Metabolic syndrome in children with and without developmental coordination disorder

Children with developmental coordination disorder (DCD) have higher rates of obesity compared to children with typical motor development, and, as a result may be at increased risk for developing metabolic syndrome (MetS). The purpose of this study was to determine the presence of MetS and its components among children with and without DCD. This nested case-control study classified 63 children scoring below the 16th percentile on the Movement Assessment Battery for Children (M-ABC-2) as probable DCD (pDCD), and 63 controls, all of whom scored above the 16th percentile. Metabolic syndrome was defined using the International Diabetes Federation (IDF) criteria. Eleven children met the criteria for MetS; 8 (72.3%) with pDCD and 3 (27.3%) controls (p = 0.115). Abdominal obesity was found in 39 (30.9%) of children, 29 (46.0%) with pDCD and 10 (15.9%) controls (p < 0.01). Serum triglycerides were higher in pDCD compared to controls, 91.9 mg/dl (63.1) vs. 67.7 mg/dl (33.3) in the control group, p = 0.001. Blood pressure was also significantly higher in the pDCD group, mean systolic BP (110 vs. 105 mmHg, p = 0.01) and mean diastolic BP (69 vs. 65 mmHg, p = 0.01). There were no statistically significant differences between the groups for other components of MetS. The higher prevalence of abdominal obesity and elevated triglycerides and blood pressure in children with pDCD may put them at risk of meeting all criteria of MetS earlier then their peers.     

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.     

Similarities and dissimilarities between the Movement ABC-2 and the Zurich Neuromotor Assessment in children with suspected developmental coordination disorder

An established tool for the assessment of motor performance in children with developmental coordination disorder (DCD) is the Movement-ABC-2 (M-ABC-2). The Zurich Neuromotor Assessment (ZNA) is also widely used for the evaluation of children's motor performance, but has not been compared with the M-ABC-2. Fifty-one children (39 males) between 5 and 7 years of age with suspected DCD were assessed using the M-ABC-2 and the ZNA. Rank correlations between scores of different test components were calculated. The structure of the tests was explored using canonical-correlation analysis. The correlation between total scores of the two motor tests was reasonable (0.66; p < 0.001). However, ZNA scores were generally lower than those of M-ABC-2, due to poor performance in the fine motor adaptive component and increased contralateral associated movements (CAM). The canonical-correlation analysis revealed that ZNA measures components like pure motor skills and CAM that are not represented in the M-ABC-2. Furthermore, there was also no equivalent for the aiming and catching items of the M-ABC-2 in ZNA. The two tests measure different motor characteristics in children with suspected DCD and, thus, can be used complementary for the diagnosis of the disorder.     

High risk for obesity in children with a subtype of developmental coordination disorder

The purpose of this study was to compare the prevalence of overweight and obesity in typically developing (TD) children, children with developmental coordination disorder (DCD) and balance problems (DCD-BP), and children with DCD without balance problems (DCD-NBP). Two thousand and fifty-seven children (1095 boys, 962 girls) ages 9–12 years were recruited from 18 elementary schools in Taiwan. The Movement Assessment Battery for Children was used to assess motor coordination ability. International cut-off points for body mass index were used to classify participants into the following groups: normal-weight, overweight or obese. Compared with TD children, children in the DCD-BP group were more than twice as likely to be obese (OR = 2.28; 95% CI = 1.41–3.68). DCD-BP children were also more likely to be obese compared to DCD-NBP children (OR = 1.79; 95% CI = 1.02–3.16). Boys in the DCD-BP group were more likely to be obese when compared to DCD-BP girls (OR = 3.12; 95% CI = 1.28–7.57). Similarly, DCD-NBP boys were more likely to be obese when compared to DCD-NBP girls (OR = 2.67; 95% CI = 1.21–5.89). Children with both DCD and BP were significantly more likely to be obese when compared to TD and DCD-NBP children. From an intervention perspective, the inclusion of regular physical activity, including activities that encourage development of both balance and energy expenditure, may be required to prevent obesity in this population.     

