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

Motor and visuospatial processing profile in a cross-conditions study: A comparison between developmental coordination disorder and nonverbal learning disability

BACKGROUND

Neurodevelopmental conditions often exhibit overlapping symptoms, posing challenges for differential diagnosis. Developmental Coordination Disorder (DCD) manifests as fundamental motor impairments, often along with co-occurring visuospatial difficulties. Nonverbal Learning Disorder (NLD) features visuospatial core challenges, with a less consistent characterization of its motor profile. Strikingly, to date no study has directly compared DCD and NLD profiles.

AIMS

The present study aimed to analyze whether DCD and NLD share any characteristics by contrasting their motor and visuospatial performances, comparing them with non-diagnosed (ND) peers.

METHODS AND PROCEDURES

A total of 102 participants (8-16 years; DCD N = 29, NLD N = 29, ND N = 44) completed motor and visuospatial tasks. The groups' performance was compared, and the discriminatory power of the measures administered was analyzed.

OUTCOMES AND RESULTS

Our findings support the substantial motor and visuospatial impairments in DCD and NLD, respectively. Regarding diagnostic efficacy, motor and visuospatial tasks effectively differentiated DCD or NLD from ND, with specificities related to each condition. Balance, and to a lesser extent, Spatial Processing revealed significant predictive power in distinguishing between DCD and NLD.

CONCLUSIONS AND IMPLICATIONS

Our results revealed cross-disorder similarities and highlighted specific hallmarks, corroborating the need of a comprehensive motor and visuospatial assessment for distinguishing between DCD and NLD.

Assessment and analysis of motor-free visual perception abilities among children aged 5-12 years in Xuzhou, China

Motor-free visual perception abilities are important reference indicator for children's literacy skills. In the absence of Chinese norms, this study utilized the motor-free visual perception test-4 (MVPT-4) to assess the visual perception abilities of children aged 5-12 years in Xuzhou, China, to lay the foundation for establishing standardized norms in China. From May to July 2023, a stratified random sampling method was used to conduct MVPT-4 evaluation on 525 kindergarten and primary school children in Xuzhou, China. MVPT-4 raw scores in each age group showed an increasing trend with age, and the differences were statistically significant (P < 0.01). There was no significant difference in raw scores between genders in each age group (P > 0.05). Standard scores in each age group showed no significant difference compared to the American norms (P > 0.05). The results of this study indicated that in the absence of national or regional norms in China, American norms can be used to assess the visual perception abilities of Chinese children. This study provides a reference for clinicians and educators to identify children with potential dyslexia.

Action-outcome Regularity Perceptual Sensitivity in Children with Developmental Coordination Disorder

PURPOSE

An internal model deficit is considered to underlie developmental coordination disorder (DCD); thus, children with DCD have an altered sense of agency (SoA), which is associated with depressive symptoms. Furthermore, the perception of action-outcome regularity is present in early development, is involved in the generation of SoA, and has roles in adaptive motor learning and coordinated motor skills. However, perceptual sensitivity to action-outcome regularity has not been examined in children with DCD.

METHODS

We investigated perceptual sensitivity to action-outcome regularity in 6-15-year-old children with DCD and age- and sex-matched typically developing (TD) children. Both groups were assessed for coordinated motor skills with the Movement Assessment Battery for Children-2nd Edition, while the DCD group was assessed with the DCD Questionnaire, Social Communication Questionnaire, Attention-Deficit/Hyperactivity Disorder-Rating Scale, and Depression Self- Rating Scale for Children.

RESULTS

Perceptual sensitivity to action-outcome regularity was significantly reduced in children with DCD. However, there was a significant correlation between perceptual sensitivity to action-outcome regularity and age in DCD and TD children. Perceptual sensitivity to action-outcome regularity was significantly lower in younger children with DCD than in younger and older TD children, but there were no significant differences between older children with DCD and younger and older TD children.

CONCLUSION

The current results suggest that children with DCD have significantly reduced perceptual sensitivity to action-outcome regularity at younger ages, which may alter SoA and inhibit internal model development, thereby reducing motor skill coordination.

Which outcomes are key to the pre-intervention assessment profile of a child with developmental coordination disorder? A systematic review and meta-analysis

BACKGROUND

Purpose of this study was to determine what key aspects of function should be incorporated to make up a pre-intervention assessment profile of a child with Developmental Coordination Disorder (DCD); more specifically, what aspects of functioning are implicated in DCD and what is their relative impact?

METHODS

A systematic review and meta-analysis were conducted, for which Pubmed, Web of Science, Scopus and Proquest were searched (last update: April 2023, PROSPERO: CRD42023461619). Case-control studies were included to determine point estimates for performances on field-based tests in different domains of functioning. Risk of bias was assessed, and level of evidence estimated. Random-effect meta-analyses were performed to calculate the pooled standardized mean differences for domains of functioning and subgrouping was done for clinically relevant subdomains. Heterogeneity was determined with I2.

RESULTS

121 papers were included for analyses. Data of 5 923 children with DCD were included (59.8% boys) and 23 619 Typically Developing (TD) children (45.8% boys). The mean (SD) age of the DCD group was 10.3y (1.2) and 9.3y (1.3) for the TD children. Moderate evidence was found for motor performance, executive functions, sensory processing and perceptions, cognitive functions and sports and leisure activities to be affected in children with DCD.

CONCLUSION

Differences between the two groups varied per domain of functioning. This emphasizes the diversity present within children with DCD and provides a rationale for explaining the heterogeneity in this patient group. Yet, results highlight the potential involvement of all these domains and call for clinicians to be alert not only to examine motor skill difficulties but also other aspects of function. Results indicate the need to develop an individualized pre-intervention multi-dimensional assessment profile for each child with DCD. It also supports the important role that clinicians play in an interdisciplinary team to tackle the difficulties encountered by children with DCD.

