ability of adolescents with a psychiatric disorder is in need of attention, regardless of the diagnosis and support the notion that objective motor assessment should be part of routine clinical practice.

Developmental coordination disorder: core sensori-motor deficits, neurobiology and etiology

Among developmental disorders, DCD is one of the least studied and less understood one (Bishop, 2010). This review summarizes the current understanding of developmental coordination disorder in neuropsychology with a focus mainly on high level sensorimotor impairments, its etiology and its neural bases. We summarize these core deficits in the framework of an influent motor control model (Blakemore et al., 2002). DCD has several environmental risk factors which probably interplay with genetic factors but those have not been sufficiently identified. High-level sensori-motor deficits are probably multifactorial in DCD and involve predictive coding deficits as well as weaknesses in perceptual and sensory integration. At the brain level, DCD is associated with impaired structure and functions within the motor network. Throughout the review we highlight exciting new findings as well as potential future lines of research to provide a more comprehensive understanding of this disorder.

Development and applications of the SWAN rating scale for assessment of attention deficit hyperactivity disorder: a literature review

This study reviewed the use of the Strengths and Weaknesses of Attention-Deficit/Hyperactivity-symptoms and Normal-behaviors (SWAN) rating scale in diagnostic and evolutive approaches to attention deficit hyperactivity disorder (ADHD) and in correlational studies of the disorder. A review of articles published in indexed journals from electronic databases was conducted and 61 articles on the SWAN scale were analyzed. From these, 27 were selected to a) examine use of SWAN in research on attention disorders and b) verify evidence of its usefulness in the areas of genetics, neuropsychology, diagnostics, psychiatric comorbidities, neuroimaging, pharmacotherapy, and to examine its statistical reliability and validity in studies of diverse populations. This review of articles indicated a growing use of the SWAN scale for diagnostic purposes, for therapy, and in research on areas other than ADHD, especially when compared with other reliable scales. Use of the scale in ADHD diagnosis requires further statistical testing to define its psychometric properties.

Review: The impact of motor development on typical and atypical social cognition and language: a systematic review

BACKGROUND

Motor development allows infants to gain knowledge of the world but its vital role in social development is often ignored.

METHOD

A systematic search for papers investigating the relationship between motor and social skills was conducted, including research in typical development and in Developmental Coordination Disorder, Autism Spectrum Disorders and Specific Language Impairment.

RESULTS

The search identified 43 studies, many of which highlighted a significant relationship between motor skills and the development of social cognition, language and social interactions.

CONCLUSIONS

This complex relationship requires more attention from researchers and practitioners, allowing the development of more tailored intervention techniques for those at risk of motor, social and language difficulties.

Effects of a summer treatment program on functional sports outcomes in young children with ADHD

Participation in youth sports can be very beneficial, but children with Attention Deficit Hyperactivity Disorder (ADHD) may participate less often and less successfully. The current study evaluated functional sports outcomes for children with ADHD who attended an intensive behavioral treatment program that included a sports training component, and it compared outcomes to children with ADHD who did not attend the program. Results suggest that treatment resulted in significant improvements in many aspects of children's sports functioning, including knowledge of game rules, in vivo game performance, and fundamental skill tasks (motor proficiency, ability to trap a soccer ball appropriately, reduced handball penalties in soccer, and improved ability to catch a baseball). Parents also reported improved sports skills and good sportsmanship in the treatment group. No differences between groups were evident on additional skill tasks evaluating accurately kicking a soccer ball, throwing a baseball, or hitting a baseball off a tee. These results suggest intensive behavioral intervention that includes sports training can significantly improve functional sports outcomes for young children with ADHD.

Developmental delays in children with ADHD

OBJECTIVE

ADHD is often comorbid with other disorders, but it is often assumed that academic, language, or motor c skills problems are secondary to ADHD rather than that attention problems are secondary to the other disorder or both disorders have a shared etiology. We assessed for comorbid developmental disorders and which cognitive processes were impaired in children with ADHD.

METHOD

Measures of intelligence, language, motor skills, social cognition, and executive functions were administered to children with ADHD (n = 53) and age/sex-matched typical children.

RESULTS

Clinically significant deficits were 2 to 7 times as common in children with ADHD as in typical children, and the structure of ability differed in the two groups. Abilities were less differentiated in children with ADHD.

CONCLUSION

The results indicate a need for comprehensive screening for developmental disorders in children with ADHD and imply that research needs to focus on how ADHD and developmental disorders may share an etiology.

Psychological distress in children with developmental coordination disorder and attention-deficit hyperactivity disorder

This study explored whether or not a population-based sample of children with developmental coordination disorder (DCD), with and without comorbid attention deficit/hyperactivity disorder (ADHD), experienced higher levels of psychological distress than their peers. A two-stage procedure was used to identify 244 children: 68 with DCD only, 54 with ADHD only, 31 with comorbid DCD and ADHD, and 91 randomly selected typically developing (TD) children. Symptoms of depression and anxiety were measured by child and parent report. Child sex and caregiver ethnicity differed across groups, with a higher ratio of boys to girls in the ADHD only group and a slightly higher proportion of non-Caucasian caregivers in the TD group. After controlling for age, sex, and caregiver ethnicity, there was significant variation across groups in both anxiety (by parent report, F(3,235)=8.9, p<0.001; by child report, F(3,236)=5.6, p=0.001) and depression (parent report, F(3,236)=23.7, p<0.001; child report, F(3,238)=9.9, p<0.001). In general, children in all three disorder groups had significantly higher levels of symptoms than TD children, but most pairwise differences among those three groups were not significant. The one exception was the higher level of depressive symptoms noted by parent report in the ADHD/DCD group. In conclusion, children identified on the basis of motor coordination problems through a population-based screen showed significantly more symptoms of depression and anxiety than typically developing children. Children who have both DCD and ADHD are particularly at heightened risk of psychological distress.