Motor imagery training ameliorates motor clumsiness in children

Children with impaired motor coordination (or developmental coordination disorder) have difficulty representing internally the visuospatial coordinates of intended movements. We have proposed that this deficit reflects impairment in the generation of forward models of the efference copy of intended movements-the efference-copy-deficit hypothesis. In this study, we challenged this hypothesis by examining the efficacy of an imagery intervention designed specifically to train the forward modeling of purposive actions. A pre-post design was adopted. Fifty-four children referred with motor coordination problems were assigned randomly to one of three groups: imagery training, traditional perceptual-motor training, and wait-list control. The imagery protocol-delivered by an interactive CD-ROM-was shown to be equally effective to perceptual-motor training in facilitating the development of motor skill in the referred children. These results support the efference-copy-deficit hypothesis in explaining the cause of motor clumsiness in most children. Directions for future intervention studies and remediation in the field of developmental clumsiness are discussed.     

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.     

Cognitive-motor interference during fine and gross motor tasks in children with Developmental Coordination Disorder (DCD)

BackgroundWhile typically developing children produce relatively automatized postural control processes, children with DCD seem to exhibit an automatization deficit. Dual tasks with various cognitive loads seem to be an effective way to assess the automatic deficit hypothesis.AimsThe aims of the study were: (1) to examine the effect of a concurrent cognitive task on fine and gross motor tasks in children with DCD, and (2) to determine whether the effect varied with different difficulty levels of the concurrent task.Methods and proceduresWe examined dual-task performance (Trail-Making-Test, Trail-Walking-Test) in 20 children with DCD and 39 typically developing children. Based on the idea of the Trail-Making-Test, participants walked along a fixed pathway, following a prescribed path, delineated by target markers of (1) increasing sequential numbers, and (2) increasing sequential numbers and letters. The motor and cognitive dual-task effects (DTE) were calculated for each task.ResultsRegardless of the cognitive task, children with DCD performed equally well in fine and gross motor tasks, and were slower in the dual task conditions than under single task-conditions, compared with children without DCD. Increased cognitive task complexity resulted in slow trail walking as well as slower trail tracing. The motor interference for the gross motor tasks was least for the simplest conditions and greatest for the complex conditions and was more pronounced in children with DCD. Cognitive interference was low irrespective of the motor task.Conclusions and implicationsChildren with DCD show a different approach to allocation of cognitive resources, and have difficulties making motor skills automatic. The latter notion is consistent with impaired cerebellar function and the “automatization deficit hypothesis”, suggesting that any deficit in the automatization process will appear if conscious monitoring of the motor skill is made more difficult by integrating another task requiring attentional resources.     

Health-related quality of life of children with Developmental Coordination Disorder

BackgroundAlthough Developmental Coordination Disorder (DCD) is primarily a motor disorder, it can also impact emotional and psychosocial functioning of children with this condition. Evidence suggests that children with DCD experience lower quality of life than their peers, but few studies have explicitly examined the health-related quality of life (HRQOL) of these children.AimsTo: (1) describe HRQOL of children with DCD compared to typically-developing children; (2) compare HRQOL from the perspectives of children with DCD and their parents; and (3) explore predictors of HRQOL for children with DCD.MethodsData from the KidScreen-52 and Strength and Difficulties Questionnaire were collected from 50 children with DCD [Mean(SD) age: 9.8 (1.2) years] and their parents and compared to normative data.ResultsChildren with DCD and their parents report significantly lower HRQOL compared to published norms. Caregivers have a significantly lower perception of their child’s HRQOL than their child’s self-report in many domains. Parents of children with DCD report that their children experience significantly more emotional and behavioral disturbances compared to norms. Poor motor function and attentional difficulties predict HRQOL.Conclusion and implicationsDCD appears to contribute to lower perceived HRQOL. Findings inform therapeutic targets for children with DCD, beyond motor skill intervention.     