"Picture this from there": spatial perspective-taking in developmental visuospatial disorder and developmental coordination disorder

Introduction

Either Developmental Visuospatial Disorder (DVSD) and Developmental Coordination Disorder (DCD) present with difficulties in visuospatial processing, even though entailing different degrees of impairment. Among the visuospatial domain, spatial perspective taking is essential to interact with the environment and is significantly involved in many daily activities (e.g., environment navigation and spatial orienting). Notwithstanding, no previous studies have investigated this spatial domain in children with DVSD and limited evidence is available regarding DCD. Consistent with a transdiagnostic approach, the first goal of the present study was to compare spatial perspective taking abilities of these groups, also including a control group of not diagnosed peers (ND). Secondly, the role of different fine-motor and visuo-spatial predictors on the spatial perspective taking performance was considered.

Method

A total of 85 participants (DVSD = 26; DCD = 26; ND = 33), aged between 8 and 16 years old, were included in the study. Tasks assessing spatial perspective taking, fine-motor, visual imagery, and mental rotation skills, as well as visuo-spatial working memory were administered.

Results and Discussion

Overall, our results confirmed weaknesses in spatial perspective taking in both clinical groups, with the DVSD obtaining the lowest scores. Similarities and differences in the predictors accounting for the performance in the spatial perspective taking task emerged, suggesting the possible employment of different fine-motor or visuospatial strategies by group. Findings are discussed considering the potential impact they may have both in research and clinical practice.

The effectiveness of a reading and cognitive task-based Web delivered intervention program for children with reading difficulties

The present study aimed to investigate the improvement of reading ability and cognitive performance of children with reading difficulties through a Web application named "Poke the Reading Ability" (PtRA). PtRA is designed to assist the intervention of reading difficulties in Greek, a language that is more transparent than English. Sixty (60) children between nine (9) to twelve (12) years old (mean age 10.18 years). The baseline assessment consisted of two batteries of reading and cognitive abilities tests. Test-A, a Greek standardized psychometric tool and Askisi, a newly developed neuropsychological battery of tests are adopted to assess reading and cognitive performance. Both tools, were used in order to screen children's reading and cognitive performance before and after implementing the PtRA. The PtRA Web intervention consists of (a) tasks that focus on improving visual and auditory working memory, (b) tasks that improve phonological awareness and decoding, (c) tasks that are adopted to strengthen visual discrimination ability and (d) tasks that improve reading comprehension ability. Following the Web delivered intervention program the results revealed that the reading and cognitive abilities of children with reading difficulties were statistically significant improved in all 9 reading and all 3 cognitive abilities tasks.

Motor Skills and Visual Deficits in Developmental Coordination Disorder: A Narrative Review

BACKGROUND

Developmental coordination disorder (DCD) is a developmental disorder in which numerous comorbidities seem to coexist, such as motor and visual impairment and some executive functions; Methods: A narrative review on motor and visual deficits in children with DCD was carried out; Results and Discussion: Fine and gross motor skills are affected in children with DCD. In addition, they seem to be related to visual deficits, such as difficulty in visual perception, sensory processing and visual memory. Limitations have also been found in accommodation. Interventions in children with DCD should be aimed at improving both aspects, since vision affects motor skills and vice versa; Conclusions: In children with DCD, who present a marked deficit in global shape processing, it causes an association between deficiencies in visual perception and motor skills.

ADGRL3, FGF1 and DRD4: Linkage and Association with Working Memory and Perceptual Organization Candidate Endophenotypes in ADHD

Attention deficit hyperactivity disorder (ADHD) is a highly heritable neurobehavioral disorder that affects children worldwide, with detrimental long-term consequences in affected individuals. ADHD-affected patients display visual-motor and visuospatial abilities and skills that depart from those exhibited by non-affected individuals and struggle with perceptual organization, which might partially explain impulsive responses. Endophenotypes (quantifiable or dimensional constructs that are closely related to the root cause of the disease) might provide a more powerful and objective framework for dissecting the underlying neurobiology of ADHD than that of categories offered by the syndromic classification. In here, we explore the potential presence of the linkage and association of single-nucleotide polymorphisms (SNPs), harbored in genes implicated in the etiology of ADHD (ADGRL3, DRD4, and FGF1), with cognitive endophenotypes related to working memory and perceptual organization in 113 nuclear families. These families were ascertained from a geographical area of the Caribbean coast, in the north of Colombia, where the community is characterized by its ethnic diversity and differential gene pool. We found a significant association and linkage of markers ADGRL3-rs1565902, DRD4-rs916457 and FGF1-rs2282794 to neuropsychological tasks outlining working memory and perceptual organization such as performance in the digits forward and backward, arithmetic, similarities, the completion of figures and the assembly of objects. Our results provide strong support to understand ADHD as a combination of working memory and perceptual organization deficits and highlight the importance of the genetic background shaping the neurobiology, clinical complexity, and physiopathology of ADHD. Further, this study supplements new information regarding an ethnically diverse community with a vast African American contribution, where ADHD studies are scarce.

Elementary visuospatial perception deficit in children with neurodevelopmental disorders

AIM

To assess the prevalence of elementary visuospatial perception (EVSP) deficit in children with neurodevelopmental disorders.

METHOD

Using a screening test designed and validated to measure dorsal EVSP ability, 168 children (122 males, 46 females; mean age 10y [SD 1y 10mo], range 4y 8mo-16y 4mo) diagnosed with developmental coordination disorder (DCD), specific learning disorder (SLD), attention-deficit/hyperactivity disorder (ADHD), and/or oral language disorder were compared with a group of 184 typically developing children. We also tested 14 children with binocular vision dysfunction and no neurodevelopmental disorder.

