Reprint of "Deficits of hot executive function in developmental coordination disorder: Sensitivity to positive social cues"

Far Transfer Effects of Trainings on Executive Functions in Neurodevelopmental Disorders: A Systematic Review and Metanalysis

Executive Functions are a set of interrelated, top-down processes essential for adaptive goal-directed behaviour, frequently impaired across different neurodevelopmental disorders with variable degrees of severity. Many executive-function-training studies in children with neurodevelopmental disorders have focused on near effects, investigating post-treatment improvements on directly trained processes, while enhancements of skills not directly trained, defined as far effects, are less considered, albeit these could be extremely relevant for reducing the negative impact of a disorder's core symptomatology. This systematic review and metanalysis aims to investigate the far effect outcomes after EF training in children with different types of neurodevelopmental disorders. 17 studies met the inclusion criteria for the systematic review, while 15 studies were selected in the metanalysis. An overall statistically significant effect size was found in the majority of far effect outcome measures considered in the studies. In particular, trainings on executive functions determine significant far effects on daily life functioning (0.46, 95% CI: [0.05-0.87]) and clinical symptoms (0.33, 95% CI: [0.15-0.51]). Despite a high variability of the results, intensity, frequency and the laboratory/life contexts dimension seem to be the most influential variables in determining far effects. This systematic review and metanalysis highlights the need to measure far effects of executive function training in neurodevelopmental disorders, selecting treatments not only on directly targeted processes, but also according to far impacts on the functional weakness of the disorder.

Efficacy of a Task-Oriented Intervention for Children with a Dual Diagnosis of Specific Learning Disabilities and Developmental Coordination Disorder: A Pilot Study

Background: Task-oriented approaches are recommended for children with developmental coordination disorder (DCD) to address deficits in motor performance and reduce activity limitations. Although this approach is used in several settings, the efficacy of these approaches in children with in dual-diagnosis of specific learning disabilities (SLD) and DCD is less widely known. This study aims to determine the effect of a group-based intervention based on neuromotor task training (NTT) principles on the motor performance of children aged 6–10 years with SLD/DCD. Methods: A pre-post-test controlled study design was conducted in children with a primary diagnosis of specific learning disabilities (SLD). DCD status was confirmed based on clinical assessment. Children scoring ≤16th percentile on the Motor Assessment Battery for Children 2nd Edition (MABC-2), who also presented with a functional motor problem, according to the MABC checklist were considered as having DCD. Children were allocated to the NTT intervention group based on teachers’ perceived notion of need and received two 45–60 min training sessions per week for nine weeks. Children allocated to the usual care (UC) group, received their planned occupational therapy and physical education. The MABC-2 was used to assess changes in motor performance. Outcome and Results: Our numbers confirm that it is crucial to identify the presence of motor coordination difficulties in children who have been diagnosed with SLD. A task-oriented training program based on NTT principles, presented in small groups, has a positive effect on the motor performance in learners with neurodevelopmental disorders and this effect was larger than in the usual care group. Conclusion and Implications: Although using a small group format in children with multiple neurodevelopmental disorders may be challenging for the therapists, it may be a way of delivering services to children in schools for special education. What this paper adds: Children with DCD plus LSD show improvement in their motor skills by performing group-based NTT in the school environment. Group-based NTT shows a significant improvement in the TSS score of the MABC-2 compared to usual care. Children with DCD plus SLD show equal effect sizes after NTT intervention as DCD without SLD.

Reduced Nogo-P3 in adults with developmental coordination disorder (DCD)

Nogo-N2 is associated with the premotor cognitive process that precedes motor response (e.g., conflict monitoring), whereas Nogo-P3 is related to the inhibition of the actual motor response. We examined the influence of motor clumsiness of developmental coordination disorder (DCD) on components of the event-related potential in a Go/Nogo task. Participants were healthy adults (N = 81) that were classified into control and DCD groups based on the Movement Assessment Battery for Children Second Edition. We manipulated the difficulty in stopping a response by varying the frequency of Nogo stimuli in a response task into rare (20%) and frequent (80%) conditions, and Nogo-N2 and Nogo-P3 were calculated from electroencephalograms (EEGs) during the Go/Nogo tasks. The commission error rate in the rare condition was significantly higher in the DCD group than in the control group, indicating that motor clumsiness decreases task performance. There were no differences in Nogo-N2 between DCD and control groups. However, Nogo-P3 in the rare condition was reduced in the DCD group compared to the control group. These results suggest that the influence of motor clumsiness is limited to the cognitive process after the initiation of the actual motor response.

Self-efficacy profile in daily activities: Children at risk and with developmental coordination disorder

AIM

The objectives of this study were: 1) to compare the perceptions of self-efficacy in the daily activities (self-care, schoolwork, and leisure) of boys and girls with DCD, or in children at risk for DCD (r-DCD) and in typical children (TD); 2) to investigate if a self-efficacy assessment could be a support tool in the establishment of children with the DCD profile.

METHODS

Children between 6 to 8 years old (N=115: 35 with DCD, 40 with r-DCD, 40 with TD) were assessed using the Movement Assessment Battery for Children (MABC-2) and the Perceived Efficacy and Goal Setting System (PEGS). A two-way MANOVA showed significant effect for the perceived self-efficacy group.

RESULTS

The Bonferroni post hoc test indicated that in the self-care, schoolwork, leisure, and general self-efficacy dimensions the children with DCD presented significantly lower scores compared to children with r-DCD and TD (p < 0.001). A similar result was observed for r-DCD children in comparison with TD (p < 0.001). The discriminate analysis showed that perceived self-efficacy in leisure activities was the variable that most contributed to the discrimination of the groups.

CONCLUSION

The judgment of children with DCD and r-DCD on the effectiveness of the execution of schoolwork and leisure activities may have been influenced by the motor skill difficulties showed by the children.

The Naturalness of Biological Movement by Individuals with Autism Spectrum Conditions: Taking Neurotypical Individuals' Viewpoint

BACKGROUND:

When an action is being observed, it is matched to the observer’s internal representation of the action. The more similar, the more the action is perceived as natural. A factor influencing judgement of naturalness is the kinematic features of a movement. However, these features could be altered due to certain conditions that can modify movement such as Autism Spectrum Disorders. As a result, neurotypical observers may fail to interpret the action due to impaired naturalness.

AIM:

This work aims to investigate (1) whether neurotypical observers judge the autistic individuals’ movement as less natural, (2) which kinematic factors (jerk, acceleration, velocity and size) contribute to their perception and (3) whether cue reliance correlates with autistic traits.

METHODS:

Thirty neurotypical participants (20 – 33 years old; 15 males) completed autistic trait screening questionnaires (ADC, TAS-20, AQ). They completed a computer task showing 2D side-to-side arm movements recorded from neurotypical and autistic individuals. Finally, they rated the naturalness of the observed movements, and how certain they were with their answer.

RESULTS:

There was a significant difference between the participants’ perception of naturalness of the two movement groups. Jerk, acceleration and velocity contributed to shaping the participants’ perception with a jerk as the most significant factor. The correlation between the participants’ autistic trait and both their perception of naturalness as well as of each kinematic cue were not significant.

CONCLUSION:

Our neurotypical participants perceived the autistic movements as less natural. Their perceptions were influenced mainly by the jerk as well as acceleration and velocity of the autistic movements. Autistic traits in the participants did not correlate to their perception of movement naturalness nor to any of the kinematic factors.

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

Introduction

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

Method

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

Results

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

Conclusion

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

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.

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

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