Motor and cognitive dual-task performance under low and high task complexity in children with and without developmental coordination disorder.

BACKGROUND: In everyday life, tasks are often performed simultaneously, which may be more difficult for children with developmental coordination disorder (DCD) than their peers. AIMS: To examine (1) the effects of task complexity and type of concurrent task on dual-task performance in children with and without DCD; and (2) if the amount of effort that children put into the task performance differs between the groups. METHODS: Participants were 64 children with and without DCD (aged 7-14 years). The dual-task paradigm consisted of a manual dexterity task of relatively low complexity (box and block test) or relatively high complexity (pegboard task), and a concurrent motor task (cycling task) or a concurrent cognitive task (word-listening task). To assess mental effort, children were asked how tired they felt before and after the experiment. RESULTS: Dual-task interference was highest when the manual dexterity task of relatively high complexity was combined with the concurrent motor task. There were no group differences in dual-task interference, but children with DCD reported a larger increase in the level of tiredness after the experiment indicative of greater mental effort. CONCLUSIONS: Depending on task demands, children with DCD are able to perform dual-tasks at the same level as their peers, but performance may take children with DCD more mental effort.

End-state comfort planning after explicit goal instructions in children with and without probable developmental coordination disorder.

BACKGROUND: When completing grip-selection tasks, healthy adults generally plan for the most comfortable end-posture which is termed the end-state comfort (ESC) effect. Children with and without developmental coordination disorder (DCD) are less likely to plan for ESC which begs the question as to whether they are not able to perform this type of planning or whether they prioritize other aspects of the task. AIMS: (1) Examine if children with and without probable DCD (pDCD) are able to plan for ESC if they are explicitly instructed to and (2) if this transfers to another similar task. (3) Examine if children with and without pDCD perceive the level of comfort of the grips that they use differently and if this relates to ESC planning. METHODS: Twelve children with and 12 children without probable DCD (pDCD) (aged 5-9 years) received a 10-min training session in which children were explicitly instructed to end their movement in ESC, after which they formulated their own plan to reach this goal. The study consisted of a pre-post-test design in which changes in the proportion of ESC were analyzed on the task that was trained as well as on an untrained transfer-task. Furthermore, the perceived level of comfort was examined. RESULTS: Both groups of children showed a higher proportion of ESC on the post-test compared with the pre-test, on the task that was trained as well as on the transfer-task. There were no group differences regarding the perceived level of comfort of the different grip postures. CONCLUSION: The majority of the children with and without pDCD seems to be able to adjust their planning strategy and prioritize ESC if they are explicitly instructed to.

Benefits of an Intensive Individual CO-OP Intervention in a Group Setting for Children with DCD.

Purpose: The present study focused on the impact of an adapted Cognitive Orientation to daily Occupational Performance (CO-OP) five-day intervention program for children with developmental coordination disorder (DCD). Important adaptations were the new combination of individual CO-OP sessions and group activities, the short and intensive program that was followed by a training and coaching trajectory, and the use of video logs. Materials and Methods: Eighteen children with DCD (aged 8-16 years) participated in the five-day intervention during which they worked on three intervention goals. After the intervention, during an eight-week training and coaching trajectory for parents and children, children worked on a transfer goal. Assessment took place at four moments in time: two pretest measures, a posttest measure, and a 3-month follow-up measure. Primary outcome measures focused on changes in performance and satisfaction of self-chosen intervention and transfer goals. The secondary outcome measure explored changes in children's attitude, motivation, and confidence in relation to motor skill activities, social skills, and level of participation. Results: Significant improvements were found with regard to the performance and satisfaction of intervention goals. For the transfer goal, only parents reported significant improvements. Finally, parents indicated potential improvements with regard to the attitude, motivation, and confidence of their children, but not for their social skills or level of participation. Conclusion: The findings are promising with regard to the efficacy of this adapted CO-OP intervention for improving intervention goals, but less effective for transfer of learned skills to other goals after the intervention. Future research should focus on how postintervention parental coaching can be improved in order to increase generalization and transfer.

