Mathematical problems in children with developmental coordination disorder

Finger counting to relieve working memory in children with developmental coordination disorder: Insights from behavioral and three-dimensional motion analyses

A limited number of studies have attempted to understand how motor deficits affect numerical abilities in children with developmental coordination disorder (DCD). The purpose of this study was to explore the functionality of finger-counting (FC) in children with DCD. The participants, 15 children with DCD and 15 typically developing (TD) children matched on school level and fluid reasoning abilities, were asked to use FC to solve an ordinal task with high working memory (WM) load. Behavioral measures supplemented with biomechanical measures, from three-dimensional motion analysis synchronized to a voice recording were used to assess children's performance and FC functionality (total duration, inter-finger [IF] transition, IF variance, finger/voice synchronization, and automatization of FC movements). Children with DCD were less accurate than TD children in using FC to solve ordinal problems with high WM load. This group difference could not be accounted for by poor FC skills given that FC movement turned out to be as functional in children with DCD as in their TD peers. When added to the model as a covariate, WM captured a greater proportion of intergroup variability than manual dexterity, further suggesting that their difficulties would be better accounted for by limited WM resources than by fine motor skills.

Maths performance of adults with and without developmental coordination disorder (DCD): The role of working memory and maths anxiety

Previous studies have shown that children with Developmental Coordination Disorder (DCD)/Dyspraxia have poorer maths performance compared to their neurotypical (NT) counterparts. However, no studies have explored the cognitive and emotional factors affecting the maths performance of adults with DCD. This study, therefore, investigated the role of working memory (WM), maths anxiety (MAS), and maths self-efficacy on the maths performance of adults with DCD. We found that adults with DCD had lower WM and maths performance and were more maths anxious than their NT peers. However, there were no significant differences in maths self-efficacy. When looking at the predictors of maths performance, we found a positive relationship between WM resources and the DCD maths performance, possibly indicating that they relied more on WM resources to perform simple mental arithmetic tasks than NTs. On the other hand, MAS had an inverse relationship with the NT maths performance but not with the DCD performance. The reasons and implications of these findings will be discussed.

Factors associated with mathematical capacity in children with Developmental Coordination Disorder

BACKGROUND

Developmental Coordination Disorder (DCD) is a condition characterized by difficulties in motor planning and coordination and affects 5 to 6% of all school-aged children. Children with DCD frequently present with difficulties with academic activities such as handwriting. However, no study to date has comprehensively described mathematical capacity and its potential associated factors in this high-risk group.

AIMS

We aimed to describe the frequency and nature of mathematical difficulties of school-aged children with DCD and to evaluate potential factors associated with mathematical performance.

METHODS

A total of 55 elementary school-aged children with DCD underwent comprehensive standardized assessments of mathematical, visuoperceptual (VP), attentional, visual-motor integration (VMI), and motor skills. The contribution of each factor to mathematical capacity was established using hierarchical multivariate linear regression models.

RESULTS

Children with DCD (9.1 ± 1.5 years, 44 males) had lower overall mathematical capacity compared to normative data (-0.59 SD) on the KeyMath 3rd edition, with poorer performance in basic concepts and problem-solving. Thirty-eight percent of the sample performed below the 15th percentile in overall mathematical skills. VP skills were the most important factors associated with most mathematical domains. Thirty-four percent of the variance of overall mathematical capacity was explained by VP skills, inattention, VMI and motor impairments while controlling for household income (F [5,49]=5.029, p < .0001).

CONCLUSION

Children with DCD present with mathematical difficulties in basic concepts and problem-solving, which are partially explained by VP skills. Our findings stress the important of systematically assessing mathematical difficulties children with DCD to ensure they receive the necessary support that leads to academic success.

The componential nature of arithmetical cognition: some important questions

Research on typically developing children and adults and people with developmental and acquired dyscalculia converges in indicating that arithmetical ability is not unitary but is made up of many different components. Categories of components include non-symbolic quantity representation and processing; symbolic quantity representation and processing; counting procedures and principles; arithmetic operations; arithmetical knowledge and understanding; multiple forms and applications of conceptual knowledge of arithmetic; and domain-general abilities such as attention, executive functions and working memory. There is much evidence that different components can and often do show considerable functional independence, not only in developmental and acquired dyscalculia, but in typically achieving children and adults. At the same time, it is possible to find complex interactions and bidirectional relationships between the different components, including between domain-specific and apparently domain-general abilities. There is a great deal that still needs to be discovered. In particular, we need to learn more about the origins in infancy of subitizing and approximate magnitude comparison, the extent to which these interact, the extent to which they may be further divisible, and the extent and ways in which they themselves may develop with age and the extent to which they may influence later-developing components. There also needs to be a lot more research on exactly how domain-general and domain-specific abilities contribute to mathematical development, and how they interact with one another.

