Impact of tactile function on upper limb motor function in children with Developmental Coordination Disorder

This study investigated the presence of, and relationship between tactile dysfunction and upper limb motor function in children with Developmental Coordination Disorder (DCD) compared to typical developing (TD) children. Participants were 36 children aged 6–12 years. Presence of DCD (n = 20) or TD (n = 16) was confirmed using the Movement Assessment Battery for Children, second edition. All children participated in a comprehensive assessment of tactile registration (Semmes Weinstein Monofilaments); tactile spatial perception (Single Point Localisation (SPL) and two-point discrimination (2PD)); haptic perception (Stereognosis); speed of simple everyday manual tasks (Jebsen–Taylor Test of Hand Function (JTTHF)); and handwriting speed and accuracy (Evaluation Tool of Children's Handwriting (ETCH)). Compared to TD children, children with DCD demonstrated poorer localisation of touch in the non-dominant hand (p = 0.04), slower speed of alphabet writing (p < 0.05) and less legible handwriting (p < 0.01), but no difference in speed of simple everyday manual tasks (JTTHF: p > 0.05). Regression analysis showed that spatial tactile perception (SPL) predicted handwriting legibility (ETCH: r = 0.11) and speed of functional tasks (JTTHF: r = 0.33). These results suggest that tactile function, specifically single point localisation, should be a primary tactile assessment employed to determine reasons for upper limb motor difficulties experienced by children with DCD.     

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.     

Aggressive interactions during free-play at preschool of children with and without developmental coordination disorder

This aim of this study was to investigate an unexpected finding from a larger study examining the play of preschool children with and without developmental coordination disorder (DCD). We found that children with DCD were more frequently involved in aggressive incidents during free-play than their peers. Children with (n = 32) and without DCD (n = 31) were videotaped during free-play at preschool and their play was assessed using the Play Observation Scale. A post hoc analysis was conducted using a specifically developed rating instrument to examine the aggressive incidents captured on video. Videos from 18 children with DCD and 8 typically developing children without DCD were found to contain aggressive incidents. Children with DCD were significantly more often involved as both aggressor (p = .016) and victim (p = .008) than children without DCD (p = .031). This is the first study to identify victimization and aggression as being problematic for children with DCD as young as 4 years of age and needs replication. Given the negative consequences of involvement in aggression and victimization, play-based early intervention focusing on prevention needs to be developed and implemented.     

Understanding physical activity and motivations for children with Developmental Coordination Disorder: An investigation using the Theory of Planned Behavior

Developmental coordination disorder (DCD) is a neurodevelopmental condition, affecting approximately 5–6% of children. Previous research has consistently found children with DCD being less physically active compared to typically-developing (TD) children; however, the psychosocial factors associated with physical activity for children with DCD are poorly understood. The purpose of this study was to examine how theory-based physical activity cognitions impacts physical activity behaviors for children with and without DCD. Participants included a sample of boys (N = 61, M_age = 13.25 ± .46) with DCD (n = 19) and without DCD (n = 42), drawn from a larger prospective cohort study. A questionnaire with psychosocial measures was first administered, and accelerometers were used to assess their physical activity behavior over the subsequent week. Findings indicate that DCD was significantly associated with lower physical activity (F(1,58) = 6.51, p < .05), and poorer physical activity cognitions (F(4,56) Wilks Lambda = 2.78, p < .05). Meditational analyses found attitudes (B = .23, p < .05) and subjective norms (B = .31, p < .05) partially mediating the relationship between DCD and physical activity. Overall, this study further confirms that the activity deficit that exists among boys with DCD, and that the relationship is partially mediated through some physical activity cognitions. Interventions should target the perceived approval of influential people, and the personal evaluations of physical activity for boys with motoric difficulties. These findings further emphasizes the discrepancy in physical activity that exist between boys with DCD and TD boys, and highlight the need to better understand the psychological factors related to physical activity for children with DCD.     