RESULTS

Children with SLD scored below the interquartile range of typically developing children as frequently (59%) as children with DCD, but only 5% were severely impaired (i.e. scored as outliers). Children with DCD were the most severely impaired (22% of outliers), even more so when they exhibited a co-occuring disorder. Children with language disorder and those with binocular vision dysfunction scored similarly to the group of typically developing children.

INTERPRETATION

These results confirm the importance of assessing EVSP in the clinical evaluation of children with neurodevelopmental disorders, in particular those presenting with DCD or SLD. What this paper adds More than half of children with developmental coordination disorder (DCD) scored below the normal interquartile range on the elementary visuospatial perception (EVSP) test. More than half of children with specific learning disorder (SLD) scored below the normal interquartile range on the EVSP test. Twenty-two percent of children with DCD performed as outliers on the EVSP test. Children with language disorder and those with binocular vision dysfunction scored similarly to typically developing children.

Increased visual bias in children with developmental coordination disorder: Evidence from a visual-tactile temporal order judgment task

BACKGROUND

Previous studies have suggested that children with developmental coordination disorder (DCD) rely heavily on vision to perform movements, which may contribute to their clumsy movements. However, few studies have objectively and quantitatively investigated the perceptual biases of children with DCD.

METHODS

A visual-tactile temporal order judgment (TOJ) task was used to measure and compare the perceptual biases of 19 children with DCD and 19 age- and sex-matched typically developing children. The point of subjective equality, which demonstrates when "visual first" and "tactile first" judgment probabilities are equal (50%), obtained by analyzing the results of the visual-tactile TOJ task, was used as an indicator of perceptual biases. Further, variables (age and manual dexterity in all participants; motor function, autism spectrum disorder and attention-deficit hyperactivity disorder traits, and depressive symptoms in children with DCD) associated with perceptual biases were examined with correlation analysis.

RESULTS

Children with DCD had significantly stronger visual bias than typically developing children. Overall correlation analysis showed that increased visual bias was significantly correlated with poor manual dexterity.

CONCLUSION

Children with DCD had a strong visual bias, which was associated with poor manual dexterity.

A research framework to isolate visuospatial from childhood motor coordination phenotypes

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

Exploring the Link between Visual Perception, Visual-Motor Integration, and Reading in Normal Developing and Impaired Children using DTVP-2

Reading is known to be primarily a linguistic task. However, to successfully decode written words, children also need to develop good visual-perception skills. Furthermore, motor skills are implicated in letter recognition and reading acquisition. Three studies have been designed to determine the link between reading, visual perception, and visual-motor integration using the Developmental Test of Visual Perception version 2 (DTVP-2). Study 1 tests how visual perception and visual-motor integration in kindergarten predict reading outcomes in Grade 1, in typical developing children. Study 2 is aimed at finding out if these skills can be seen as clinical markers in dyslexic children (DD). Study 3 determines if visual-motor integration and motor-reduced visual perception can distinguish DD children according to whether they exhibit or not developmental coordination disorder (DCD). Results showed that phonological awareness and visual-motor integration predicted reading outcomes one year later. DTVP-2 demonstrated similarities and differences in visual-motor integration and motor-reduced visual perception between children with DD, DCD, and both of these deficits. DTVP-2 is a suitable tool to investigate links between visual perception, visual-motor integration and reading, and to differentiate cognitive profiles of children with developmental disabilities (i.e. DD, DCD, and comorbid children). Copyright © 2017 John Wiley & Sons, Ltd.

Children with developmental coordination disorder (DCD) can adapt to perceptible and subliminal rhythm changes but are more variable

Children with DCD demonstrate impairments in bimanual finger tapping during self-paced tapping and tapping in synchrony to different frequencies. In this study, we investigated the ability of children with DCD to adapt motorically to perceptible or subliminal changes of the auditory stimuli without a change in frequency, and compared their performance to typically developing controls (TDC). Nineteen children with DCD between ages 6-11years (mean age±SD=114±21months) and 17 TDC (mean age±SD=113±21months) participated in this study. Auditory perceptual threshold was established. Children initially tapped bimanually to an antiphase beat and then to either a perceptible change in rhythm or to gradual subliminal changes in rhythm. Children with DCD were able to perceive changes in rhythm similar to TDC. They were also able to adapt to both perceptible and subliminal changes in rhythms similar to their age- and gender- matched TDC. However, these children were significantly more variable compared with TDC in all phasing conditions. The results suggest that the performance impairments in bilateral tapping are not a result of poor conscious or sub-conscious perception of the auditory cue. The increased motor variability may be associated with cerebellar dysfunction but further behavioral and neurophysiological studies are needed.

Atypical within- and between-hemisphere motor network functional connections in children with developmental coordination disorder and attention-deficit/hyperactivity disorder

Developmental coordination disorder (DCD) and attention-deficit hyperactivity disorder (ADHD) are highly comorbid neurodevelopmental disorders; however, the neural mechanisms of this comorbidity are poorly understood. Previous research has demonstrated that children with DCD and ADHD have altered brain region communication, particularly within the motor network. The structure and function of the motor network in a typically developing brain exhibits hemispheric dominance. It is plausible that functional deficits observed in children with DCD and ADHD are associated with neurodevelopmental alterations in within- and between-hemisphere motor network functional connection strength that disrupt this hemispheric dominance. We used resting-state functional magnetic resonance imaging to examine functional connections of the left and right primary and sensory motor (SM1) cortices in children with DCD, ADHD and DCD + ADHD, relative to typically developing children. Our findings revealed that children with DCD, ADHD and DCD + ADHD exhibit atypical within- and between-hemisphere functional connection strength between SM1 and regions of the basal ganglia, as well as the cerebellum. Our findings further support the assertion that development of atypical motor network connections represents common and distinct neural mechanisms underlying DCD and ADHD. In children with DCD and DCD + ADHD (but not ADHD), a significant correlation was observed between clinical assessment of motor function and the strength of functional connections between right SM1 and anterior cingulate cortex, supplementary motor area, and regions involved in visuospatial processing. This latter finding suggests that behavioral phenotypes associated with atypical motor network development differ between individuals with DCD and those with ADHD.