Tool length influences reach distance estimation via motor imagery in children with developmental coordination disorder

Purpose: Children with developmental coordination disorder (DCD) often have difficulties with planning and generating a precise visuospatial representation of intended actions and using motor imagery to mentally represent motor behavior. Here, we aimed to extend the investigation of motor imagery in children with DCD by exploring its use with an estimation of reach paradigm that combines action representation and extension of space with tools. Method: Two groups of 18 children with DCD and typically developing (TD) matched controls were tested with an estimation of reach paradigm using a 20-cm (Experiment 1) and 40-cm (Experiment 2) tool. Conditions involved estimations via motor imagery with their arm, tool, and a switch-block (SB) involving an abrupt change of space with an “extension” from arm to tool and a “retraction” from tool to arm. Results: No significant group differences were found with the 20-cm tool; however, with the 40-cm implement, children with DCD were significantly less accurate than their TD counterparts. Conclusions: Compared to TD children, those with DCD have more difficulty estimating reach distances using the longer of two tool lengths: 40 cm compared to 20 cm. This finding may be related to differences in quality of motor imagery and in the ability to create an effective internal model for action in this context. Furthermore, our results suggest that tool length may present an additional action processing constraint on children with DCD. Additional studies are necessary to determine other constraints that children with DCD have when integrating tool use with spatial judgments for reach actions, as well as provide rehabilitation insights that involve motor imagery combined with tool use.     

Psychosocial adjustment and attention in children with developmental coordination disorder using different motor tests

This study examined the consistency between the findings of developmental coordination disorder (DCD) as identified by the Bruininks–Oseretsky Test of Motor Proficiency (BOTMP) and the Movement Assessment Battery for Children (MABC), and explored the psychosocial and attention characteristics of children with DCD identified by the two motor tests, respectively. Participants were 270 children (male: 161, female: 109; age 7.74 ± 0.81 years). The association between DCD status identified by each of the motor tests and psychosocial problems measured by the Child Behavioral Checklist-Chinese version (CBCL-C) was examined using multiple logistic regressions. The results showed that DCD identified by the BOTMP was associated with high scores on the Withdrawn and Social Problems, with a higher proportion of females identified. DCD identified by the MABC was associated with high scores on the Withdrawn and Attention Problems and low score on the Aggressive Behavior. The results reaffirmed the lack of consistency between the motor tests and indicated that children identified by the two motor tests showed different profiles of attention and psychosocial adjustment.     

Obesity and motor coordination ability in Taiwanese children with and without developmental coordination disorder

The purpose of this study was to investigate the associations between obesity and motor coordination ability in Taiwanese children with and without developmental coordination disorder (DCD). 2029 children (1078 boys, 951 girls) aged nine to ten years were chosen randomly from 14 elementary schools across Taiwan. We used bioelectrical impedance analysis to measure percentage of body fat (PBF) and the Movement Assessment Battery for Children test (MABC test) to evaluate the motor coordination ability. Using cut-off points based on PBF from past studies, boys and girls were divided into obese, overweight and normal-weight groups, respectively. In boys, total impairment scores and scores on balance subtest in the MABC were significantly higher in the obese and overweight groups when compared against the normal-weight group. Girls in the obese and the overweight groups had higher balance impairment scores than those of the normal-weight group. Among boys, the prevalence of obesity was highest in the DCD group, when compared to the borderline DCD and TD boys. A higher percentage of DCD girls were overweight and obese than TD girls. Obesity may be associated with poor motor coordination ability among boys and girls, and particularly in relation to balance ability. Children with DCD may have a higher risk to be overweight or obese in Taiwan.     

A systematic review of mirror neuron system function in developmental coordination disorder: Imitation,motor imagery,and neuroimaging evidence