Second-order motor planning difficulties in children with developmental coordination disorder.

The second-order motor planning ability of children with developmental coordination disorder (DCD) has often been studied using tasks that require judgements of end-state comfort (ESC). In these studies, children may have chosen to prioritize other aspects of performance (e.g., a comfortable start-posture) over ESC while still being able to complete the goal of the task. This is a limitation that is inherent to previously used ESC paradigms. To avoid this in the present study, 52 children with and without DCD (aged 5-12 years) completed a task that requires second-order motor planning for its successful completion. In the hexagonal knob task, children were instructed to grasp and rotate a hexagonal knob. The rotation angle varied in size: 60°, 120°, 180°, and 240° rotations. Both the 180° and 240° rotation conditions required an uncomfortable starting posture for successful task completion. Results showed that children with DCD were less likely to adjust their initial grip in anticipation of the required rotation angle, resulting in more task failures compared with typically developing (TD) children. Based on this finding we conclude that children with DCD experience genuine second-order motor planning difficulties. Analysis of temporal outcomes, showed that initial reaction time increased with rotation angle, but this was less pronounced for children with DCD than for TD children. There were no between group differences in timing of subsequent events. These results suggest that the difficulties of children with DCD are related to the initial planning process, that is, before the start of the movement.

Eliciting End-State Comfort Planning in Children With and Without Developmental Coordination Disorder Using a Hammer Task: A Pilot Study.

The end-state comfort (ESC) effect refers to the consistent tendency of healthy adults to end their movements in a comfortable end posture. In children with and without developmental coordination disorder (DCD), the results of studies focusing on ESC planning have been inconclusive, which is likely to be due to differences in task constraints. The present pilot study focused on the question whether children with and without DCD were able to change their planning strategy and were more likely to plan for ESC when demanded by complex object manipulations at the end of a task. To this end, we examined ESC planning in 18 children with and without DCD (aged 5-11years) using the previously used sword-task and the newly developed hammer-task. In the sword-task, children had to insert a sword in a wooden block, which could be relatively easily completed with an uncomfortable end-posture. In the hammer-task, children had to strike down a nail in a wooden pounding bench, which required additional force and speed demands, making it relatively difficult to complete the movement with an uncomfortable end-posture. In line with our hypothesis, the results demonstrated that children with and without DCD were more likely to plan for ESC on the hammer-task compared with the sword-task. Thus, while children with and without DCD show inconsistent ESC planning on many previously used tasks, the present pilot study shows that many of them are able to take into account the end-state of their movements if demanded by task constraints.

Motor imagery and action observation for predictive control in developmental coordination disorder.

In 2019, international clinical practice recommendations on the definition, diagnosis, assessment, intervention, and psychosocial aspects of developmental coordination disorder (DCD) were published. Informing our understanding of mechanisms, recent systematic reviews have shown that children with DCD have difficulties with the predictive control of movements, including aspects of motor planning, which is expressed as the internal modeling deficit hypothesis. This motor control deficit is most evident when the spatial and temporal demands of a task increase. An increasing number of empirical studies suggest that motor planning problems can be remediated through training based on one or a combination of motor imagery and action observation. In this review, we show evidence of motor planning problems in children with DCD and show that task demands or complexity affects its appearance. Implications of these findings are treatments based on motor imagery and action observation to remediate motor planning issues. The article concludes with recommendations for future research.

Development of motor planning in children: Disentangling elements of the planning process.