Anxiety profiles in children with and without developmental coordination disorder

Previous work has highlighted that children diagnosed with DCD may be at risk of greater problems related to emotional wellbeing. However, to date much work has relied on population based samples, and anxiety has not been examined within a group of children given a clinical diagnosis of DCD. Additionally, the profile of individual differences has generally not been considered within this group. Therefore, a group of parents (n = 27) completed the parent version of the Spence Children's Anxiety Scale (SCAS-P; Spence, 1998) in relation to their children with a diagnosis of DCD. Their responses on this measure were compared to those of parents with typically developing (TD) children (n = 35; both groups 6-15 years of age). Children diagnosed with DCD were reported to experience significantly greater levels of anxiety overall, as well as having significantly greater difficulty than the TD group in the domains of panic/agoraphobic anxiety, social phobia, and obsessive compulsive anxiety. In addition, the individual profiles of types of anxiety reportedly experienced varied widely across the DCD group. These findings suggest that anxiety is a major problem for a proportion of children diagnosed with DCD, and raises questions regarding intervention, long term outcomes, and the nature of the disorder itself.     

Assessment of physical fitness and exercise tolerance in children with developmental coordination disorder

Children with developmental coordination disorder (DCD) have been shown to be less physically fit when compared to their typically developing peers. The purpose of the present study was to examine the relationships among body composition, physical fitness and exercise tolerance in children with and without DCD. Thirty-seven children between the ages of 7 and 9 years participated in this study. Participants were classified according to results obtained on the Movement Assessment Battery for Children (MABC) and were divided in 2 groups: 19 children with DCD and 18 children without DCD. All children performed the following physical fitness tests: The five-jump test (5JT), the triple-hop distance (THD) and the modified agility test (MAT). Walking distance was assessed using the 6-min walking test (6MWT). Children with DCD showed higher scores than children without DCD in all MABC subscale scores, as well as in the total score (p < 0.001). Participants with DCD were found to perform significantly worse on the MAT (p < 0.001), the THD (p < 0.001) and 5JT (p < 0.05). Moreover, children with DCD had poorer performance on the 6MWT than children without DCD (p < 0.01). Our results found significant correlations among body mass index (BMI), THD (r = 0.553, p < 0.05), 5JT (r = 0.480, p < 0.05) and 6MWT (r = 0.544, p < 0.05) only in DCD group. A significant correlation between MAT and 5JT (r = −0.493, p < 0.05) was found. Similarly, THD and 5JT (r = 0.611, p < 0.01) was found to be correlated in children with DCD. We also found relationships among 6MWT and MAT (r = −0.522, p < 0.05) and the 6MWT and 5JT (r = 0.472, p < 0.05) in DCD group. In addition, we found gender specific patterns in the relationship between exercise tolerance, explosive strength, power, DCD, and BMI. In conclusion, the present study revealed that BMI was indicative of poorer explosive strength, power and exercise tolerance in children with DCD compared to children without DCD probably due to a limited coordination on motor control.     

Left ventricular structure and function in children with and without developmental coordination disorder

