Jessica M. Lust

Compromised motor control in children with DCD: A deficit in the internal model - a systematic review

A viable hypothesis to explain the compromised motor ability of children with Developmental Coordination Disorder (DCD) suggests a fundamental deficit in their ability to utilize internal models for motor control. Dysfunction in this mode of control is thought to compromise their motor learning capabilities. The aim of this systematic review is to examine the available evidence for the internal modeling deficit (IMD) hypothesis. A systematic review using five databases identified 48 relevant articles. These studies were categorized according to the effector system involved in the evaluation of motor control and were evaluated for methodological quality. In most papers, DSM-IV-TR criteria for the classification of DCD were not completely fulfilled and possible attentional problems not accounted for. Results showed compromised control of overt and covert eye movements, dynamic postural control, manual control for tasks that vary in complexity, and for motor imagery of manual and whole-body postures. Importantly, this review shows support for general hypothesis that deficits of predictive control manifest in DCD across effector systems.

Action planning and position sense in children with Developmental Coordination Disorder

The present study examined action planning and position sense in children with Developmental Coordination Disorder (DCD). Participants performed two action planning tasks, the sword task and the bar grasping task, and an active elbow matching task to examine position sense. Thirty children were included in the DCD group (aged 6-10years) and age-matched to 90 controls. The DCD group had a MABC-2 total score ⩽5th percentile, the control group a total score ⩾25th percentile. Results from the sword-task showed that children with DCD planned less for end-state comfort. On the bar grasping task no significant differences in planning for end-state comfort between the DCD and control group were found. There was also no significant difference in the position sense error between the groups. The present study shows that children with DCD plan less for end-state comfort, but that this result is task-dependent and becomes apparent when more precision is needed at the end of the task. In that respect, the sword-task appeared to be a more sensitive task to assess action planning abilities, than the bar grasping task. The action planning deficit in children with DCD cannot be explained by an impaired position sense during active movements.

Development of motor imagery and anticipatory action planning in children with developmental coordination disorder: A longitudinal approach

Children with impaired motor coordination (or Development Coordination Disorder - DCD) have difficulty with the predictive control of movements, evidenced by cross-sectional studies that show impaired motor imagery and action planning abilities. What remains unclear is whether this deficit in predictive control reflects immaturity of the motor system (a developmental delay) or some deviation from normal development (a disorder). To advance this discussion the present study used a longitudinal design to examine the development of motor imagery and action planning in children with DCD. Thirty children were included in the DCD group (aged 6-11years) and age- and gender-matched to 30 controls. The DCD group had a mABC-2 score≤16th percentile, the control group>20th percentile. Motor imagery was assessed with the hand rotation task, action planning with a test for end-state comfort. Children participated in three measurements, with one year in between measurements. Results showed that children with DCD were slower and less accurate than their typically developing peers in all subsequent years but were able to improve their motor imagery ability over time. Furthermore, children with DCD showed less planning for ESC at the start of the present study, but were able to catch up with their peers during two-year follow up. These results exemplify that improvement of motor imagery and action planning ability is possible in DCD, and they lend theoretical support to the use of new training techniques that focus on training motor imagery to improve motor skills in children with DCD.

Feasibility of motor imagery training for children with Developmental Coordination Disorder: A pilot study

Children with Developmental Coordination Disorder (DCD) experience movement difficulties that may be linked to processes involved in motor imagery (MI). This paper discusses recent advances in theory that underpin the use of MI training for children with DCD. This knowledge is translated in a new MI training protocol which is compared with the cognitive orientation to daily occupational performance (CO-OP). Children meeting DSM-5 criteria for DCD were assigned to MI (n = 4) or CO-OP (n = 4) interventions and completed nine treatment sessions, including homework exercises. Results were positive, with two children in the MI group and three in the CO-OP group improving their m-ABC-2 score by ≥ 2 standard scores, interpreted as a clinically meaningful change. Moreover, all children and parents noticed improvements in motor skills after training. This is the first study to demonstrate the feasibility of a theoretically principled treatment protocol for MI training in children with DCD, and extends earlier work. Trial registration: The complete trial is registered at the Dutch trial register, www.trialregister.nl (NTR5471). http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=5471

Motor imagery difficulties in children with Cerebral Palsy: A specific or general deficit?