PURPOSEThe aim of this systematic review was to investigate the evidence of abnormal functioning of the mirror neuron system (MNS) in children and adults with developmental coordination disorder (DCD), through examination of imitation, motor imagery, and neuroimaging literature.METHODSThe following databases were comprehensively searched for relevant articles: CINAHL Plus, Embase, MEDLINE, PsycINFO, Pubmed, and Web of Science. Full-text articles of all potentially relevant citations were obtained and assessed for eligibility by two authors. Outcome measures of interest at a motor behaviour level were any measures of imitation or motor imagery proficiency and, at a neurological level, were any measures of neural activity in MNS brain regions. Due to differences in outcome measures between studies and the variables reported, a narrative review was undertaken to synthesise findings from the studies.RESULTSOverall, 31 articles met the inclusion criteria. Children and adults with DCD display deficits imitating meaningful and novel gestures and demonstrate different response patterns to controls when undertaking complex motor imagery tasks. Children with DCD present reduced activation and connectivity of frontal, parietal, and temporal MNS regions.CONCLUSIONSPreliminary evidence indicates some deficit in the functioning of the MNS at a motor behaviour and neurological level. As no published neuroimaging studies have been designed specifically to explore MNS function, these results must be interpreted with caution. Further research to explore the MNS hypothesis in greater detail, particularly from a neuroimaging perspective, has the potential to provide information on the underlying mechanisms of DCD, inform future research into the aetiology of this disorder, and inform intervention approaches.     

Neuromotor task training for children with developmental coordination disorder: a controlled trial

The aim of this study was to evaluate neuromotor task training (NTT), a recently developed child-centred and task-oriented treatment programme for children with developmental coordination disorder (DCD). A treatment and a non-treatment control group of children with DCD were included. Children were selected if they scored below the 15th centile on the Movement Assessment Battery for Children (MABC). The children in the treatment group were recently referred for physiotherapy (n=26; 20 males, 6 females; mean age 7y 2mo [SD 1y 3mo]). The parents of the non-treated children were concerned about their children's motor performance and responded to advertisements for free testing (n=13; 10 males, 3 females; mean age 7y 2mo [SD 2y 1mo]). Before and after nine weekly 30-minute sessions of NTT or at least 9 weeks of no intervention, the MABC and the Test of Gross Motor Development - 2 (TGMD-2) were administered. Therapists reported per session on treatment goals and tasks trained. The results indicate that motor performance does not improve spontaneously and that NTT is effective. During the intervention period, only the treated group improved on the MABC and the TGMD-2. Children improved most on tasks similar to those trained. In older children with poorer motor patterns, NTT's treatment success was higher. The Child Behavior Checklist subscales withdrawn, thought problems, anxious/depressed, and delinquency were determinants of effects on motor patterns.     

Short-term motor learning of dynamic balance control in children with probable Developmental Coordination Disorder

PurposeTo explore the differences in learning a dynamic balance task between children with and without probable Developmental Coordination Disorder (p-DCD) from different cultural backgrounds.ParticipantsTwenty-eight Dutch children with DCD (p-DCD-NL), a similar group of 17 South African children (p-DCD-SA) and 21 Dutch typically developing children (TD-NL) participated in the study.MethodsAll children performed the Wii Fit protocol. The slope of the learning curve was used to estimate motor learning for each group. The protocol was repeated after six weeks. Level of motor skill was assessed with the Movement ABC-2.ResultsNo significant difference in motor learning rate was found between p-DCD-NL and p-DCD-SA, but the learning rate of children with p-DCD was slower than the learning rate of TD children. Speed–accuracy trade off, as a way to improve performance by slowing down in the beginning was only seen in the TD children, indicating that TD children and p-DCD children used different strategies. Retention of the level of learned control of the game after six weeks was found in all three groups after six weeks. The learning slope was associated with the level of balance skill for all children. This study provides evidence that children with p-DCD have limitations in motor learning on a complex balance task. In addition, the data do not support the contention that learning in DCD differs depending on cultural background.     

Examining the relationship between motor assessments and handwriting consistency in children with and without probable Developmental Coordination Disorder

Children with Developmental Coordination Disorder (DCD) often experience difficulties in handwriting. The current study examined the relationships between three motor assessments and the spatial and temporal consistency of handwriting. Twelve children with probable DCD and 29 children from 7 to 12 years who were typically developing wrote the lowercase letters “e” and “l” in cursive and printed forms repetitively on a digitizing tablet. Three behavioral assessments, including the Beery–Buktenica Developmental Test of Visual-Motor Integration (VMI), the Minnesota Handwriting Assessment (MHA) and the Movement Assessment Battery for Children (MABC), were administered. Children with probable DCD had low scores on the VMI, MABC and MHA and showed high temporal, not spatial, variability in the letter-writing task. Their MABC scores related to temporal consistency in all handwriting conditions, and the Legibility scores in their MHA correlated with temporal consistency in cursive “e” and printed “l”. It appears that children with probable DCD have prominent difficulties on the temporal aspect of handwriting. While the MHA is a good product-oriented assessment for measuring handwriting deficits, the MABC shows promise as a good assessment for capturing the temporal process of handwriting in children with DCD.     