Children with developmental coordination disorder (DCD) are more likely to develop cardiovascular disease risk factors such as obesity and reduced cardio-respiratory fitness. However, there is limited data using laboratory measures for assessing the risk of cardiovascular disease associated with DCD. The purpose of this study was to examine differences in left ventricular structure and function between children with DCD and healthy controls. The study involved 126 children (aged 12-13 years) with significant motor impairment (n = 63) and healthy controls (n = 63) matched for age, sex, and school. The Movement ABC test (M-ABC2) was used to classify children as probable DCD (p-DCD). Cardiac dimensions were measured using ultrasound echocardiography. Left ventricular mass (LVM) was elevated in children with p-DCD (89 ± 17 g) compared to controls (87 ± 21 g), however, this difference was not significant. When LVM was normalized to height^2.7, no difference was evident between groups (26 g and 26 g for the p-DCD and controls, respectively). However, the p-DCD group demonstrated significantly elevated stroke volume (p = 0.02), cardiac output (p < 0.001), end-diastolic volume (p = 0.03), and left ventricle diameter in diastole (p = 0.02). Also, peak VO₂ normalized for fat free mass (FFM) was significantly lower (p = 0.001) and systolic blood pressure (p = 0.01), body mass index (p = 0.001), heart rate (p = 0.005) and percent body fat (p < 0.001) were significantly higher in p-DCD. In regression analyses, p-DCD was a significant predictor of stroke volume and cardiac output even after accounting for height, FFM, VO_2FFM, and sex. Children with p-DCD do not demonstrate significantly elevated LVM or depressed systolic function compared to healthy controls. However, cases with p-DCD demonstrate significantly elevated end-diastolic volume, diastolic chamber size, stroke volume, and cardiac output. These differences indicate obesity related changes in the left ventricle and may represent the early stages of developing left ventricle hypertrophy.     

Reduced motor imagery efficiency is associated with online control difficulties in children with probable developmental coordination disorder

Recent evidence indicates that the ability to correct reaching movements in response to unexpected target changes (i.e., online control) is reduced in children with developmental coordination disorder (DCD). Recent computational modeling of human reaching suggests that these inefficiencies may result from difficulties generating and/or monitoring internal representations of movement. This study was the first to test this putative relationship empirically. We did so by investigating the degree to which the capacity to correct reaching mid-flight could be predicted by motor imagery (MI) proficiency in a sample of children with probable DCD (pDCD). Thirty-four children aged 8 to 12 years (17 children with pDCD and 17 age-matched controls) completed the hand rotation task, a well-validated measure of MI, and a double-step reaching task (DSRT), a protocol commonly adopted to infer one's capacity for correcting reaching online. As per previous research, children with pDCD demonstrated inefficiencies in their ability to generate internal action representations and correct their reaching online, demonstrated by inefficient hand rotation performance and slower correction to the reach trajectory following unexpected target perturbation during the DSRT compared to age-matched controls. Critically, hierarchical moderating regression demonstrated that even after general reaching ability was controlled for, MI efficiency was a significant predictor of reaching correction efficiency, a relationship that was constant across groups. Ours is the first study to provide direct pilot evidence in support of the view that a decreased capacity for online control of reaching typical of DCD may be associated with inefficiencies generating and/or using internal representations of action.     

Participation of children with developmental coordination disorder

Children with developmental coordination disorder (DCD) participate less frequently and in less diverse activities compared to typically-developing children. Participation restrictions have been attributed to poor motor skills, but no studies have examined the influence of the environment on participation of children with DCD. This study examined participation in children with DCD at home, school and in the community, considering both personal and environmental factors.Eighty-one parents of 4- to 12-year-old children with DCD (M = 8.3, SD = 2.1) completed the Participation and Environment Measure-Child and Youth (PEM-CY). Our data were compared to previously published data on typically-developing children. Children with DCD participated less frequently than typically-developing children in school and community settings and had less overall environmental support in all three settings. Regarding improvement in participation, children with DCD would benefit from motor interventions that also focus on modification of the environment to support their participation in home, school, and community settings.     

Wisconsin Card Sorting Test performance in children with developmental coordination disorder

The primary purpose of this study was to investigate and compare the executive functions measured by the Wisconsin Card Sorting Test (WCST) between children with developmental coordination disorder (DCD) and age-matched normal controls. A second purpose was to examine the relations between executive functions and school functions in DCD children. Seventy-one children with DCD and 70 children without motor problems were recruited from 14 public schools. Executive functions and school functions were assessed using the WCST, and the School Function Assessment - Chinese Version (SFA-C) respectively. Univariate analyses demonstrated significant between-group differences in five WCST measures. The logistic regression analysis showed differences between two groups on eight SFA-C subscales, and significant correlation between items measured on WCST and SFA-C was also found. The result of the study provides further evidence of impaired sub-domains of executive functions (i.e., mental shifting, flexibility) in children with DCD. The finding also adds to recent investigations into the relationship between executive functions and school functions in DCD. Implications for rehabilitation professionals and recommendations for further research are discussed.     