Motor and cognitive skills implicated in the Motor Observation Questionnaire for Teachers (MOQ-T): A multidisciplinary approach

This study was designed to determine the relationship between an observational measure of motor skills for teachers (i.e., MOQ-T), age, and some objectively assessed cognitive and motor indices. Two further goals were to examine which motor and cognitive factors predicted MOQ-T scores and to explore whether pupils with very low motor skills identified through MOQ-T also exhibited lower scores on objectively assessed motor and visuo-spatial tasks. A sample of 156 pupils aged 8.4 years-11.3 years and attending Italian primary school completed a battery of tests assessing writing speed, visuo-spatial abstract reasoning, fluency, and static balance abilities objectively assessed by measuring postural sway. Small to medium associations were found between MOQ-T scores and age, motor, and cognitive parameters, respectively. Moreover, approximately 26% of the variance in MOQ-T was predicted by sway area in the eyes-open condition, visuo-spatial fluency, and writing speed. Finally, pupils at risk of developmental coordination disorder exhibited poorer writing speed, and motor and higher-order visuo-spatial deficits. In conclusion, the synergistic use of objective measures of motor and cognitive functioning and observational screening questionnaires such as MOQ-T should be encouraged at school to identify pupils at risk of developmental coordination disorder.

Reading numbers is harder than reading words: An eye-tracking study

We recorded the eye movements of adults reading aloud short (four digit) and long (eight to 11 digit) Arabic numerals compared to matched-in-length words and pseudowords. We presented each item in isolation, at the center of the screen. Participants read each item aloud at their pace, and then pressed the spacebar to display the next item. Reading accuracy was 99 %. Results showed that adults make 2.5 times more fixations when reading short numerals compared to short words, and up to 7 times more fixations when reading long numerals with respect to long words. Similarly, adults make 3 times more saccades when reading short numerals compared to short words, and up to 9 times more saccades when reading long numerals with respect to long words. Fixation duration and saccade amplitude stay almost the same when reading short numerals with respect to short words. However, fixation duration increases by ∼50 ms when reading long numerals (∼300 ms) with respect to long words (∼250 ms), and saccade amplitude decreases up to 0.83 characters when reading long numerals with respect to long words. The pattern of findings for long numerals-more and shorter saccades as well as more and longer fixations-shows the extent to which reading long Arabic numerals is a cognitively costly task. Within the phonographic writing system, this pattern of eye movements stands for the use of the sublexical print-to-sound correspondence rules. The data highlight that reading large numerals is an unautomatized activity and that Arabic numerals must be converted into their oral form by a step-by-step process even by expert readers.

Cognition and maths in children with Attention-Deficit/Hyperactivity disorder with and without co-occurring movement difficulties

BACKGROUND

Movement difficulties are common in ADHD, however, the implications of their co-occurrences on cognitive and maths performance is unknown.

AIMS

This study set out to examine whether cognitive and maths performance of children with high ADHD symptoms differs depending on the co-occurrence of movement difficulties given evidence that weaker visuospatial processing, known to be important for maths performance, differentiates ADHD and DCD. We also aimed to examine whether relationships between cognition and maths in ADHD differs depending on co-occurring movement difficulties.

METHODS

Participants were 43 drug naïve children between 6 and 12 years old (M = 101.53 months SD = 19.58). The ADHD-only group (n = 18) included children with high ADHD scores, and those in the ADHD+DCD group (n = 25) concurrently had high movement difficulty scores. All completed executive function and memory, including 2 visuo-spatial memory tasks from the CANTAB battery and Mathematics Problem Solving, Numeracy, and Maths Fluency tasks from the WIAT-III and specific factual, conceptual, and procedural maths component tasks.

RESULTS

Children in the ADHD+DCD group scored significantly lower on visuospatial working memory (WM) capacity, than those in the ADHD-only group. Both groups were comparable on all other cognitive assessments of executive functions, memory, and processing speed. The groups did not differ in their maths attainment scores, nor on more specific maths skills. Comparison of the correlations between cognitive processes and maths revealed that the association between visuospatial WM updating and procedural skill efficiency was stronger for the ADHD-only group. Moreover, associations between visuospatial WM and maths problem solving attainment were stronger in the ADHD+DCD group.