Participation patterns of school-aged children with and without DCD

Participation is recognized as a key to one's health and well-being and is considered to be a vital part of the development of children and youth. The purpose of this study was to examine the participation patterns of children with and without Developmental Coordination Disorder (DCD) in their out-of-school-time (OST) activities, and to see whether there is a relationship between the children's motor abilities and their choices and participation. Methods: 50 children (5-7 years old), 25 who met diagnostic criteria of DCD and 25 without DCD, completed the Children Assessment of Participation and Enjoyment (CAPE) and were administered the Motor Assessment Battery for Children (MABC) and the Beery-Buktenica Developmental Test of Visual-Motor Integration (VMI). Results: A relationship was found between participation patterns and motor ability. Children with DCD had limited participation diversity in which they participated less frequently, and chose activities that were quieter and more socially isolated compared to children without DCD; there were no differences in their levels of enjoyment. Conclusions: The present study emphasizes the importance of looking at the children's participation from a broad perspective, and the many difficulties children with DCD experience in OST participation. Future studies might consider other factors (e.g., environment) while examining participation among children with DCD.     

Mild impairments of motor imagery skills in children with DCD

It has been hypothesized that the underlying mechanism of clumsy motor behaviour in children with Developmental Coordination Disorder (DCD) is caused by a deficit in the internal modelling for motor control. An internal modelling deficit can be shown on a behavioural level by a task that requires motor imagery. Motor imagery skills are suggested to be related to anticipatory action planning, but motor imagery and action planning have not been tested within the same child. In the present study, action planning and motor imagery skills were assessed in 82 children between 7 and 12 years of age. Twenty-one of these children met the criteria for DCD, which was assessed by the McCarron Assessment of Neuromuscular Development and 56 of these children were used in the control group. Motor imagery was tested by a mental rotation task of hands that were shown from a back and palm point of view. The results show that motor imagery is affected in children with DCD but only in conditions with complex task constraints (i.e., rotation of hand stimuli presented in palm view). These results provide partial support for the internal modelling deficit hypothesis. We were not able to elicit motor planning deficits in this group, however, and argue that more complex planning tasks may be needed to identify such deficits.     

Association between visual perceptual deficits and motor deficits in children with developmental coordination disorder

This study explored the relation between a motor-free visual perceptual deficit, different visual-motor integration deficits, and different motor skills in children with developmental coordination disorder (DCD). Thirty-six children (22 males), aged 9 or 10 years, with DCD and a control group (n=36), matched for age and sex, were assessed with the Movement Assessment Battery for Children (MABC), a ball-catching test, a jumping test, a timed response task to a visual moving stimulus, and the Beery-Buktenica Developmental Test of Visual-Motor Integration, incorporating copying, visual discrimination, and tracing tasks. Children with DCD performed significantly worse than the control group on all measures. The visual discrimination task did not correlate significantly with any of the motor tasks. The visual timing task correlated significantly with the ball-catching test in the DCD group. The copying test was significantly correlated with the MABC in the DCD group. The association between visual-perceptual deficits and motor tasks was shown to be task specific.     