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.     

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.     

Psychological distress in children with developmental coordination disorder and attention-deficit hyperactivity disorder

This study explored whether or not a population-based sample of children with developmental coordination disorder (DCD), with and without comorbid attention deficit/hyperactivity disorder (ADHD), experienced higher levels of psychological distress than their peers. A two-stage procedure was used to identify 244 children: 68 with DCD only, 54 with ADHD only, 31 with comorbid DCD and ADHD, and 91 randomly selected typically developing (TD) children. Symptoms of depression and anxiety were measured by child and parent report. Child sex and caregiver ethnicity differed across groups, with a higher ratio of boys to girls in the ADHD only group and a slightly higher proportion of non-Caucasian caregivers in the TD group. After controlling for age, sex, and caregiver ethnicity, there was significant variation across groups in both anxiety (by parent report, F(3,235) = 8.9, p < 0.001; by child report, F(3,236) = 5.6, p = 0.001) and depression (parent report, F(3,236) = 23.7, p < 0.001; child report, F(3,238) = 9.9, p < 0.001). In general, children in all three disorder groups had significantly higher levels of symptoms than TD children, but most pairwise differences among those three groups were not significant. The one exception was the higher level of depressive symptoms noted by parent report in the ADHD/DCD group. In conclusion, children identified on the basis of motor coordination problems through a population-based screen showed significantly more symptoms of depression and anxiety than typically developing children. Children who have both DCD and ADHD are particularly at heightened risk of psychological distress.     

Submaximal oxygen cost during incremental exercise in children with developmental coordination disorder

There has been minimal evidence examining the differences in submaximal aerobic power between children with and without probable developmental coordination disorder (pDCD). This is important as most activities of daily living are performed at submaximal levels. The aim of this study was to examine the oxygen cost of work (VO₂) performed during an incremental exercise protocol on a cycle ergometer. Subjects with pDCD (n = 63) were matched for age and gender to 63 typically developing controls (12–13 years of age) using a nested case–control design. Motor coordination was assessed using the Movement Assessment Battery for Children. Children with pDCD had significantly lower VO2 peak values relative to controls (35.0 vs. 42.9 ml/kg/min, p < 0.0001). At the submaximal level, mixed effects modeling demonstrated that, after controlling for relative body fat, and VO₂ peak, children with pDCD had consistently greater oxygen cost (VO₂ ml/kg/min) compared to controls at any given exercise intensity (p = 0.0006). A significant interaction between pDCD and workload indicated that the difference in VO₂ at higher workloads is greater than that at lower workloads (p = 0.0004). Children with pDCD utilize more oxygen to sustain the same submaximal workload. The implication of these findings is that children with pDCD may experience earlier fatigue than well coordinated individuals when engaging in physical activity.     

Physical activity and fitness in children with developmental coordination disorder: a systematic review

Developmental coordination disorder (DCD) is a neurodevelopmental condition characterized by poor motor proficiency that interferes with a child's activities of daily living. Activities that most young children engage in such as running, walking, and jumping are important for the proper development of fitness and overall health. However, children with DCD usually find these activities challenging. A systematic review of the literature was conducted to synthesize the recent available data on fitness and physical activity in children with DCD, and to understand the extent of the differences between children with DCD and their typically developing peers. Systematic searches of electronic databases and reference lists identified 40 peer-reviewed studies meeting the inclusion criteria. These studies were reviewed in terms of: (a) study design, (b) population, (c) assessment tools, (d) measures, and (e) fitness and physical activity outcomes. It has been demonstrated that body composition, cardiorespiratory fitness, muscle strength and endurance, anaerobic capacity, power, and physical activity have all been negatively associated, to various degrees, with poor motor proficiency. However, differences in flexibility were not conclusive as the results on this parameter are mixed. Studies’ limitations and the impact of results on future work are discussed.     

