Postural sway and perception of affordances in children at risk for developmental coordination disorder

Perception of Affordances for Vertical and Horizontal Jumping in Children: Gymnasts Versus Non-Athletes

Purpose: We investigated the perception of affordances for vertical jumping-and-reaching and horizontal jumping by children. Method: In the horizontal task, children were asked to judge their ability in the standing long jump. In the vertical task, children were asked to judge the height of a ball that they could run to, jump up, and reach with their fingertips. Following judgments, children performed both types of jumps. We compared gymnasts (children with at least 2 years of gymnastics training; 7.92 ± 0.91 years) versus children with no competitive athletic experience (7.74 ± 0.86 years). Results: As expected, actual ability was greater in gymnasts than in non-athletes, for both types of jump (each p < .001). We separately analyzed Constant Error and Absolute Error of judgments (relative to actual performance). Results revealed that gymnasts tended toward underestimation, while non-athletes tended toward overestimation. Absolute error differed between tasks for the non-athletes (p < .001), but for the gymnasts the difference between conditions was not significant (p = .25). Absolute error differed between groups for vertical jump-and-reach (p < .01) but not for horizonal jump (p = .17). Conclusions: Gymnastics experience was associated with a generalized tendency for children to underestimate their jumping ability. In addition, gymnastics experience was associated with judgment accuracy that was consistent across tasks. The results reveal that gymnastics training is associated with changes in athletic ability, but also with changes in the perception of affordances.

Balance control in individuals with developmental coordination disorder: A systematic review and meta-analysis

BACKGROUND

Although it is recognized that the majority of children with developmental coordination disorder (DCD) have balance deficits, comprehensive insights into which balance domains are affected, are still lacking in literature.

RESEARCH QUESTION

To what extent is balance control deficient in individuals with DCD compared to controls?

METHODS

Pubmed, Scopus and Web of Science were systematically searched. Risk of bias was assessed with the Scottish Intercollegiate Guidelines Network checklist for case-control studies. Mean and standard deviations characterizing balance control were extracted to calculate standardized mean differences (SMD) and pooled, if possible, using Review Manager.

RESULTS

The results of 31 studies (1152 individuals with DCD, 1103 typically developing (TD) peers, mean age 10.4 years old) were extracted of which 17 were used for meta-analysis. The mean SMD for the balance subscale of the Movement Assessment Battery for Children was 1.63 (pooled 95 %CI =[1.30;1.97]), indicating children with DCD to perform significantly poorer than their TD peers. Force plate studies also revealed that children with DCD present with a larger sway path during bipedal stance with eyes closed (pooled mean SMD = 0.55; 95 %CI=[0.32;0.78]). Children with DCD tend to have direction-specific limited stability limits and task-independent delayed onset of anticipatory postural adjustments.

INTERPRETATION

Children with DCD perform poorer on different domains of balance compared to TD peers. Future research should focus on comprehensive balance assessment in these children, preferably using a longitudinal design.

Development of affordance perception and recalibration in children and adults

Changes in the body over developmental time (e.g., physical growth) as well as over shorter timescales (e.g., wearing a backpack, carrying a large object) alter possibilities for motor action. How well can children recalibrate their perception of action possibilities to account for sudden changes to body size? The current study compared younger children (4-7 years), older children (8-11 years), and adults as they decided whether they could squeeze through doorways of varying widths. To test for age-related changes in recalibration to modified abilities versus perception of unmodified abilities, half of the participants wore a backpack while making judgments and squeezing through doorways and half did not. Results indicated that judgment accuracy improved with age but that participants had more difficulty when recalibrating to modified abilities. Bias in decision making also changed with age; whereas younger children made riskier decisions by attempting to fit through impossibly small doorways, older children were more cautious. Some particularly cautious participants never generated practice feedback by attempting (and failing) to fit through smaller doorways, which prevented them from recalibrating. Taken together with previous literature, the results of the current study suggest that the development of perception for unmodified versus modified ability proceeds at different rates and depends on the particular motor task.

Cognitive and neuroimaging findings in developmental coordination disorder: new insights from a systematic review of recent research

AIM

To better understand the neural and performance factors that may underlie developmental coordination disorder (DCD), and implications for a multi-component account.

METHOD

A systematic review of the experimental literature published between June 2011 and September 2016 was conducted using a modified PICOS (population, intervention, comparison, outcomes, and study type) framework. A total of 106 studies were included.

RESULTS

Behavioural data from 91 studies showed a broad cluster of deficits in the anticipatory control of movement, basic processes of motor learning, and cognitive control. Importantly, however, performance issues in DCD were often shown to be moderated by task type and difficulty. As well, we saw new evidence of compensatory processes and strategies in several studies. Neuroimaging data (15 studies, including electroencephalography) showed reduced cortical thickness in the right medial orbitofrontal cortex and altered brain activation patterns across functional networks involving prefrontal, parietal, and cerebellar regions in children with DCD than those in comparison groups. Data from diffusion-weighted magnetic resonance imaging suggested reduced white matter organization involving sensorimotor structures and altered structural connectivity across the whole brain network.

INTERPRETATION

Taken together, results support the hypothesis that children with DCD show differences in brain structure and function compared with typically developing children. Behaviourally, these differences may affect anticipatory planning and reduce automatization of movement skill, prompting greater reliance on slower feedback-based control and compensatory strategies. Implications for future research, theory development, and clinical practice are discussed.

Navigating through apertures: perceptual judgements and actions of children with Developmental Coordination Disorder

Passing through a narrow gap/aperture involves a perceptual judgement regarding the size of the gap and an action to pass through. Children with DCD are known to have difficulties with perceptual judgements in near space but whether this extends to far space is unknown. Furthermore, in a recent study it was found that adults with DCD do not scale movements when walking through an aperture in the same way as their peers. The current study, therefore, considered perceptual judgements and motor behaviour of children with DCD while looking at or walking through apertures. Twenty‐nine children with DCD and 29 typically developing (TD) children took part. In Experiment 1, participants completed a perceptual task, where they made passability judgements. Children with DCD showed a significantly smaller critical ratio (aperture size at which a participant first rotates the shoulders to pass through) compared to their TD peers. In Experiment 2, participants completed an action task where they walked through the same apertures. Children with DCD showed a significantly larger critical ratio than TD peers when body size alone was accounted for. Taken together these results suggest that perception within a static context is different from that within a dynamic context for children with DCD. However, despite this difference we have demonstrated a clear relationship between perception and action in children with DCD. A video abstract of this article can be viewed at: https://youtu.be/SABXFrAJtF8

Effects of light touch on postural sway and visual search accuracy: A test of functional integration and resource competition hypotheses

People often multi-task in their daily life. However, the mechanisms for the interaction between simultaneous postural and non-postural tasks have been controversial over the years. The present study investigated the effects of light digital touch on both postural sway and visual search accuracy for the purpose of assessing two hypotheses (functional integration and resource competition), which may explain the interaction between postural sway and the performance of a non-postural task. Participants (n=42, 20 male and 22 female) were asked to inspect a blank sheet of paper or visually search for target letters in a text block while a fingertip was in light contact with a stable surface (light touch, LT), or with both arms hanging at the sides of the body (no touch, NT). The results showed significant main effects of LT on reducing the magnitude of postural sway as well as enhancing visual search accuracy compared with the NT condition. The findings support the hypothesis of function integration, demonstrating that the modulation of postural sway can be modulated to improve the performance of a visual search task.