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Resting-state fMRI was used to examine motor networks of children with DCD and ADHD.

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DCD and ADHD exhibited atypical within- and between-hemisphere motor network connections.

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Neuromuscular development was associated with functional connection strength in DCD, but not ADHD.

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Resting-state fMRI can identify shared and distinct neural mechanisms that underlie ADHD and DCD.

Study of clinical characteristics in young subjects with Developmental coordination disorder

BACKGROUND

Developmental Coordination Disorder (DCD) is a chronic neurological disorder observed in children. DCD is characterized by slowness in activities and motor impairment that affects the children's daily living and academic achievements, and later their professional and social behavior. Our aim in this work was to report characteristics frequencies in a group of children with DCD and to propose a subtyping of DCD characteristics.

METHODS

Thirty three clinical DCD characteristics, the mostly reported in the literature, were assessed in 129 patients, boys and girls aged from 4years to 18years, and their subtyping was proposed. The statistical analyses were carried out with the Chi square, the t-test and the correlation for the statistical differences, and with the Ward clustering method for subtyping.

RESULTS

We found that there were 3.17 boys for one girl, all patients were characterized as slow, 47% were left-handers or ambidextrous, 36% and 26% had orofacial and verbal dyspraxia, respectively, 83% were found anxious, and 84% were described as being clumsy.

CONCLUSIONS

It appears from these results that a child with DCD expresses more than a single difficulty. Three subtypes emerged from the statistical analysis in this study: (1) clumsiness and other characteristics except language difficulties; (2) self-esteem and peer relation without clumsiness and language difficulties; (3) language difficulties and orofacial dyspraxia.

Visual processing in reading disorders and attention-deficit/hyperactivity disorder and its contribution to basic reading ability

Whether visual processing deficits are common in reading disorders (RD), and related to reading ability in general, has been debated for decades. The type of visual processing affected also is debated, although visual discrimination and short-term memory (STM) may be more commonly related to reading ability. Reading disorders are frequently comorbid with ADHD, and children with ADHD often have subclinical reading problems. Hence, children with ADHD were used as a comparison group in this study. ADHD and RD may be dissociated in terms of visual processing. Whereas RD may be associated with deficits in visual discrimination and STM for order, ADHD is associated with deficits in visual-spatial processing. Thus, we hypothesized that children with RD would perform worse than controls and children with ADHD only on a measure of visual discrimination and a measure of visual STM that requires memory for order. We expected all groups would perform comparably on the measure of visual STM that does not require sequential processing. We found children with RD or ADHD were commensurate to controls on measures of visual discrimination and visual STM that do not require sequential processing. In contrast, both RD groups (RD, RD/ADHD) performed worse than controls on the measure of visual STM that requires memory for order, and children with comorbid RD/ADHD performed worse than those with ADHD. In addition, of the three visual measures, only sequential visual STM predicted reading ability. Hence, our findings suggest there is a deficit in visual sequential STM that is specific to RD and is related to basic reading ability. The source of this deficit is worthy of further research, but it may include both reduced memory for order and poorer verbal mediation.

Predicting severe motor impairment in preterm children at age 5 years

OBJECTIVE

To determine whether the ability to predict severe motor impairment at age 5 years improves between birth and 18 months.

DESIGN

Ancillary study of the Caffeine for Apnea of Prematurity Trial.

SETTING AND PATIENTS

International cohort of very low birth weight children who were assessed sequentially from birth to 5 years.

OUTCOME MEASURES

Severe motor impairment was defined as a score <5th percentile on the Movement Assessment Battery of Children (MABC), or inability to complete the MABC because of cerebral palsy. Multivariable logistic regression cumulative risk models used four sets of predictor variables: early neonatal risk factors, risk factors at 36 weeks' postmenstrual age, risk factors at a corrected age of 18 months, and sociodemographic variables. A receiver operating characteristic curve (ROC) was generated for each model, and the four ROC curves were compared to determine if the addition of the new set of predictors significantly increased the area under the curve (AUC).

RESULTS

Of 1469 children, 291 (19.8%) had a severe motor impairment at 5 years. The AUC increased from 0.650 soon after birth, to 0.718 (p<0.001) at 36 weeks' postmenstrual age, and to 0.797 at 18 months (p<0.001). Sociodemographic variables did not significantly improve the AUC (AUC=0.806; p=0.07).

CONCLUSIONS

Prediction of severe motor impairment at 5 years of age using a cumulative risk model improves significantly from birth to 18 months of age in children with birth weights between 500 g and 1250 g.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov number NCT00182312.

[Formula: see text]Parent-report and performance-based measures of executive function assess different constructs

A total of 405 children of 5-18 years of age were administered performance-based and parent-report measures of executive function (EF), and measures of motor, attention, reading, and mathematics performance. Attention, reading, and mathematics abilities were associated with a parent-report measure of EF. Reading and mathematics abilities were also associated with performance-based measures of EF, including the Animal Sorting, Inhibition, and Response Set subtests of the Developmental NEuroPSYchological Assessment-II. In contrast, motor functioning was only associated with performance-based measures of EF. Findings suggest that different constructs of EF are measured by parent-report versus performance-based measures, and that these different constructs of EF are associated with different neurodevelopmental processes.