Postural responses to a moving room in children with and without developmental coordination disorder

Children (10 or 11 years old) with and without developmental coordination disorder (DCD) were exposed to imposed optic flow in a moving room. We manipulated the amplitude and frequency of oscillatory room motion, and we evaluated the coupling of standing body sway with room oscillations. The results revealed that standing sway of both children with and without DCD was influenced by room motion. However, children with DCD responded differently than children without DCD to specific combinations of room motion amplitude and frequency. We conclude that DCD can influence a child's use of imposed optic flow for postural control and that these effects are situation-specific rather than being systemic.     

A prospective cohort study comparing workload in children with and without developmental coordination disorder

The purpose of this prospective cohort study was to assess how cardiorespiratory fitness (CRF) of children with probable developmental coordination disorder (DCD) changes over a period of 4.7 years relative to a group of typically developing controls. A school-based sample of children in a large region of Ontario, Canada with 75 out of a possible 92 schools consented to participate. Children enrolled in Grade 4 (mean = 9.9 years, SD = 0.35) at baseline (n = 2278) were followed over the course of 56 months. A total of eight waves of data collection were carried out throughout the study period. The short form of the Bruininks-Oseretsky test of motor proficiency was used to identify children with probable DCD and the maximal speed attained on the Léger 20-m shuttle run to measure CRF. Mixed-effects modeling was used to estimate the change over time in maximal Leger run speed for both groups adjusting for relevant covariates (e.g., gender, BMI, school, activity level, predilection for activity). Children with pDCD had consistently lower maximal run speed relative to controls. The trajectories of run speed in children with probable DCD and those without the disorder differed by gender with pDCD females demonstrating the lowest scores over time. Both genders with probable DCD showed a greater rate of decline in CRF over time relative to the controls. In conclusion, the difference in CRF between children with and without probable DCD is substantial, and it tends to increase over time. This adds to the argument suggesting that interventions intended to improve CRF may be appropriate and necessary for children with motor difficulties.     

Motor imagery is less efficient in adults with probable developmental coordination disorder: Evidence from the hand rotation task

The present study aimed to provide preliminary insight into the integrity of motor imagery (MI) in adults with probable developmental coordination disorder (pDCD). Based on a strong body of evidence indicating that paediatric samples of DCD often experience difficulties engaging MI, we hypothesised that young adults with pDCD would demonstrate similar difficulties. The performance of 12 young adults (19–35 years) with pDCD was compared to 47 age-matched controls on a traditional mental hand rotation task. Mean inverse efficiency scores were generated for each participant by dividing each participant's mean RT by their proportion of correct responses at each of the stimuli presentation conditions. Preliminary analysis revealed that the performance profiles of individuals with pDCD and age-matched controls showed evidence of being constrained by the biomechanical and postural constraints of real movement, suggesting that both groups engaged in an embodied (MI) strategy to complete the task. Despite engaging in a MI strategy, however, young adults with pDCD were nonetheless significantly less efficient when doing so, shown by significant main effects for group on all group efficiency comparisons. Based on the assumption that MI provides insight into the internal ‘neural’ action representation that precedes action, we argue that the less efficient MI performance demonstrated by young adults with pDCD may indicate inefficiencies engaging or implementing internal action representations. Implications and directions for future research are discussed.     

The effect of motor load on planning and inhibition in developmental coordination disorder

Previous research has reported mixed findings regarding executive function (EF) abilities in developmental coordination disorder (DCD), which is diagnosed on the basis of significant impairments in motor skills. The current study aimed to assess whether these differences in study outcomes could result from the relative motor loads of the tasks used to assess EF in DCD. Children with DCD had significant difficulties on measures of inhibition and planning compared to a control group, although there were no significant correlations between motor skills and EF task performance in either group. The complexity of the response, as well as the component skills required in EF tasks, should be considered in future research to ensure easier comparison across studies and a better understanding of EF in DCD over development.