Reliability and responsiveness of the Movement Assessment Battery for Children-Second Edition Test in children with developmental coordination disorder

Aim To examine the internal consistency, test–retest reliability, and responsiveness of the Movement Assessment Battery for Children–Second Edition (MABC‐2) Test for children with developmental coordination disorder (DCD). Method One hundred and forty‐four Taiwanese children with DCD aged 6 to 12 years (87 males, 57 females) were tested on three separate occasions: two baseline measurements with a 20‐day interval before the intervention, and a follow‐up measurement after 6 months of rehabilitation. The therapists rated the performance of children in school‐related physical tasks at baseline and after intervention. Results Internal consistency for the MABC‐2 Test was α = 0.90. Test–retest reliability for the total score was excellent, with an intraclass correlation coefficient of 0.97. A small to medium magnitude of treatment effect was captured by the MABC‐2 Test. The minimal detectable change (MDC) was 0.28 points whereas the minimal important difference (MID) values were from 2.36 to 2.50. All subscales except balance showed acceptable validity in differentiating groups of children whose physical performance had improved or remained stable. Interpretation The MABC‐2 Test is a reliable and valid measure to assess motor competence in children with DCD. The MID and MDC scores provide the reference point for clinical decision‐making in managing the individual child.     

Motor ability and weight status are determinants of out-of-school activity participation for children with developmental coordination disorder

According to the International Classification of Functioning, Disability and Health model endorsed by the World Health Organization, participation in everyday activities is integral to normal child development. However, little is known about the influence of motor ability and weight status on physical activity participation in children with developmental coordination disorder (DCD). This study aimed to (1) compare motor performance, weight status and pattern of out-of-school activity participation between children with DCD and those without; and (2) identify whether motor ability and weight status were determinants of participation patterns among children with DCD. We enrolled 81 children with DCD (boys, n = 63; girls, n = 18; mean age, 8.07 ± 1.5 years) and 67 typically developing children (boys, n = 48; girls, n = 19; mean age, 8.25 ± 1.6 years). Participation patterns (diversity, intensity, companionship, location, and enjoyment) were evaluated with the Children Assessment of Participation and Enjoyment. Motor ability was evaluated with the Movement Assessment Battery for Children, second edition (MABC-2). Other factors that may influence participation such as age, gender, and body weight were also recorded. Analysis of variance was used to compare outcome variables of the two groups, and significant determinants of activity participation were identified by multiple regression analysis. Children with DCD participated in fewer activities (i.e., limited participation diversity) and participated less frequently (i.e., limited participation intensity) than their typically developing peers; however, companionship, location of participation, and enjoyment level did not differ between the two groups. Children in the DCD group demonstrated significantly worse motor ability as assessed by the MABC-2. Further, a greater proportion of children in the DCD group were in the overweight/obese category compared with their typically developing peers. After accounting for the effects of age and gender, motor ability and weight category explained 7.6% and 5.0% of the variance in participation diversity, respectively, for children with DCD. Children with DCD showed less diverse and less intense out-of-school activity participation than typically developing children. Motor impairment and weight status were independently associated with the lower participation diversity. Interventions aiming at improving participation for children with DCD should target weight control and training in motor proficiency. Further study is needed to identify other factors that may hinder participation in this group of children.     

The effectiveness of exercise intervention on inhibitory control in children with developmental coordination disorder: Using a visuospatial attention paradigm as a model

Children with developmental coordination disorder (DCD) have been demonstrated to show a deficit of inhibitory control in volitional shifts of attention. The aim of this study was to use ecological intervention to investigate the efficacy of table-tennis training on treating both problems with attentional networks and motor disorder in children with DCD. Forty-three children aged 9–10 years old were screened using the Movement Assessment Battery for Children and divided into DCD (n = 27) and typically developing (TD, n = 16) groups. Children with DCD were then quasi-randomly assigned to either a DCD-training group who underwent a ten-week table-tennis training program with a frequency of 3 times a week or a DCD non-training group. Before and after training, the capacity of inhibitory control was examined with the endogenous Posner paradigm task for DCD and TD groups. Table-tennis training resulted in significant improvement of cognitive and motor functions for the children with DCD. The study demonstrated that exercise intervention employed within the school setting can benefit the inhibitory control and motor performance in children with DCD. However, future research efforts should continue to clarify whether the performance gains could be maintained over time.     