Efficacy of a perceptual and visual-motor skill intervention program for students with dyslexia

PURPOSE

To verify the efficacy of a perceptual and visual-motor skill intervention program for students with dyslexia.

METHODS

The participants were 20 students from third to fifth grade of a public elementary school in Marília, São Paulo, aged from 8 years to 11 years and 11 months, distributed into the following groups: Group I (GI; 10 students with developmental dyslexia) and Group II (GII; 10 students with good academic performance). A perceptual and visual-motor intervention program was applied, which comprised exercises for visual-motor coordination, visual discrimination, visual memory, visual-spatial relationship, shape constancy, sequential memory, visual figure-ground coordination, and visual closure. In pre- and post-testing situations, both groups were submitted to the Test of Visual-Perceptual Skills (TVPS-3), and the quality of handwriting was analyzed using the Dysgraphia Scale.

RESULTS

The analyzed statistical results showed that both groups of students had dysgraphia in pretesting situation. In visual perceptual skills, GI presented a lower performance compared to GII, as well as in the quality of writing. After undergoing the intervention program, GI increased the average of correct answers in TVPS-3 and improved the quality of handwriting.

CONCLUSION

The developed intervention program proved appropriate for being applied to students with dyslexia, and showed positive effects because it provided improved visual perception skills and quality of writing for students with developmental dyslexia.

Quiet eye training facilitates visuomotor coordination in children with developmental coordination disorder

INTRODUCTION

Quiet eye training (QET) has been shown to be more effective than traditional training (TT) methods for teaching a throw and catch task to typically developing 8-10 yr old children. The current study aimed to apply the technique to children with developmental coordination disorder (DCD).

METHOD

30 children with DCD were randomly allocated into TT or QET intervention groups. The TT group were taught how to control their arm movements during the throw and catch phases, while the QET group were also taught to fixate a target location on the wall prior to the throw (quiet eye1; QE1), followed by tracking the ball prior to the catch (quiet eye2; QE2). Performance, gaze and motion analysis data were collected at pre/post-training and 6-week retention.

RESULTS

The QET group significantly increased QE durations from pre-training to delayed retention (QE1 = +247 ms, QE2 = +19%) whereas the TT group experienced a reduction (QE1 = -74 ms, QE2 = -4%). QET participants showed significant improvement in the quality of their catch attempts and increased elbow flexion at catch compared to the TT group (QET = -28°, TT = -1°).

CONCLUSION

QET changed DCD children's ability to focus on a target on the wall prior to the throw, followed by better anticipation and pursuit tracking on the ball, which in turn led to improved catching technique. QET may be an effective adjunct to traditional instructions, for therapists teaching visuomotor skills to children with DCD.

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.

Functional connectivity of neural motor networks is disrupted in children with developmental coordination disorder and attention-deficit/hyperactivity disorder

Developmental coordination disorder (DCD) and attention deficit/hyperactivity disorder (ADHD) are prevalent childhood disorders that frequently co-occur. Evidence from neuroimaging research suggests that children with these disorders exhibit disruptions in motor circuitry, which could account for the high rate of co-occurrence. The primary objective of this study was to investigate the functional connections of the motor network in children with DCD and/or ADHD compared to typically developing controls, with the aim of identifying common neurophysiological substrates. Resting-state fMRI was performed on seven children with DCD, 21 with ADHD, 18 with DCD + ADHD and 23 controls. Resting-state connectivity of the primary motor cortex was compared between each group and controls, using age as a co-factor. Relative to controls, children with DCD and/or ADHD exhibited similar reductions in functional connectivity between the primary motor cortex and the bilateral inferior frontal gyri, right supramarginal gyrus, angular gyri, insular cortices, amygdala, putamen, and pallidum. In addition, children with DCD and/or ADHD exhibited different age-related patterns of connectivity, compared to controls. These findings suggest that children with DCD and/or ADHD exhibit disruptions in motor circuitry, which may contribute to problems with motor functioning and attention. Our results support the existence of common neurophysiological substrates underlying both motor and attention problems.

Ophthalmic abnormalities in children with developmental coordination disorder

AIM

To explore associations between developmental coordination disorder (DCD) and ophthalmic abnormalities in children aged 7 to 8 years.

METHOD

Cross-sectional analysis of data from the Avon Longitudinal Study of Parents and Children (ALSPAC), a UK birth cohort, was performed. DCD was defined according to DSM-IV criteria. Children with neurological difficulties or IQ less than 70 were excluded. Ophthalmic abnormalities including visual acuity, refraction, and binocular function were assessed using standard tests. Children who achieved less than the 5th centile in the ALSPAC coordination test and either failed the National Curriculum handwriting test, or achieved less than the 10th centile in the Activities of Daily Living scale (ADL) were defined as having severe DCD, while those who scored between the 5th and 15th centiles in the coordination test and either failed the handwriting test, or achieved less than the 15th centile in the ADL were defined as having moderate DCD.

RESULTS

Complete data were available for 7154 children. One hundred and twenty children (1.8%) met the criteria for severe DCD. A further 215 children had moderate DCD. Children with severe DCD were more likely to have the following: abnormal sensory fusion at near (odds ratio [95% confidence interval]) (1.98 [1.13-3.48]) and distance (2.59 [1.16-5.79]) and motor fusion (1.74 [1.07-2.84]); reduced stereoacuity (2.75 [1.78-4.23]); hypermetropia (2.29 [1.1-4.57]) and anisometropia (2.27 [1.13-4.60]). The majority of children found to have both DCD and a refractive error, had been previously prescribed glasses and wore them for the assessments (71%).