CONCLUSIONS

Despite similarities in maths performance, children with ADHD+DCD could be distinguished by lower visuospatial WM. Differential associations with some of the maths domain implicate recruitment of different cognitive processes for some aspects of maths. This distinction can be particularly useful for conceptualising cognitive characteristics of different clinical groups and understanding cognitive pathways of maths difficulties. Implications for interventions are discussed.

Academic Challenges in Developmental Coordination Disorder: A Systematic Review and Meta-Analysis

AIMS

Developmental Coordination Disorder (DCD) is a chronic condition affecting motor coordination in daily activities. While motor difficulties are well documented in this population, it is unclear how frequent and to what extent academic activities are affected. This systematic review aims to comprehensively summarize the knowledge regarding the prevalence and extent of academic difficulties in reading, writing and mathematics in school-aged children with DCD.

METHODS

Two independent reviewers analyzed original studies on academic difficulties in school-aged children with DCD. A binary random-effects model was used to calculate the pooled prevalence by academic difficulty. A random-effects model using standardized mean differences (g statistic) was calculated to estimate the extent of the academic difficulties.

RESULTS

Twenty-four studies were included. A pooled prevalence of 84% of handwriting difficulties and 89.5% of mathematical difficulties was reported. No pooled prevalence of difficulties could be calculated for the other academic outcomes. Children with DCD present with poorer performance in handwriting legibility (g = -1.312) and speed (g = -0.931), writing (g = -0.859), mathematics (g = -1.199) and reading (g = -1.193).

CONCLUSIONS

This review highlights the high frequency and severity of academic difficulties in children with DCD, specifically in mathematics, which stresses the importance of evaluating academic performance to target interventions to support optimal functioning in daily life.

Cognitive factors and educational placement affecting mathematical attainment in middle school students with mild intellectual disability

The study investigated the relationship between mathematics achievement, cognitive and motor skills, and general intellectual ability among seventy 10-12 years old students with mild intellectual disability (MID) attending regular school (n = 30) and special school (n = 40). The purpose of the study was to identify the critical deficits teachers need to consider when teaching mathematics at the secondary school level. The students attending regular schools had significantly higher fluid intelligence scores (p = 0.036), but we found no difference in the total score of the math achievement test. Special school students were more eager to use assistance and aids when solving math problems (p = 0.040). The study indicated significant associations between basic mathematical skills, verbal and visuospatial processing, and motor skills. Thus, it is essential to compensate for the delay of students' cognitive development to improve their basic mathematical skills and, in general, mathematical performance. The educational placement affects the willingness or ability to seek academic help when solving mathematical problems.

The Relationship between Motor Coordination Ability, Cognitive Ability, and Academic Achievement in Japanese Children with Autism Spectrum Disorder and Attention Deficit/Hyperactivity Disorder

Motor coordination abilities are related to cognitive abilities and academic achievement in children with neurodevelopmental disorders. However, the similarities and differences of these relationships in children with autism spectrum disorder (ASD) and attention deficit/hyperactivity disorder (AD/HD) have not been explored. The purpose of this study was to investigate the relationship between motor coordination abilities, cognitive abilities, and academic achievement in Japanese children with ASD and AD/HD. Participants included 20 children with ASD, 20 children with AD/HD, and 20 typically developing children, matched for age and gender. Their motor coordination abilities were assessed with the Movement Assessment Battery for Children-2 (MABC-2). Furthermore, cognitive ability and academic achievement were assessed with the Kauffman Assessment Battery for Children-II (K-ABCII). Results demonstrated that the MABC-2 Total score significantly correlated with the K-ABCII Simultaneous processing, Planning, Total cognitive ability, Writing and Arithmetic scores in children with ASD. However, in children with AD/HD, there was no significant correlation between MABC-2 and K-ABCII subscale scores. The results of this study indicated that the relationship between motor coordination ability, cognitive ability, and academic achievement differs between ASD and AD/HD. This difference might indicate the non-similarity of neurological characteristics and encourage consideration for an approach that accommodates the features of neurodevelopmental disorders in children.