Second-order motor planning of grasping movements is usually measured using tasks that focus on the relative (dis)comfort of end posture of the arm and hand regardless of the objective outcome of performance. This may underestimate the ability for forward planning in young children. In the current study, we aimed to examine the developmental mechanisms of motor planning in children using a task that necessitates second-order motor planning for its successful completion. We tested 311 children (aged 5-12 years) who were instructed to grasp and rotate a hexagonal knob over 60°, 120°, 180°, or 240°. The 180° and 240° rotation conditions necessitated adjustment of the preferred start grip for successful task completion. We examined successful or unsuccessful task completion, reaction time (RT), and movement time (MT) as a function of task demands (i.e., rotation angle) and age. Results showed that most children of all ages were able to successfully complete the task in the 180° rotation condition. In the most demanding 240° rotation condition, many children had difficulty in completing the task, but successful task completion increased with age. Time course analysis showed increased RT and MT with increasing task demands. Furthermore, whereas RT decreased with age for each rotation angle, MT remained stable with the exception of an increase in MT for the most demanding rotation condition. Together, these results exemplify that children aged 5-12 years are indeed able to engage in forward planning. With development, second-order motor planning proficiency increases, especially for more demanding movements, and the process becomes more efficient.

The development of anticipatory action planning in children with unilateral cerebral palsy.

Background Previous studies suggest that compromised bimanual performance experienced by children with unilateral cerebral palsy (CP) is not only due to difficulties in action execution but may also be a result of impaired anticipatory action planning. Aims The effect of age and side of hemiplegia were examined and the relationship between anticipatory action planning, unimanual capacity and bimanual performance was explored. Methods and procedures Using a multi-centre, prospective, cross-sectional observational design, anticipatory action planning was analyzed in 104 children with unilateral cerebral palsy, aged 6-12 years, using the sword task. Outcomes and results Anticipatory action planning did not improve with age in children with unilateral CP, aged between 6-12 years. No differences were found between children with left or right hemiplegia. Finally, anticipatory action planning was not related to unimanual capacity or bimanual performance. Conclusion and implications This study demonstrates anticipatory action planning, measured using the sword task, does not improve with age in children with unilateral CP and is not related to bimanual performance or laterality. Future studies of anticipatory action planning in children with unilateral CP should consider using measures that require effective anticipatory action planning for successful task completion rather than end state comfort.

Motor learning in children with developmental coordination disorder: The role of focus of attention and working memory.

Effective motor learning paradigms are essential for children with motor difficulties to enhance their motor skills and facilitate performance in physical activities and in daily life. This study aimed to examine the effect of feedback with an internal or external focus of attention on motor learning of children with probable Developmental Coordination Disorder (pDCD). In addition, the role of working memory capacity was examined. Children were recruited via physical therapists, who integrated the experimental procedures within therapy sessions. We analyzed data of 25 children between 5 and 11 years old. They practiced a novel motor task of throwing a 'slingerball' over three weeks, while receiving feedback with an internal or external focus of attention. Results showed that children improved throwing accuracy regardless of the type of feedback they received. Visuospatial working memory capacity enhanced learning, especially for children receiving feedback with an external focus of attention. These findings corroborate clinical recommendations stating that children with DCD benefit from task specific training and feedback, which is promoted with both foci of attention. However, the findings contrast the expected benefits of practice with an external focus of attention. It highlights that the exact mechanisms and task constraints that influence the learning processes with an internal and external focus among children are not yet understood and warrant further study.

Motor learning and movement automatization in typically developing children: The role of instructions with an external or internal focus of attention.

The aim of the current study was to examine the effects of an external focus of attention (i.e., on the movement outcome) versus an internal focus of attention (i.e., on the movement itself) on motor learning in typically developing children. We examined both immediate motor performance (i.e., practice effect, when focus instructions are given) as well as motor performance after one week (i.e., learning effect). In addition, we examined if an external and an internal focus of attention differently affected movement automatization, as measured using a dual-task paradigm. Finally, we explored whether the effect of attentional focus instructions on motor learning was influenced by children's working memory capacity. Participants were 8-12 year old (N = 162) typically developing children. Participants practiced a new motor task (i.e., 'Slingerball throwing task'). Results showed that an external focus of attention led to higher throwing accuracy during practice, but this beneficial effect did not extent to the retention test one week later. Furthermore, movement automatization did not differ after external or internal focus of attention instructions, and working memory capacity did not predict motor learning in children in either of the instruction conditions. This is the first study to show that the beneficial effects of an external focus of attention on discrete motor tasks found in previous studies with a child population seem to be short lived and decline after a one-week interval.