INTERPRETATION

Children with severe DCD had abnormalities in binocular vision, refractive error, and ocular alignment. We recommend that children with DCD be assessed for ocular abnormalities as early intervention may improve long-term visual outcome. The impact of untreated ocular abnormalities such as refractive error on the accuracy of the diagnosis of DCD is difficult to ascertain and further work would be of benefit.

Visual-motor perception in students with attention deficit with hyperactivity disorder

PURPOSE

The aim of this study was to characterize and to compare the visual-motor perception of students with Attention Deficit with Hyperactivity Disorder (ADHD) with students with good academic performance.

METHODS

Forty students from 2nd to 5th grades of an elementary public school, male gender (100%), aged between 7 and 10 years and 8 months old participated, divided into: GI (20 students with ADHD) and GII (20 students with good academic performance), paired according to age, schooling and gender with GI. The students were submitted to Developmental Test of Visual Perception (DTVP-2).

RESULTS

The students of GI presented low performance in spatial position and visual closure (reduced motor) and inferior age equivalent in reduced motor perception, when compared to GII.

CONCLUSION

The difficulties in visual-motor perception presented by students of GI cannot be attributed to a primary deficit, but to a secondary phenomenon of inattention that interferes directly in their visual-motor performance.

Fitness limitations in non-disabled extremely low birthweight adolescents

AIM

This study aims to compare non-disabled otherwise healthy extremely low birthweight (ELBW) (<1000 g) children and term-born peers in an investigation of relationship between cardiorespiratory endurance and parent report of competence.

METHODS

Forty-eight of 105 eligible ELBW 11- to 13-year-old children (27 male) and 55 term-born school peers (28 male) completed a 20-m shuttle run, anthropometric measures, respiratory function tests and the Motor Assessment Battery for Children. Parents completed the Child Behavior Checklist (CBCL).

RESULTS

The ELBW group had poorer cardiorespiratory endurance (P = 0.002), growth (P = 0.002), respiratory function (P = 0.003) and motor ability (P < 0.001) than term-born peers. Parents reported the ELBW children to be less competent than term-born peers: CBCL total T score mean difference -9, 95% confidence interval -14, -5 (P < 0.001). Cardiorespiratory endurance predicted competence (regression coefficient 0.865; 95% confidence interval 0.352, 1.378; P = 0.001) independent of prematurity, growth, respiratory function, motor score, gender and socio-economic status. Cardiorespiratory endurance had association with social competence for all participating children, but was related to CBCL Activities Competence only for the ELBW children who were the significantly less fit group.

CONCLUSIONS

The poor cardiorespiratory endurance prevalent in non-disabled otherwise healthy ELBW children is associated with general competence independent of prematurity and of the impact of other mild physical deficits, gender or socio-economic status. The relationship demonstrated between cardiorespiratory endurance and competence to engage in general activities of daily living, seen only in the less fit ELBW children, identifies the fitness levels in non-disabled ELBW children as a barrier to participation.

Childhood clumsiness and peer victimization: a case-control study of psychiatric patients

BACKGROUND

Poor motor and social skills as well as peer victimization are commonly reported in both ADHD and autism spectrum disorder. Positive relationships between poor motor and poor social skills, and between poor social skills and peer victimization, are well documented, but the relationship between poor motor skills and peer victimization has not been studied in psychiatric populations.

METHOD

277 patients (133 males, 144 females), mean age 31 years, investigated for ADHD or autism spectrum disorder in adulthood and with normal intelligence, were interviewed about childhood peer victimization and examined for gross motor skills. The parents completed a comprehensive questionnaire on childhood problems, the Five to Fifteen. The Five to Fifteen is a validated questionnaire with 181 statements that covers various symptoms in childhood across eight different domains, one of them targeting motor skills. Regression models were used to evaluate the relationship between motor skills and the risk and duration of peer victimization, adjusted for sex and diagnosis.

RESULTS

Victims were described as more clumsy in childhood than their non-victimized counterparts. A significant independent association was found between reportedly poor childhood gross motor skills and peer victimization (adjusted odds ratio: 2.97 [95% confidence interval: 1.46-6.07], n = 235, p = 0.003). In adulthood, the victimized group performed worse on vertical jumps, a gross motor task, and were lonelier. Other factors that were expected to be associated with peer victimization were not found in this highly selected group.

CONCLUSION

Poor gross motor skills constitute a strong and independent risk factor for peer victimization in childhood, regardless of sex, childhood psychiatric care and diagnosis.

Everyday memory in children with developmental coordination disorder

Children with developmental coordination disorder (DCD) have deficits in working memory, but little is known about the everyday memory of these children in real-life situations. We investigated the everyday memory function in children with DCD, and explored the specific profile of everyday memory across different domains. Nineteen children with DCD and 19 typically developing (TD) children participated in the study. Their everyday memory performance was evaluated using the Rivermead Behavioral Memory Test for Children, which showed that 52.6% of the children with DCD had everyday memory deficits. The overall everyday memory scores of the DCD group were significantly lower than those of the controls, particularly in the verbal and visual memory domains. Pearson correlation analysis indicated significant associations between verbal intelligence and memory scores. Analysis of covariance with verbal intelligence as a covariate showed no significant differences between groups in memory scores. Mediator analysis supported the notion that everyday memory deficits in children with DCD were fully mediated through verbal intelligence. We provide evidence of everyday memory deficits in most of the children with DCD, and hypothesize that language abilities are their underlying cause. The clinical implications of these findings and recommendations for additional research are discussed.