The Impact of School Strategies and the Home Environment on Home Learning Experiences During the COVID-19 Pandemic in Children With and Without Developmental Disorders

Using the Opportunity-Propensity Model (Byrnes in Dev Rev 56:100911, 2020; Byrnes & Miller in Contemp Educ Psychol 32(4);599–629, 2007), the current study investigated which factors helped predicting children’s home learning experiences during the COVID-19 pandemic, thereby examining differences between children with (DD; n = 779) and without (TD; n = 1443) developmental disorders. MANCOVA results indicated more negative experiences for DD children and their parents. SEM-results revealed the alignment between different teachers and autonomous motivation in children as the most important predictors for the outcome variables. Less predictors were significant for DD as compared to TD children which suggests other factors are at play in the DD group. Limitations, strengths and suggestions for future research are being discussed, together with some implications for classroom practices and remote learning approaches.

Do executive functions and gross motor skills predict writing and mathematical performance in children with developmental coordination disorder?

Aim: To examine whether executive functions, and gross motor skills were predictors for school performance in children with DCD, with risk for DCD (r-DCD), and with typical development (TD).Methods: Participants were 63 children with DCD (M_age = 8.70, SD_age = .64), 31 children with r-DCD (M_age = 8.90, SD_age = 0.74), and 63 typical development children (M_age = 8.74, SD_age = .63). Wechsler Abbreviated Scale of Intelligence, Movement Assessment Battery for Children-2, Test of Gross Motor Development-3, Oral Word Span in Sentences, Odd-One-Out, Go/No-Go, Hayling Test, Trail Making Test, Five Digits Test, and the Test of School Performance-II were utilized.Results: In DCD, processing speed (β = -.42, p = .005), and auditory-motor inhibition (β = -.36, p = .009), and auditory-verbal inhibition (β = -.38, p = .023) predicted math performance; and auditory-motor (β = -.40, p = .38) and visuospatial working memory (β = -.33 p = .011) predicted writing performance. In r-DCD, auditory-motor (β = - .67; p = .002) and visual-motor (β = -.40; p = .040) inhibition predicted math performance; visual-motor inhibition predicted writing performance (β = -.47; p = .015).Conclusion: Lower inhibitory control and visuospatial working memory scores affect children with DCD and r-DCD' school performance.

Evaluating the Factor Structure and Criterion Validity of the Canadian Little DCDQ: Associations Between Motor Competence, Executive Functions, Early Numeracy Skills, and ADHD in Early Childhood

The Canadian Little Developmental Coordination Disorder Questionnaire (Little DCDQ-CA) is a parent-report screening instrument that identifies 3- to 4-year-old children who may be at risk for Developmental Coordination Disorder (DCD). We tested the factor structure and criterion validity of the Little DCDQ-CA in a sample of preschool-aged children in the United States (N = 233). Factor analysis indicated that the DCDQ-CA was best represented by one factor. Using cutoff scores that were proposed by the developer, 45% of the sample was identified as at-risk for DCD. Although a much larger percentage of children was identified as at-risk than would be expected based on the prevalence of formal DCD diagnoses in the population, the Little DCDQ-CA demonstrated good criterion validity. Specifically, compared with their peers, children who exceeded the at-risk criterion demonstrated worse motor competence, executive functioning skills, and early numeracy skills and were rated as having greater ADHD behaviors by their teachers, all consistent with expectations for children who are at risk for DCD. Results are discussed as they relate to future use of the Little DCDQ-CA.

International clinical practice recommendations on the definition, diagnosis, assessment, intervention, and psychosocial aspects of developmental coordination disorder - Chinese (Mandarin) translation

目的

本国际临床指南由欧洲残疾儿童学会（the European Academy of Childhood Disability，EACD）牵头制定，旨在解决发育性协调障碍（developmental coordination disorder，DCD）的定义、诊断、评估、干预以及与社会心理方面的临床应用关键问题。

方法

本指南针对五个领域的关键问题，通过文献综述和专家团队的正式讨论达成共识。为保证指南的循证基础，以“机制”、“评估”和“干预”为检索词, 对2012年更新以来提出的最新建议以及新增的“社会心理问题”和“青少年/成人”为检索词进行检索。根据牛津大学循证医学中心证据等级 (证据水平 [level of evidence, LOE]1–4) 将结果进行分类，最终转化为指南建议。并由国际、多学科专家小组举行了两次会议，5个回合的Delphi 专家问卷调查，制定了高质量临床应用实践 (good clinical practice，GCP) 。

结果

本指南共制定35条建议。其中8条以文献综述为依据 (3 条涉及“评估”，5条涉及“干预”)； 22 条在 2012 年指南的基础上进行了更新；其他为涉及诊断、评估 (3条GCP) 及社会心理问题 (2 条 GCP) 的新建议。此外，其中有1条(LOE)新建议提出视频游戏可作为以活动和参与为导向的传统干预措施的辅助手段，并针对青少年和成人DCD提出了 2 条新建议 (1 条 GCP，1 条 LOE)。