The effect of visual therapy on the ocular motor control of seven- to eight-year-old children with Developmental Coordination Disorder (DCD)

The aims of this study were to determine the extent of ocular, motor control problems and the effect of visual therapy on such problems, among seven- to eight-year-old children diagnosed with DCD. Thirty-two, children with a mean age of 95.66 months (SD ± 3.54) participated in the study. The MABC was used to classify children into DCD categories (<15th, percentile) while the Sensory Input Systems Screening Test and QNST-II, were used to evaluate ocular motor control. A two-group pre-test–post-test, cross-over design was followed with a retention test two years, thereafter to determine the lasting effect of the visual therapy, intervention. The 18-week visual therapy programme was executed once a week, for 40 min during school hours, after which the two groups were, crossed over. Percentages of ocular motor control problems ranging, between 6.25% and 93.75% were found in both the groups before participating, in the visual therapy programme, with the highest percentage problems found, in visual pursuit with the left eye. Visual therapy contributed to a, significant improvement of 75–100% in visual pursuit, fixation, ocular, alignment and convergence, with significant lasting effects (p < 0.001). Visual therapy is recommended for children with DCD experiencing poor, ocular motor control.     

Physical fitness and overweight in Israeli children with and without developmental coordination disorder: Gender differences

Physical fitness and overweight among children has become paramount in the general population and more so in children with developmental coordination disorder (DCD). The purpose of the current study was to examine the association between physical fitness and overweight in a sample of Israeli children in comparison to typical children, and to examine gender differences. DCD was identified through total scores on the movement assessment battery for children 2 (MABC-2) equal to or less than the 16th percentile as well as parents’ report that the child's deficits in motor skills interfered with at least two daily life activities. The sample included a group of children with DCD (n = 22, M age = 8.70 [SD = 1.36], 16 boys [73%]) and a control group of typical children (n = 47, M age = 8.90 [SD = 1.52], 34 boys [72%]). Measures included the strength subtest of the Bruininks–Oseretsky test of motor proficiency (BOT-2), the six minutes’ walk test (6MWT) with heart rate measure, BMI and the percentage of body fat. Significant differences between DCD and typical children were found on all variables of physical fitness and weight. A two-way analysis of variance (ANOVA) analysis (group/gender) also revealed significant interactions for the percentage of body fat (F = 8.51, p < .005) and BMI (F = 4.50, p < .038) meaning that less fit children are more obese. The current study supports previous findings that children with DCD are less physically fit and more overweight compared to typically developing children. Moreover, in comparing between the genders, the girls in the study sample weighed more and had a significantly higher percentage of body fat than boys, it is essential to further our understanding of the relationships between obesity, physical fitness and gender among children with and without DCD.     

Slowed muscle force production and sensory organization deficits contribute to altered postural control strategies in children with developmental coordination disorder

This study aimed to (1) compare the postural control strategies, sensory organization of balance control, and lower limb muscle performance of children with and without developmental coordination disorder (DCD) and (2) determine the association between postural control strategies, sensory organization parameters and knee muscle performance indices among children with DCD. Fifty-eight DCD-affected children and 46 typically developing children participated in the study. Postural control strategies and sensory organization were evaluated with the sensory organization test (SOT). Knee muscle strength and time to produce maximum muscle torque (at 180°/s) were assessed using an isokinetic machine. Analysis of variance was used to compare the outcome variables between groups, and multiple regression analysis was used to examine the relationships between postural control strategies, sensory organization parameters, and isokinetic indices in children with DCD. The DCD group had significantly lower strategy scores (SOT conditions 5 and 6), lower visual and vestibular ratios, and took a longer time to reach peak torque in the knee flexor muscles than the control group (p > 0.05). After accounting for age, sex, and body mass index, the vestibular ratio explained 35.8% of the variance in the strategy score of SOT condition 5 (p < 0.05). Moreover, the visual ratio, vestibular ratio, and time to peak torque of the knee flexors were all significant predictors (p < 0.05) of the strategy score during SOT condition 6, accounting for 14, 19.7, and 19.8% of its variance, respectively. The children with DCD demonstrated deficits in postural control strategy, sensory organization and prolonged duration of muscle force development. Slowed knee muscle force production combined with poor visual and vestibular functioning may result in greater use of hip strategy by children with DCD in sensory challenging environments.     

Afferent control of walking: Are there distinct deficits associated to loss of fibres of different diameter?