Motor skills of children newly diagnosed with Attention Deficit Hyperactivity Disorder prior to and following treatment with stimulant medication

Motor difficulties are common in children with Attention Deficit Hyperactivity Disorder (ADHD). Although preliminary evidence has suggested that methylphenidate can improve the motor skills in children with ADHD and Developmental Coordination Disorder (DCD), the effect of stimulant medication on motor performance in children newly diagnosed with ADHD with or without motor impairment remains unclear. A cohort study of 49 medication-naïve children (39 male; mean age 8.4±1.3 years) with ADHD was conducted. Children were evaluated using the Movement Assessment Battery for Children and the developmental test of visual motor integration at diagnosis and again three months following daily treatment with a stimulant medication. Motor difficulties were highly present at baseline (73.5%) but resolved in a subset after treatment with stimulant medication, suggesting that their motor difficulties may be attributed in part to their attentional problems. Nevertheless, motor impairment persisted in 55.1% of the sample. The severity of the behavioural symptoms was significantly associated with balance skills in children without motor impairments (r(2)=0.30, p<0.01) and with visual motor integration skills in children with persisting motor difficulties (r(2)=0.27, p<0.01). Attentional difficulties negatively affect the motor skills of children with ADHD. Following the use of stimulant medication, an important subset continued to demonstrate motor difficulties. The improvement in behaviour was insufficient to resolve motor problems and these children should therefore be targeted for rehabilitation services.

Comorbid ADHD and DCD: examining cognitive functions using the WISC-IV

This study explored the cognitive performance of children with Attention Deficit/Hyperactivity Disorder (ADHD) and/or Developmental Coordination Disorder (DCD) using the Wechsler Intelligence Scale for Children-IV. Participants were 62 children with ages between 9 years 8 months and 12 years 7 months. These children were placed into one of the four groups: Comparison (n=26), ADHD (n=14), DCD (n=11), and ADHD+DCD (n=11) groups. The ADHD symptoms were assessed using the Australian Disruptive Behaviours Scale, and motor ability was assessed using the McCarron Assessment of Neuromuscular Development (MAND). Significantly poorer perceptual reasoning ability was seen in DCD and ADHD+DCD groups but not in the ADHD group. The findings provide evidence that a deficit in visuo-spatial ability may underlie DCD but not ADHD. These findings revealed different cognitive profiles for ADHD and/or DCD, thus the current study does not lend support to the common aetiology hypothesis in understanding the basis of ADHD and DCD comorbidity.

Assessment of developmental coordination disorder in children born with extremely low birth weights

There is no tool that is considered the "gold" standard for identifying children with developmental coordination disorder (DCD) and various techniques have been reported in the research literature. The aim of this study was to examine the prevalence of DCD in a cohort of extremely low birth weight (ELBW; birth weight ≤ 1,000g) children at age 5 years using various methods including standardized motor assessment measures, an established clinic protocol, and a parent report. We also examined the association between selected neonatal risk factors and severity of the motor impairment. Four methods were used to assess motor functioning: (1) the Movement Assessment Battery for Children (Movement ABC); (2) a motor assessment battery, which included the Movement ABC, the Beery-Buktenica Developmental Test of Visual Motor Integration, and the Developmental Test of Visual Perception-2; (3) a Perinatal Follow-up Clinic protocol, which included the Geometric Design and the Mazes subtests of the Wechsler Preschool and Primary Scale of Intelligence-Revised, the Fine and Gross Motor subscales of the Child Development Inventory, and a pediatric neuromotor exam; and (4) a parent completed questionnaire (i.e., Developmental Coordination Disorder Questionnaire (DCDQ)). The prevalence of motor impairment in ELBW children was 64% on the Movement ABC, 67% on the motor assessment battery, 66% on the Perinatal Follow-up Clinic protocol, and 26% on the DCDQ. Sensitivity ranged from 36% to 100% and specificity from 65% to 92% using the Movement ABC as the reference standard. Neonatal risk factors associated with increased severity of motor impairment were bronchopulmonary dysplasia, postnatal steroids, and increasing gestational age. Children with birth weights ≤ 1,000 g are at considerable risk for motor impairment; therefore, developmental evaluations should include an assessment of motor functions. A standardized motor assessment test such as the Movement ABC appears to be the most effective and efficient means of identifying motor impairment in this high-risk population.

Risk factor frequency for learning disabilities in low socioeconomic level preschool children in Mexico city

The objective was to identify the frequency of risk factors for Learning Disabilities (LD) in low socioeconomic level children in Mexico City. We studied children by means of: Wechsler, Bender-Gestalt, and Human drawing tests. Average age of male subjects was 5.6±0.9 years, while that of the female group was 5.4±0.5 years. In male subjects, average Total intelligence quotient (T-IQ) score was 98±12.2 while, in the female group, this was 99±12.2. On the Bender-Gestalt test, male subjects had a mental and visual-motor average age of <1 year under chronological age. Female subjects had a mental and visual-motor age 8-7 months under the norm. On the Human drawing test, in male and female subjects, the most frequent at-risk features comprised: self-isolation in 25% of subjects, shyness in 22.4%, and poor internal controls in 22%. In conclusion, we found a high at-risk factor frequency for LD in children of low socioeconomic strata. We highlight the importance of screening children before they attain school age.