结论

本指南是基于当前的研究证据和专家共识对DCD进行全面概述。它反映了不同学科临床和科研人员的最新科技水平。本国际指南可作为各国制定指南的基础。

Take it of your shoulders: Providing scaffolds leads to better performance on mathematical word problems in secondary school children with developmental coordination disorder

BACKGROUND

Many children with developmental coordination disorder (DCD) have mathematical problems which are more pronounced for mathematical skills that also require executive functions. Although empirical evidence is missing, math and special education need teachers of children with DCD report difficulties with mathematical word problem solving that can be remediated by providing the children with scaffolds cueing the intermediate steps.

AIMS

This study aims to find empirical evidence for the effectivity of such additional support. In addition, we want to investigate whether the difficulties are due to inefficient arithmetic or executive functioning skills.

METHODS AND PROCEDURES

A DCD and a control group solved word problems with and without scaffolds and conducted a series of tasks measuring calculation and executive skills.

OUTCOMES AND RESULTS

Performance improves when scaffolds are presented to children with DCD. Children with DCD and control children differ on executive functioning tasks but perform similarly on arithmetic tests.

CONCLUSIONS AND IMPLICATIONS

Providing scaffolds for word problem solving is effective in children with DCD. Scaffolds possibly reduce the required cognitive load, making the problem solvable for DCD children that have reduced executive functioning skills.

Subitizing and counting impairments in children with developmental coordination disorder

Developmental coordination disorder (DCD) interferes with academic achievement and daily life, and is associated with persistent academic difficulties, in particular within mathematical learning. In the present study, we aimed to study numerical cognition using an approach that taps very basic numerical processes such as subitizing and counting abilities in DCD. We used a counting task and a subitizing task in forty 7-10 years-old children with or without DCD. In both tasks, children were presented with arrays of one to eight dots and asked to name aloud the number of dots as accurately and quickly as possible. In the subitizing task, dots were presented during 250 ms whereas in the counting task they stayed on the screen until the participants gave a verbal response. The results showed that children with DCD were less accurate and slower in the two enumeration tasks (with and without a time limit), providing evidence that DCD impairs both counting and subitizing. These impairments might have a deleterious impact on the ability to improve the acuity of the Approximate Number System through counting, and thus could play a role in the underachievement of children with DCD in mathematics.

Putting a Finger on Numerical Development - Reviewing the Contributions of Kindergarten Finger Gnosis and Fine Motor Skills to Numerical Abilities

The well-documented association between fingers and numbers is not only based on the observation that most children use their fingers for counting and initial calculation, but also on extensive behavioral and neuro-functional evidence. In this article, we critically review developmental studies evaluating the association between finger sensorimotor skills (i.e., finger gnosis and fine motor skills) and numerical abilities. In sum, reviewed studies were found to provide evidential value and indicated that both finger gnosis and fine motor skills predict measures of counting, number system knowledge, number magnitude processing, and calculation ability. Therefore, specific and unique contributions of both finger gnosis and fine motor skills to the development of numerical skills seem to be substantiated. Through critical consideration of the reviewed evidence, we suggest that the association of finger gnosis and fine motor skills with numerical abilities may emerge from a combination of functional and redeployment mechanisms, in which the early use of finger-based numerical strategies during childhood might be the developmental process by which number representations become intertwined with the finger sensorimotor system, which carries an innate predisposition for said association to unfold. Further research is nonetheless necessary to clarify the causal mechanisms underlying this association.

Executive function in children with and without developmental coordination disorder: A comparative study

BACKGROUND

Children with motor impairments also show poor performance in some executive functions' components. However, there is no consensus on which specific executive subdomain is more impacted.

AIM

The objective of this study was to compare executive functions in children with developmental coordination disorder (DCD), at risk for DCD (r-DCD), and in typically developing (TD) children.

METHODS AND PROCEDURES

A sample of 397 children was assessed using the MABC-2. Two groups of children were identified; DCD (n = 63) and at r-DCD (n = 31). A third matched group of children with TD (n = 63) was formed. The MABC-2 checklist and the WASI tests were used as screening tools. Measures of executive function including verbal and nonverbal tasks for working memory, inhibitory control, and cognitive flexibility were tested. Multivariate analysis of variance followed by analyses of variance and Bonferroni tests were used to verify group effects on executive functions.