ObjectivesTo compare the gait pattern in patients affected by different types of neuropathy.MethodsWe recruited healthy subjects (HS, n = 38), patients with Charcot–Marie–Tooth disease type 1A (CMT1A) (n = 10) and patients with diabetic neuropathy (DNP) (n = 12). Neuropathy impairment score and neuropathy score were assessed. Body sway during quiet stance, and spatio-temporal gait parameters were recorded.ResultsMost patients had reduced or absent tendon-tap reflexes. Strength of foot dorsiflexor muscles (p < 0.05) and conduction velocity (CV) of leg nerves (p < 0.0001) were more impaired in CMT1A than DNP, whereas joint-position sense was more affected (p < 0.05) in DNP. Body sway while standing was larger in DNP compared to CMT1A and HS (p < 0.01 and p < 0.0001 respectively). During gait, the distribution of foot sole contact pressure was abnormal in CMT1A (p < 0.05) but not in DNP. Velocity and step length were decreased, and foot yaw angle at foot flat increased, in DNP with respect to CMT1A and HS (both variables, p < 0.001). Gait velocity and step length were decreased (p < 0.005) also in CMT1A, but to a smaller extent than in DNP, so that the difference between patient groups was significant (p < 0.0005). Duration of the double support was protracted in DNP compared to CMT1A and HS (p < 0.0005). For DNP only, velocity of gait and duration of single support were correlated (p < 0.05) both to sway path and lower limb muscle strength.ConclusionsChanges in both body sway and stance phase of gait were larger in DNP than CMT1A, indicating more impaired static and dynamic control of balance when neuropathy affects the small in addition to the large afferent fibres. Diminished somatosensory input from the smaller fibres rather than muscle weakness or foot deformity plays a critical role in the modulation of the support phase of gait.SignificanceThe analysis of balance and gait in patients with neuropathy can offer a tool for understanding the nature and functional impact of the neuropathy and should be included in their functional evaluation.     

Physical fitness in children with Developmental Coordination Disorder: Measurement matters

Children with Developmental Coordination Disorder (DCD) experience considerable difficulties coordinating and controlling their body movements during functional motor tasks. Thus, it is not surprising that children with DCD do not perform well on tests of physical fitness. The aim of this study was to determine whether deficits in motor coordination influence the ability of children with DCD to perform adequately on physical fitness tests. A case–control study design was used to compare the performance of children with DCD (n = 70, 36 boys, mean age = 8y 1mo) and Typically Developing (TD) children (n = 70, 35 boys, mean age = 7y 9mo) on measures of isometric strength (hand-held dynamometry), functional strength, i.e. explosive power and muscular endurance (Functional Strength Measurement), aerobic capacity (20 m Shuttle Run Test) and anaerobic muscle capacity, i.e. muscle power (Muscle Power Sprint Test). Results show that children with DCD were able to generate similar isometric forces compared to TD children in isometric break tests, but were significantly weaker in three-point grip strength. Performance on functional strength items requiring more isolated explosive movement of the upper extremities, showed no significant difference between groups while items requiring muscle endurance (repetitions in 30 s) and items requiring whole body explosive movement were all significantly different. Aerobic capacity was lower for children with DCD whereas anaerobic performance during the sprint test was not. Our findings suggest that poor physical fitness performance in children with DCD may be partly due to poor timing and coordination of repetitive movements.     

Use of the Gait Profile Score for the evaluation of patients with joint hypermobility syndrome/Ehlers–Danlos syndrome hypermobility type