Função motora fina de escolares com dislexia, distúrbio e dificuldades de aprendizagem

TEMA: função motora fina em escolares com dislexia, distúrbio e dificuldades de aprendizagem. OBJETIVO: este estudo teve por objetivo caracterizar o desempenho da função motora fina, sensorial e perceptiva em escolares com dislexia, distúrbio e dificuldades de aprendizagem e correlacionar estes achados à escrita destes escolares. MÉTODO: participaram deste estudo 80 escolares da 2ª à 4ª série do ensino fundamental, na faixa etária de 7 a 12 anos de idade, de ambos os gêneros, distribuídos em: GI: formado por 20 escolares com dislexia, GII: formado por 20 escolares com distúrbio de aprendizagem, GIII: formado por 20 escolares com dificuldades de aprendizagem e GIV: formado por 20 escolares sem dificuldades de aprendizagem. Os escolares foram submetidos à avaliação da função motora fina, sensorial e perceptiva e análise da escrita por meio da escala de disgrafia. RESULTADOS: os resultados evidenciaram que a maioria dos grupos apresentou desempenho inferior nas provas de FMF7 (oposição de dedos), S8 (grafoestesia) e P1 (imitar posturas). Os GI e GII foram os grupos que apresentaram desempenho inferior na maioria das provas em relação aos GIII e GIV. Quanto à grafia, observou-se que no GII todos os escolares são disgráficos. CONCLUSÃO: a presença de alterações motora fina, sensorial e perceptiva é característica de escolares com distúrbio de aprendizagem e dislexia, entretanto esta característica pode ou não ser encontrada nos escolares com dificuldades de aprendizagem, sendo, portanto, esta alteração responsável pelo comportamento disgráfico dos escolares com transtornos de aprendizagem deste estudo.

Effects of dyslexia on postural control in adults

Dyslexia has been shown to affect postural control. The aim of the present study was to investigate the difference in postural stability measured as torque variance in an adult dyslexic group (n=14, determined using the Adult Dyslexia Checklist (ADCL) and nonsense word repetition test) and an adult non-dyslexic group (n=39) on a firm surface and on a foam block and with eyes open and eyes closed. Another aim was to investigate the correlation between ADCL scores and postural stability. Findings showed that ADCL scores correlated with torque variance in the anteroposterior direction on foam with eyes closed (p=0.001) and in the lateral direction on the foam surface with eyes closed (p=0.040) and open (p=0.010). General Linear Model analysis showed that high dyslexia scores were associated with increased torque variance (p<0.001). However, we found no significant difference between dyslexics and non-dyslexics, though there were indications of larger torque variance in the dyslexics. The findings suggest that adults with high dyslexic ADCL scores may experience sub-clinical balance deficits. Hence, assessing motor ability and postural control in those with high ADCL scores is motivated.

Can the Child Behavior Checklist be used to screen for motor impairment?

AIM

It has been suggested that one approach to identifying motor impairment in children is to use the Child Behavior Checklist (CBCL) as a screening tool. The current study examined the validity of the CBCL in identifying motor impairment.

METHOD

A total of 398 children, 206 females and 192 males, aged from 3 years 9 months to 14 years 10 months were assessed on the McCarron Assessment of Neuromuscular Development to determine their motor ability. Parents completed the CBCL.

RESULTS

The 'Clumsy' item on the CBCL was found to predict motor ability independent of the child's age, sex, and scores on other items of the CBCL. However, the sensitivity of the 'Clumsy' item in terms of identifying motor impairment was found to be a low 16.7% compared with specificity of 93.2%. The item 'Not liked' was also found to be a significant predictor of motor impairment.

INTERPRETATION

Although the 'Clumsy' and 'Not liked' items were found to have a relationship with motor ability, they should not be relied upon to categorize children as motor impaired versus not impaired. It is possible that these items may be better indicators of motor impairment in children with developmental disorders such as attention-deficit-hyperactivity disorder, but clinical samples are needed to address this.

Different behavioral and eye movement patterns of dyslexic readers with and without attentional deficits during single word reading

Comorbidity of learning disabilities is a very common phenomenon which is intensively studied in genetics, neuropsychology, prevalence studies and causal deficit research. In studies on the behavioral manifestation of learning disabilities, however, comorbidity is often neglected. In the present study, we systematically examined the reading behavior of German-speaking children with dyslexia, of children with attentional problems, of children with comorbid dyslexia and attentional problems and of normally developing children by measuring their reading accuracy, naming latencies and eye movement patterns during single word reading. We manipulated word difficulty by contrasting (1) short vs. long words with (2) either low or high sublexical complexity (indexed by consonant cluster density). Children with dyslexia only (DYS) showed the expected reading fluency impairment of poor readers in regular orthographies but no accuracy problem. In contrast, comorbid children (DYS+AD) had significantly higher error rates than all other groups, but less of a problem with reading fluency than DYS. Concurrently recorded eye movement measures revealed that DYS made the highest number of fixations, but exhibited shorter mean single fixations than DYS+AD. Word length had the strongest effect on dyslexic children, whereas consonant cluster density affected all groups equally. Theoretical implications of these behavioral and eye movement patterns are discussed and the necessity for controlling for comorbid attentional deficits in children with reading deficits is highlighted.

Dyslexia and developmental co-ordination disorder in further and higher education-similarities and differences. Does the 'label' influence the support given?

Developmental co-ordination disorder (DCD) is a developmental disorder affecting motor co-ordination. The Diagnostics Statistics Manual-IV classification for DCD describes difficulties across a range of activities of daily living, impacting on everyday skills and academic performance in school. Recent evidence has shown that difficulties persist into adulthood. As a consequence, increasing numbers of students are arriving at university and colleges in the UK with a diagnosis of DCD and requesting Disabled Students' Allowance (DSA) to gain support. This preliminary study examined a cohort of 115 students currently in further or higher education in order to compare and contrast similarities and differences in three subgroups: those with a diagnosis of DCD, a second group with DCD and dyslexia and a third group with dyslexia only. It examines how students were supported in the past and now as students. Additionally it identifies differences in reported strengths and difficulties. A higher percentage of those with dyslexia receive DSA. All students have similar types of support not dependent on their diagnosis. The DCD only group lives at home with parents more and has a significantly greater reported motor and executive functioning difficulty than the other two groups.