RESULTS

A significant group effects were found for Working Memory, Λ = .78, F(4, 360) = 10.12, p ≤ .001, η_p² = .12; Inhibitory Control, Λ = .59, F(16, 294) = 5.48, p ≤ .001, η_p² = .23; and Cognitive Flexibility and Inhibitory Control, Λ = .60, F(22, 288) = 3.74, p ≤ .001, η_p² = .22, with moderate effect sizes. The DCD group showed lower scores compared with the TD group on the visuospatial and verbal working memory; inhibitory control and in tasks of cognitive flexibility; the r-DCD group showed lower scores compared with the TD group for visuospatial working memory and for cognitive flexibility.

CONCLUSIONS AND IMPLICATIONS

Poor performance in several measures of executive functions in children with DCD emphasized the need of motor/executive task-specific interventions. Furthermore, children at r-DCD showed low scores in several executive functions; therefore, preventive services should also be provided for this subclinical group.

The synergistic effect of poor motor coordination, gender and age on self-concept in children: A longitudinal analysis

BACKGROUND

Self-concept is a critical psychosocial outcome in childhood that is shaped by many factors. Gender, motor coordination and age have been identified as three important contributors.

AIM

The present study examined whether poor motor coordination (i.e., being classified as at risk for Developmental Coordination Disorder [rDCD]), gender and age have a synergistic effect on domains of self-concept and self-worth in children.

METHODS

Data were derived from the Physical Health and Activity Study Team longitudinal open cohort project. Children enrolled in grade 4 (M_age = 9.88 ± 0.35) at baseline (n = 1978) completed the Self-Perception Profile for Children 7 times over 4 years to evaluate their competence across multiple domains. The Bruininks-Oseretsky Test of Motor Proficiency - Short Form was completed once to evaluate children's motor coordination. Participants scoring ≤15th percentile were classified as rDCD.

RESULTS

A significant 3-way interaction between rDCD, gender and age was observed for athletic ability, physical appearance and academic competence, but not social competence, behavioural conduct or global self-worth. Findings revealed developmental trajectories for self-perceptions of athletic ability, physical appearance, and academic competence were lowest among rDCD girls. Boys classified as rDCD also demonstrated lower athletic, academic and physical self-perceptions in comparison to typically developing children.

CONCLUSIONS

Age intensifies disparities in self held athletic, physical and academic perceptions attributable to differences in gender and rDCD status, however, differences in these domains appear to be independent of children's overall views of themselves.

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.

International clinical practice recommendations on the definition, diagnosis, assessment, intervention, and psychosocial aspects of developmental coordination disorder

AIM

These international clinical practice recommendations (CPR) for developmental coordination disorder (DCD), initiated by the European Academy of Childhood Disability (EACD), aim to address key questions on the definition, diagnosis, assessment, intervention, and psychosocial aspects of DCD relevant for clinical practice.

METHOD

Key questions in five areas were considered through literature reviews and formal expert consensus. For recommendations based on evidence, literature searches on 'mechanisms', 'assessment', and 'intervention' were updated since the last recommendations in 2012. New searches were conducted for 'psychosocial issues' and 'adolescents/adults'. Evidence was rated according to the Oxford Centre for Evidence-Based Medicine (level of evidence [LOE] 1-4) and transferred into recommendations. For recommendations based on formal consensus, two meetings of an international, multidisciplinary expert panel were conducted with a further five Delphi rounds to develop good clinical practice (GCP) recommendations.

RESULTS

Thirty-five recommendations were made. Eight were based on the evidence from literature reviews (three on 'assessment', five on 'intervention'). Twenty-two were updated from the 2012 recommendations. New recommendations relate to diagnosis and assessment (two GCPs) and psychosocial issues (three GCPs). Additionally, one new recommendation (LOE) reflects active video games as adjuncts to more traditional activity-oriented and participation-oriented interventions, and two new recommendations (one GCP, one LOE) were made for adolescents and adults with DCD.

INTERPRETATION

The CPR-DCD is a comprehensive overview of DCD and current understanding based on research evidence and expert consensus. It reflects the state of the art for clinicians and scientists of varied disciplines. The international CPR-DCD may serve as a basis for national guidelines.

WHAT THIS PAPER ADDS

Updated international clinical practice guidelines on developmental coordination disorder (DCD). Refined and extended recommendations on clinical assessment and intervention for DCD. A critical synopsis of current research on mechanisms of DCD. A critical synopsis of psychosocial issues in DCD, with implications for clinical practice. The first international recommendations to consider adolescents and adults with DCD.