Gait analysis (GA) is widely used for clinical evaluations in various pathological states, both in children and in adults, such as in patients with joint hypermobility syndrome/Ehlers–Danlos syndrome hypermobility type (JHS/EDS-HT). Otherwise, GA produces a large volume of data and there is the clinical need to provide also a quantitative measure of the patient's overall gait. Starting from this aim some global indexes were proposed by literature as a summary measure of the patient's gait, such as the Gait Profile Score (GPS). While validity of the GPS was demonstrated for the evaluation of the functional limitation of children with Cerebral Palsy, no studies have been conducted in patients JHS/EDS-HT. The aim of our study was therefore to investigate the effectiveness of the GPS in the quantification of functional limitation of patients with JHS/EDS-HT. Twenty-one adult (age: 36.1 ± 12.7 years) individuals with JHS/EDS-HT were evaluated using GA and from GA data the GPS was computed. The results evidenced that the GPS value of patients was 8.9 ± 2.6, statistically different from 4.6 ± 0.9 displayed by the control group. In particular, all values of Gait Variable Scores (GVS) which compose the GPS were higher if compared to controls, with the exception of Pelvic Tilt and Foot Progression. The correlations between GPS/GVS and Lower Extremity Functional Scale (LEFS) showed significant relationship between GPS and the item 11 (“Walking 2 blocks”) (ρ = ?0.56; p < 0.05) and 12 (“Walking a mile”) of LEFS (ρ = ?0.76; p < 0.05). Our results showed that GPS and GVS seem to be appropriate outcome measures for the evaluation of the functional limitation during gait of patients with JHS/EDS-HT.     

Developmental Coordination Disorder in children with specific language impairment: Co-morbidity and impact on quality of life

Co-morbidity of Developmental Coordination Disorder (DCD) in children with specific language impairment (SLI) and the impact of DCD on quality-of-life (QOL) was investigated in 65 5–8 year old children with SLI (43 boys, age 6.8 ± 0.8; 22 girls, age 6.6 ± 0.8). The prevalence of DCD was assessed using DSM-IV-TR criteria (American Psychiatric Association (APA), 2000) operationally defined in the clinical practice guideline (CPG): movement ABC scores below 15th percentile, scores on DCDQ and/or MOQ-T below 15th percentile, absence of medical condition according to paediatric-neurological exam. Quality of life (QOL) was measured with the TNO-AZL-Child-Quality-Of-Life (TACQOL) Questionnaire filled out by parents for the SLI group with and without DCD, and compared to a reference group (N = 572; age 6.9 ± 0.9). The TACQOL covers 7 QOL domains: physical, motor, cognitive and social functioning, autonomy, positive and negative moods. Prevalence of DCD in children with SLI was 32.3%. In children with SLI, mean QOL scores were significantly lower in the autonomy, cognitive, social and positive moods domains compared to the reference group. Children with SLI and DCD differed from children with SLI without DCD by significantly lower mean overall-, motor-, autonomy-, and cognitive domain-QOL scores. Clinicians should be aware that about one third of children with SLI can also be diagnosed with DCD. Assessment of QOL is warranted in order to assess which domains are affected in children with SLI with or without DCD.     

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.     

Evaluation of group versus individual physiotherapy following lower limb intra-muscular Botulinum Toxin-Type A injections for ambulant children with cerebral palsy: A single-blind randomized comparison trial

This study aimed to evaluate efficacy of group (GRP) versus individual (IND) physiotherapy rehabilitation following lower limb intramuscular injections of Botulinum Toxin-Type A (BoNT-A) for ambulant children with cerebral palsy (CP). Following lower limb BoNT-A injections, 34 children were randomly allocated to GRP (n = 17; mean age 7y8m SD 2.0; 13 males; Gross Motor Function Classification System (GMFCS) I = 5, II = 8, III = 4) or IND physiotherapy (n = 17; mean age 8y7m SD 2.0; 11 males; GMFCS I = 9, II = 5, III = 3). Primary outcomes were the Canadian Occupational Performance Measure (COPM) and Edinburgh Visual Gait Score (EVGS) assessed at baseline, 10 and 26 weeks post intervention. There were no baseline differences between groups. GRP intervention had greater, but not clinically meaningful, improvement in COPM satisfaction (estimated mean difference EMD 1.7, 95% CI 0.4–3.1; p < 0.01) at 26 weeks. Both groups demonstrated clinically significant improvements in COPM performance and satisfaction, but minimal change in quality of gait (EVGS). Six hours of direct physiotherapy (either GRP or IND) with an additional indirect dose (median 16 episodes) of individualized home programme activities following lower limb BoNT-A injections, however, was inadequate to drive clinically meaningful changes in lower limb motor outcomes.     

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.     