AIM The aim of this study was to examine the specificity of motor imagery (MI) difficulties in children with CP. METHOD Performance of 22 children with CP was compared to a gender and age matched control group. MI ability was measured with the Hand Laterality Judgment (HLJ) task, examining specifically the direction of rotation (DOR) effect, and the Praxis Imagery Questionnaire (PIQ). RESULTS In the back view condition of the HLJ task both groups used MI, as evidenced by longer response times for lateral compared with medial rotational angles. In the palm view condition children with CP did not show an effect of DOR, unlike controls. Error scores did not differ between groups. Both groups performed well on the PIQ, with no significant difference between them in response pattern. CONCLUSION AND IMPLICATION The present study suggests that children with CP show deficits on tasks that trigger implicit use of MI, whereas explicit MI ability was relatively preserved, as assessed using the PIQ. These results suggest that employing more explicit methods of MI training may well be more suitable for children with CP in rehabilitation of motor function.

Is cerebrale lateralisatie voordelig voor de prestatie bij dubbeltaken? Een fTCD-studie naar de functie van cerebrale lateralisatie

Het brein bestaat uit twee hemisferen, waartussen het corpus callosum de voornaamste verbinding vormt. De mate waarin ieder van de hemisferen betrokken is bij een taak is afhankelijk van de aard van die taak. Zo is de linker hemisfeer bij veel mensen meer betrokken bij talige taken (zoals het bedenken van woorden die beginnen met een bepaalde letter) dan de rechter hemisfeer. Aan de andere kant is de rechter hemisfeer vaak juist sterker betrokken bij het uitvoeren van visuospatiële taken (zoals het vinden van de weg). Dit verschil in betrokkenheid van de hemisferen bij verschillende taken wordt cerebrale lateralisatie genoemd.Vroeger dacht men dat cerebrale lateralisatie specifiek was voor de mens. Tegenwoordig is bekend dat lateralisatie voorkomt bij alle gewervelde soorten en ook bij enkele ongewervelde soorten. Dit maakt het zeer waarschijnlijk dat lateralisatie van functies in het brein vroeg in de evolutie is ontstaan. Dat lateralisatie de evolutie heeft doorstaan doet vermoeden dat het voordelig is voor de overleving. Het is echter nog altijd niet precies bekend hoe het komt dat we een gelateraliseerd brein hebben en wat de voordelen zouden kunnen zijn.AbstractIt has been hypothesized that functional cerebral lateralization enhances cognitive performance. Evidence was found in birds and fish. Our study aimed to test this hypothesis by analyzing the relationship between cerebral lateralization and both single-task performance and dualtask efficiency in two studies in humans. In the first study we combined a dynamic Landmark task which is assumed to be primarily processed in the right hemisphere and a frequently used word generation task which is assumed to be primarily processed in the left hemisphere. In the second study we replaced the dynamic Landmark task with a simulator based driving task which is also assumed to be primarily processed in the right hemisphere. For each task individual strength and direction of hemispheric lateralization was assessed using functional transcranial Doppler sonography (fTCD). For each subject (26 in study 1; 71 in study 2), performance was measured in the two single-tasks and in the dual-task condition.On average, subjects showed a left hemisphere bias for the word generation task and a right hemisphere bias for both the driving task and the dynamic Landmark task.The results show no indication of a positive effect of strength of lateralization on performance in single-task or dual-task efficiency. Also, we found no consistent advantage of a typical compared to an atypical or a contralateral compared to an ipsilateral lateralization pattern. Moreover, the results showed a slight negative, rather than a positive trend between strength of lateralization and dual-task efficiency. The results therefore do not support the parallel processing hypothesis of cerebral lateralization and suggest that lateralization does not enhance cognitive performance in humans.

Motor planning in children with cerebral palsy: A longitudinal perspective

ABSTRACT Introduction: Motor planning is important for daily functioning. Deficits in motor planning can result in slow, inefficient, and clumsy motor behavior and are linked to disruptions in performance of activities of daily living in children with cerebral palsy (CP). However, the evidence in CP is primarily based on cross-sectional data. Method: Data are presented on the development of motor planning in children with CP using a longitudinal design with three measurement occasions, each separated by 1 year. Twenty-two children with CP (9 boys, 13 girls; age in years;months, M = 7;1, SD = 1;2) and 22 age-matched controls (10 boys, 12 girls, M = 7;1, SD = 1;3) participated. Children performed a bar transport task in which some conditions (“critical angles”) required participants to sacrifice initial posture comfort in order to achieve end-state comfort. Performance on critical trials was analyzed using linear growth curve modeling. Results: In general, children with CP showed poor end-state planning for critical angles. Importantly, unlike in controls, motor planning ability did not improve across the three measurement occasions in children with CP. Conclusion: These longitudinal results show that motor planning issues in CP do not resolve with development over childhood. Strategies to enhance motor planning are suggested for intervention.