Hitting the Target: Mathematical Attainment in Children Is Related to Interceptive-Timing Ability

Interceptive timing is a fundamental ability underpinning numerous actions (e.g., ball catching), but its development and relationship with other cognitive functions remain poorly understood. Piaget suggested that children need to learn the physical rules that govern their environment before they can represent abstract concepts such as number and time. Thus, learning how objects move in space and time may underpin the development of related abstract representations (i.e., mathematics). To test this hypothesis, we captured objective measures of interceptive timing in 309 primary school children (5-11 years old), alongside scores for general motor skill and national standardized academic attainment. Bayesian estimation showed that interceptive timing (but not general motor capability) uniquely predicted mathematical ability even after we controlled for age, reading, and writing attainment. This finding demonstrates that interceptive timing is distinct from other motor skills with specificity in predicting childhood mathematical ability independently of other forms of attainment and motor capability.

Cognitive predictors of sequential motor impairments in children with dyslexia and/or attention deficit/hyperactivity disorder

This study examined cognitive predictors of sequential motor skills in 215 children with dyslexia and/or attention deficit/hyperactivity disorder (ADHD). Visual working memory and math fluency abilities contributed significantly to performance of sequential motor abilities in children with dyslexia (N = 67), ADHD (N = 66) and those with a comorbid diagnosis (N = 82), generally without differentiation between groups. In addition, primary diagnostic features of each disorder, such as reading and inattention, did not contribute to the variance in motor skill performance of these children. The results support a unifying framework of motor impairment in children with neurodevelopmental disorders such as dyslexia and ADHD.

Relationship between Motor Coordination, Cognitive Abilities, and Academic Achievement in Japanese Children with Neurodevelopmental Disorders

Background/Objective

Motor coordination impairment is common in children with neurodevelopmental disorders such as autism spectrum disorder (ASD) and attention deficit/hyperactivity disorder (AD/HD). The purpose of this study was to investigate the relationship between motor coordination, cognitive ability, and academic achievement in Japanese children with neurodevelopmental disorders.

Methods

Thirty-four school-age (6–12 years old) children with neurodevelopmental disorders and 34 age-matched typically developing (TD) children were recruited in this study. Correlations between the scores of the Movement Assessment Battery for Children-2 (M-ABC2) and the Kaufman Assessment Battery for Children — Second Edition (K-ABCII) that assesses cognitive abilities, and academic achievement were analyzed.

Results

The children with neurodevelopmental disorders obtained a lower total score and all component scores on M-ABC2 compared to the TD children. In children with neurodevelopmental disorders, M-ABC2 Manual Dexterity score was significantly correlated with K-ABCII Simultaneous Processing (r = .345, p = .046), Knowledge (r = .422, p = .013), Reading (r = .342, p = .048), Writing (r = .414, p = .017), and Arithmetic (r = .443, p = .009) scores. In addition, M-ABC2 Balance score was significantly correlated with K-ABCII Learning (r = .341, p = .048), Writing (r = .493, p = .004), and Arithmetic (r = .386, p = .024) scores.

Conclusion

These findings stress that it is essential to accurately identify motor coordination impairments and the interventions that would consider motor coordination problems related to cognitive abilities and academic achievement in Japanese children with neurodevelopmental disorders.

Counting on the mental number line to make a move: sensorimotor ('pen') control and numerical processing

Mathematics is often conducted with a writing implement. But is there a relationship between numerical processing and sensorimotor 'pen' control? We asked participants to move a stylus so it crossed an unmarked line at a location specified by a symbolic number (1-9), where number colour indicated whether the line ran left-right ('normal') or vice versa ('reversed'). The task could be simplified through the use of a 'mental number line' (MNL). Many modern societies use number lines in mathematical education and the brain's representation of number appears to follow a culturally determined spatial organisation (so better task performance is associated with this culturally normal orientation-the MNL effect). Participants (counter-balanced) completed two consistent blocks of trials, 'normal' and 'reversed', followed by a mixed block where line direction varied randomly. Experiment 1 established that the MNL effect was robust, and showed that the cognitive load associated with reversing the MNL not only affected response selection but also the actual movement execution (indexed by duration) within the mixed trials. Experiment 2 showed that an individual's motor abilities predicted performance in the difficult (mixed) condition but not the easier blocks. These results suggest that numerical processing is not isolated from motor capabilities-a finding with applied consequences.

