Cognitive Control of Saccadic Eye Movements in Children with Developmental Coordination Disorder

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.

Behavioral and Neuroimaging Research on Developmental Coordination Disorder (DCD): A Combined Systematic Review and Meta-Analysis of Recent Findings

AIM

The neurocognitive basis of Developmental Coordination Disorder (DCD; or motor clumsiness) remains an issue of continued debate. This combined systematic review and meta-analysis provides a synthesis of recent experimental studies on the motor control, cognitive, and neural underpinnings of DCD.

METHODS

The review included all published work conducted since September 2016 and up to April 2021. One-hundred papers with a DCD-Control comparison were included, with 1,374 effect sizes entered into a multi-level meta-analysis.

RESULTS

The most profound deficits were shown in: voluntary gaze control during movement; cognitive-motor integration; practice-/context-dependent motor learning; internal modeling; more variable movement kinematics/kinetics; larger safety margins when locomoting, and atypical neural structure and function across sensori-motor and prefrontal regions.

INTERPRETATION

Taken together, these results on DCD suggest fundamental deficits in visual-motor mapping and cognitive-motor integration, and abnormal maturation of motor networks, but also areas of pragmatic compensation for motor control deficits. Implications for current theory, future research, and evidence-based practice are discussed.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, identifier: CRD42020185444.

Attentional and executive functions in children and adolescents with developmental coordination disorder and the influence of comorbid disorders: A systematic review of the literature

Developmental coordination disorder (DCD) is a neurodevelopmental disorder affecting primarily motor skills, but attentional and executive impairments are common in affected individuals. Moreover, the presence of neurodevelopmental comorbidities is frequent in this population, which certainly influences the cognitive profile of the children concerned. Previous studies have reported deficits in visuospatial/nonverbal and planning tasks. This systematic review of the literature aims to determine if impairments can be found in other attentional and executive functions as well. The type of cognitive tasks, the tasks’ modality (verbal/nonverbal), and the influence of comorbid disorders on attentional and executive profiles are systematically considered. Forty-one studies were identified through the PubMed/Medline and PsycINFO databases according to pre-established eligibility criteria. The results reveal weaknesses in inhibitory control, working memory, planning, nonverbal fluency, and general executive functioning in children with DCD. The presence of comorbid disorders seemingly contributes to the verbal working memory difficulties findings. This review contributes to a better understanding of the cognitive impairments in DCD and of the needs of children with this disorder, allowing to optimize practitioners’ therapeutic interventions.

Effect of comorbid developmental dyslexia on oculomotor behavior in children with developmental coordination disorder: A study with the Developmental Eye Movement test

Studies have suggested a dysfunction in oculomotor skills in children with developmental coordination disorder (DCD). It has been proposed that the Developmental Eye Movement (DEM) test is useful in testing the dyslexics' (DD) oculomotor behavior during reading, in a simple and indirect manner. The present study aimed at exploring the oculomotor behavior in children with DCD as assessed with the DEM test. We thus compared children with DCD to children with DD and to children with both DCD and DD in order to investigate the specificity of the oculomotor difficulties, as measured by the DEM test. Results showed that 1) children with DCD presented mild atypical performance at the DEM test (error z-score only), 2) children with DD presented particularly poor performance at the DEM test, and 3) the co-morbid condition (DCD + DD) did not add to the severity of atypical performance at the DEM test. In sum, children with DCD were the less affected according to the DEM test, and children with DD (isolated or comorbid) presented the most atypical performance. Results at the DEM test did not allow to highlight clear oculomotor atypicalities in DCD. We thus concluded that more research using eye-tracking techniques is needed to explore the nature of oculomotor atypicalities in DCD children, to distinguish DD and DCD oculomotor behavior, and to understand the profile of children with dual diagnosis.