Performance on Functional Strength Measurement and Muscle Power Sprint Test confirm poor anaerobic capacity in children with Developmental Coordination Disorder

BackgroundThere is little and conflicting information about anaerobic performance and functional strength in children with Developmental Coordination Disorder (DCD).AimsTo investigate anaerobic capacity and functional strength in children with a clinical diagnosis of DCD (clin-DCD) and if differences were larger in older (age 7–10 years) compared to younger children (age 4–6 years). Furthermore to determine the percentage of children with clin-DCD that scored <15th percentile on the norm-referenced Functional Strength Measurement.MethodA clin-DCD group (36 boys, 11 girls, mean age: 7y 1mo, SD = 2y 1mo) and a typically developing group (TD) (57 boys, 53 girls, mean age: 7y 5mo, SD = 1y 10mo) were compared on Muscle Power Sprint Test (MPST) and Functional Strength Measurement (FSM).ResultsChildren with clin-DCD performed poorer on the MPST and FSM, especially on the muscle endurance items of the FSM. The differences were larger in the older children compared to the younger on the cluster muscle endurance and the FSM total score. Over 50% of clin-DCD group scored <15th percentile on the FSM.InterpretationDifferences between children with clin-DCD and TD children are even more pronounced in the older children, especially when tested on items requiring fast repetitive movements.     

Altered trunk movements during gait in children with spastic diplegia: Compensatory or underlying trunk control deficit?

Altered trunk movements during gait in children with CP are considered compensatory due to lower limb impairments, although scientific evidence for this assumption has not yet been provided. This study aimed to study the functional relation between trunk and lower limb movement deficits during gait in children with spastic diplegia. Therefore, the relationship between trunk control in sitting, and trunk and lower limb movements during gait was explored in 20 children with spastic diplegia (age 9.2 ± 3 yrs; GMFCS level I n = 10, level II n = 10). Trunk control in sitting was assessed with the Trunk Control Measurement Scale (TCMS), a clinical measure that reflects the presence of an underlying trunk control deficit. Trunk movements during gait were measured with a recently developed trunk model including the pelvis, thorax, head, shoulder line and spine. Lower limb movements were assessed with the Plug-in-Gait model (Vicon®). Range of motion (ROM) of the different trunk segments was calculated, as well as the Trunk Profile Score (TPS) and Trunk Variable Scores (TVSs). Similarly, the Gait Profile Score (GPS) and Gait Variable Scores (GVSs) were calculated to describe altered lower limb movements during gait. Correlation analyses were performed between the presence of impaired trunk control in sitting (TCMS) and altered trunk movements during gait (ROM, TPS/TVSs) and between these altered trunk movements and lower limb movements (GPS/GVSs) during gait. A poorer performance on the TCMS correlated with increased ROM and TPS/TVSs, particularly for the thorax, indicating the presence of an underlying trunk control deficit. No significant correlation was found between the TPS and GPS, suggesting that overall trunk and lower limb movement deficits were not strongly associated. Only few correlations between specific lower limb deficits (GVSs for hip ab/adduction, knee flexion/extension and ankle flexion/extension) and TVSs for thorax lateral bending and rotation were found. This study provided first evidence that the altered trunk movements observed during gait should not be solely considered compensatory due to lower limb impairments, but that these may also partially reflect an underlying trunk control deficit. A better understanding of underlying trunk control deficits in children with CP may facilitate targeted therapy planning and ultimately can optimize a child's functionality.     

Perceived athletic competence and physical activity in children with developmental coordination disorder who are clinically referred,and control children

The relationship between perceived athletic competence (PAC) and physical activity (PA) in children with developmental coordination disorder (DCD) is still unclear. This study investigated differences in PAC and PA between, and within, a group of children with DCD that were clinically referred (n = 31) and a group of control children (n = 38), aged 7–12 years. All children were categorized in four groups: (1) children with DCD/low PAC, (2) children with DCD/normal to high PAC, (3) control children/low PAC, and (4) control children/normal to high PAC. PAC was assessed with the Self-Perception Profile for Children, and PA was assessed with the Modifiable Activity Questionnaire. Children with DCD participated less in unorganized PA, but not in organized PA, compared with control children. Normal to high PAC was found in more than half of the children (64.5%) with DCD. Children with DCD/low PAC and children with DCD/normal to high PAC participated significantly less in unorganized physical activity compared with control children/normal to high PAC, but not compared with control children/low PAC. The results indicate that there are large individual differences in PAC in children with DCD.     