Short-Term Effects of Methylphenidate on Math Productivity in Children With Attention-Deficit/Hyperactivity Disorder are Mediated by Symptom Improvements: Evidence From a Placebo-Controlled Trial

BACKGROUND

Although numerous studies report positive effects of methylphenidate on academic performance, the mechanism behind these improvements remains unclear. This study investigates the effects of methylphenidate on academic performance in children with attention-deficit/hyperactivity disorder (ADHD) and the mediating and moderating influence of ADHD severity, academic performance, and ADHD symptom improvement.

METHODS

Sixty-three children with ADHD participated in a double-blind placebo-controlled crossover study comparing the effects of long-acting methylphenidate and placebo. Dependent variables were math, reading, and spelling performance. The ADHD group performance was compared with a group of 67 typically developing children.

RESULTS

Methylphenidate improved math productivity and accuracy in children with ADHD. The effect of methylphenidate on math productivity was partly explained by parent-rated symptom improvement, with greater efficacy for children showing more symptom improvement. Further, children showing below-average math performance while on placebo profited more from methylphenidate than children showing above-average math performance.

CONCLUSIONS

The results from this study indicate positive effects of methylphenidate on academic performance, although these were limited to math abilities. In light of these results, expectations of parents, teachers, and treating physicians about the immediate effects of methylphenidate on academic improvement should be tempered. Moreover, our results implicate that positive effects of methylphenidate on math performance are in part due directly to effects on math ability and in part due to reductions in ADHD symptoms.

Numerical abilities of school-age children with Developmental Coordination Disorder (DCD): A behavioral and eye-tracking study

Developmental Coordination Disorder (DCD) is a disorder of motor coordination which interferes with academic achievement. Difficulties in mathematics have been reported. Performance in the number line task is very sensitive to atypical development of numerical cognition. We used a position-to-number task in which twenty 7-to-10years old children with DCD and 20 age-matched typically developing (TD) children had to estimate the number that corresponded to a hatch mark placed on a 0-100 number line. Eye movements were recorded. Children with DCD were less accurate and slower to respond than their peers. However, they were able to map numbers onto space linearly and used anchoring strategies as control. We suggest that the shift to a linear trend reflects the ability of DCD children to use efficient strategies to solve the task despite a possibly more imprecise underlying numerical acuity.

Mathematical difficulties in developmental coordination disorder: Symbolic and nonsymbolic number processing

At school, children with Developmental Coordination Disorder (DCD) struggle with mathematics. However, little attention has been paid to their numerical cognition abilities. The goal of this study was to better understand the cognitive basis for mathematical difficulties in children with DCD. Twenty 7-to-10 years-old children with DCD were compared to twenty age-matched typically developing children using dot and digit comparison tasks to assess symbolic and nonsymbolic number processing and in a task of single digits additions. Results showed that children with DCD had lower performance in nonsymbolic and symbolic number comparison tasks than typically developing children. They were also slower to solve simple addition problems. Moreover, correlational analyses showed that children with DCD who experienced greater impairments in the nonsymbolic task also performed more poorly in the symbolic tasks. These findings suggest that DCD impairs both nonsymbolic and symbolic number processing. A systematic assessment of numerical cognition in children with DCD could provide a more comprehensive picture of their deficits and help in proposing specific remediation.

Neuropsychopathological comorbidities in learning disorders

BACKGROUND

Learning Disorders (LD) are complex diseases that affect about 2-10% of the school-age population. We performed neuropsychological and psychopathological evaluation, in order to investigate comorbidity in children with LD.

METHODS

Our sample consisted of 448 patients from 7 to 16 years of age with a diagnosis of LD, divided in two subgroups: Specific Learning Disorders (SLD), including reading, writing, mathematics disorders, and Learning Disorders Not Otherwise Specified (LD NOS).

RESULTS

Comorbidity with neuropsychopathologies was found in 62.2% of the total sample. In the LSD subgroup, ADHD was present in 33%, Anxiety Disorder in 28.8%, Developmental Coordination Disorder in 17.8%, Language Disorder in 11% and Mood Disorder in 9.4% of patients. In LD NOS subgroup, Language Disorder was present in 28.6%, Developmental Coordination Disorder in 27.5%, ADHD in 25.4%, Anxiety Disorder in 16.4%, Mood Disorder in 2.1% of patients. A statistically significant presence was respectively found for Language and Developmental Coordination Disorder comorbidity in LD NOS and for ADHD, mood and anxiety disorder comorbidity in SLD subgroup.

CONCLUSIONS

The different findings emerging in this study suggested to promote further investigations to better define the difference between SLD and LD NOS, in order to improve specific interventions to reduce the long range consequences.