An exploratory study of gaze behaviour in young adults with developmental coordination disorder

Developmental Coordination Disorder (DCD) is characterized by substantial difficulties with motor coordination to the extent that it has a clear impact on the daily functioning of those who suffer from the disorder. Laboratory-based research indicated impaired oculomotor control in individuals with DCD. However, it is not clear how these oculomotor problems contribute to control and coordination in daily tasks. This study explored differences and similarities in gaze behaviour during reading and cup stacking between young adults with DCD and their matched typically developing counterparts (TD; aged 20-23 years). Gaze behaviour was recorded using eye-tracking, and hand movements were registered using a digital camera. Results of the reading tasks demonstrated similar behaviour between the groups, apart from a lower number of characters recorded per fixation in the DCD group. In cup stacking, the individuals with DCD were slower than their counterparts when three cups had to be displaced to a central target using the dominant hand. The gaze strategy of individuals with DCD involved systematic fixations on the cup or target prior to the hand movement to that cup or target, whereas these alternating saccades between cup and target were less obvious in the TD group. In the bimanual stacking task, where a pyramid of six cups had to be built on a central target using both hands, both groups mainly fixated the central target for the whole duration of the task, without distinct differences in gaze behaviour and duration of performance between individuals with and those without DCD. In conclusion, gaze behaviour of young adults with DCD shows differences from that of their typically developing counterparts that may be related to underlying oculomotor deficits in some but not all daily tasks.

Effect of language proficiency on proactive occulo-motor control among bilinguals

We examined the effect of language proficiency on the status and dynamics of proactive inhibitory control in an occulo-motor cued go-no-go task. The first experiment was designed to demonstrate the effect of second language proficiency on proactive inhibitory cost and adjustments in control by evaluating previous trial effects. This was achieved by introducing uncertainty about the upcoming event (go or no-go stimulus). High- and low- proficiency Hindi-English bilingual adults participated in the study. Saccadic latencies and errors were taken as the measures of performance. The results demonstrate a significantly lower proactive inhibitory cost and better up-regulation of proactive control under uncertainty among high- proficiency bilinguals. An analysis based on previous trial effects suggests that high- proficiency bilinguals were found to be better at releasing inhibition and adjustments in control, in an ongoing response activity in the case of uncertainty. To further understand the dynamics of proactive inhibitory control as a function of proficiency, the second experiment was designed to test the default versus temporary state hypothesis of proactive inhibitory control. Certain manipulations were introduced in the cued go-no-go task in order to make the upcoming go or no-go trial difficult to predict, which increased the demands on the implementation and maintenance of proactive control. High- proficiency bilinguals were found to rely on a default state of proactive inhibitory control whereas low- proficiency bilinguals were found to rely on temporary/transient proactive inhibition. Language proficiency, as one of the measures of bilingualism, was found to influence proactive inhibitory control and appears to modulate the dynamics of proactive inhibitory control.

Comparing Attention to Socially-Relevant Stimuli in Autism Spectrum Disorder and Developmental Coordination Disorder

Difficulties with social interaction have been reported in both children with an autism spectrum disorder (ASD) and children with developmental coordination disorder (DCD), although these disorders have very different diagnostic characteristics. To date, assessment of social skills in a DCD population has been limited to paper-based assessment or parent report. The present study employed eye tracking methodology to examine how children attend to socially-relevant stimuli, comparing 28 children with DCD, 28 children with ASD and 26 typically-developing (TD) age-matched controls (aged 7-10). Eye movements were recorded while children viewed 30 images, half of which were classed as 'Individual' (one person in the scene, direct gaze) and the other half were 'Social' (more naturalistic scenes showing an interaction). Children with ASD spent significantly less time looking at the face/eye regions in the images than TD children, but children with DCD performed between the ASD and TD groups in this respect. Children with DCD demonstrated a reduced tendency to follow gaze, in comparison to the ASD group. Our findings confirm that social atypicalities are present in both ASD and to a lesser extent DCD, but follow a different pattern. Future research would benefit from considering the developmental nature of the observed findings and their implications for support.