Toward a motor signature in autism: Studies from human-machine interaction

BackgroundAutism spectrum disorder (ASD) is a heterogeneous group of neurodevelopmental disorders which core symptoms are impairments in socio-communication and repetitive symptoms and stereotypies. Although not cardinal symptoms per se, motor impairments are fundamental aspects of ASD. These impairments are associated with postural and motor control disabilities that we investigated using computational modeling and developmental robotics through human-machine interaction paradigms.MethodFirst, in a set of studies involving a human–robot posture imitation, we explored the impact of 3 different groups of partners (including a group of children with ASD) on robot learning by imitation. Second, using an ecological task, i.e. a real-time motor imitation with a tightrope walker (TW) avatar, we investigated interpersonal synchronization, motor coordination and motor control during the task in children with ASD (n = 29), TD children (n = 39) and children with developmental coordination disorder (n = 17, DCD).ResultsFrom the human–robot experiments, we evidenced that motor signature at both groups’ and individuals’ levels had a key influence on imitation learning, posture recognition and identity recognition. From the more dynamic motor imitation paradigm with a TW avatar, we found that interpersonal synchronization, motor coordination and motor control were more impaired in children with ASD compared to both TD children and children with DCD. Taken together these results confirm the motor peculiarities of children with ASD despite imitation tasks were adequately performed.DiscussionStudies from human-machine interaction support the idea of a behavioral signature in children with ASD. However, several issues need to be addressed. Is this behavioral signature motoric in essence? Is it possible to ascertain that these peculiarities occur during all motor tasks (e.g. posture, voluntary movement)? Could this motor signature be considered as specific to autism, notably in comparison to DCD that also display poor motor coordination skills? We suggest that more work comparing the two conditions should be implemented, including analysis of kinematics and movement smoothness with sufficient measurement quality to allow spectral analysis.     

Coupling online control and inhibitory systems in children with Developmental Coordination Disorder: Goal-directed reaching

For children with Developmental Coordination Disorder (DCD), the real-time coupling between frontal executive function and online motor control has not been explored despite reported deficits in each domain. The aim of the present study was to investigate how children with DCD enlist online control under task constraints that compel the need for inhibitory control. A total of 129 school children were sampled from mainstream primary schools. Forty-two children who met research criteria for DCD were compared with 87 typically developing controls on a modified double-jump reaching task. Children within each skill group were divided into three age bands: younger (6–7 years), mid-aged (8–9), and older (10–12). Online control was compared between groups as a function of trial type (non-jump, jump, anti-jump). Overall, results showed that while movement times were similar between skill groups under simple task constraints (non-jump), on perturbation (or jump) trials the DCD group were significantly slower than controls and corrected trajectories later. Critically, the DCD group was further disadvantaged by anti-jump trials where inhibitory control was required; however, this effect reduced with age. While coupling online control and executive systems is not well developed in younger and mid-aged children, there is evidence of age-appropriate coupling in older children. Longitudinal data are needed to clarify this intriguing finding. The theoretical and applied implications of these results are discussed.     

Developmental coordination disorder at 8 years of age in a regional cohort of extremely-low-birthweight or very preterm infants

The aims of this study were to determine the motor outcome of extremely-low-birthweight (ELBW; <1000g) or very preterm (<28wks) children compared with normal birthweight (NBW) children, to establish the perinatal associations of developmental coordination disorder (DCD) and its cognitive and behavioural consequences. Participants were consecutive surviving ELBW or very preterm children and randomly selected NBW(>2499g) children born in the state of Victoria, Australia, in 1991 or 1992. Main outcomes were: (1) results of the Movement Assessment Battery for Children (MABC) at 8 years of age; (2) cognitive function; (3) academic progress; and (4) behaviour. Of 298 consecutive ELBW/very preterm survivors, 255 (85.6%; 117 males, 138 females) had the MABC at a mean age of 8 years 8 months. More ELBW/very preterm children (9.5%) had DCD than the NBW group (2%, p=0.001). Only male sex increased the likelihood of DCD in ELBW/very preterm children (p=0.017). ELBW/very preterm children with DCD had worse cognitive function and academic test scores (up to 1SD below those without DCD); they also had more adaptive behaviour and externalizing problems, but not internalizing problems. DCD is more common in ELBW/very preterm children, has few perinatal correlates, and is associated with poor cognitive and academic performance as well as increased behaviour problems.