Differential effect of Taekwondo training on knee muscle strength and reactive and static balance control in children with developmental coordination disorder: A randomized controlled trial

This randomized controlled trial aimed to investigate the effect of short-term intensive TKD training on the isokinetic knee muscle strength and reactive and static balance control of children with developmental coordination disorder (DCD). Among the 44 children with DCD (mean age: 7.6 ± 1.3 years) recruited, 21 were randomly assigned to undergo daily TKD training for 1 h over three consecutive months, with the remaining 23 children being assigned to the DCD control group. Eighteen typically developing children (mean age: 7.2 ± 1.0 years) received no training as normal controls. Knee extensor and flexor muscle strength and reactive and static balance control were assessed using an isokinetic machine (with low, moderate and high movement velocities), a motor control test (MCT) and a unilateral stance test (UST), respectively. A repeated measures MANCOVA revealed a significant group through time interaction effect in isokinetic outcomes at 180°/s and in the UST outcome. Post hoc analysis demonstrated that DCD-TKD children's isokinetic knee muscle strength, specifically at 180°/s, was as high as that of the normal control children (p > 0.0083) after TKD training. Moreover, UST body sway velocity was slower in the DCD-TKD group than in the DCD control group (p < 0.001), and was comparable to that of the normal control group (p > 0.05) after TKD training. However, no such improvement in balance was observed in the MCT (p > 0.025). The results show that children with DCD who undergo a 3-month program of intensive TKD training experience improvements in isokinetic knee muscle strength at 180°/s and static single-leg standing balance control, but do not benefit from improved reactive balance control.     

Executive function and attention in young adults with and without Developmental Coordination Disorder – A comparative study

The current research aimed at examining the executive function (EF) of young adults with Developmental Coordination Disorder (DCD) in comparison to young adults without DCD. The study used a randomized cohort (N = 429) of young adults with DCD (n = 135), borderline DCD (n = 149) and control (n = 145), from a previous study. This initial cohort was asked to participate in the current study three to four years later. Twenty-five individuals with DCD (mean age = 24 years, 1 month [SD = 0.88]; 18 males), 30 with borderline DCD (mean age = 24 years, 2 month [SD = 0.98]; 18 males) and 41 without DCD (mean age = 25 years, 2 months [SD = 1.91]; 20 males) participated in this study. Participants completed the BRIEF-A questionnaire, assessing EF abilities and the WURS questionnaire, assessing attention abilities. The DCD and borderline DCD groups had significantly lower EF profiles in comparison with the control group but no significant differences were found between the DCD and borderline DCD groups. While a high percentage of attention problems were found in both DCD groups, the executive functioning profiles remained consistent even when using the attention component as a covariate. The study results suggest that young adults with DCD have EF problems which remain consistent with or without attention difficulties.     

Psychometric properties of the DCD-Q-07 in children ages to 4–6

It is important to identify Developmental Coordination Disorder (DCD) early in a child's life to allow for proper and timely intervention and support, and to reduce the negative secondary consequences associated with this condition. In this study we assessed the psychometric properties (construct validity, concurrent validity, reliability and test accuracy) of the Developmental Coordination Disorder Questionnaire (DCD-Q-07) in preschool children. A community-based sample of children ages 4–6 (n = 181) were screened for motor difficulties using the Movement Assessment Battery for Children (M-ABC-2). Use of the M-ABC-2 resulted in the identification of 29 children below the 15th percentile, which we classified as probable DCD. Parents of these children concurrently completed the DCD-Q-07 to report their child's motor performance. The DCD-Q-07 demonstrated high internal consistency for both the full scale (alpha = 0.881) and each subscale: control during movement (alpha = 0.813), fine motor and handwriting (alpha = 0.869) and general coordination (alpha = 0.728). Moderate correlations (r = 0.47–0.63) were also seen between the subscales on the DCD-Q-07, the strongest correlation being between control during movement and general coordination (r = 0.63). Based on published age and sex cut points, the DCD-Q-07 showed poor sensitivity (20.7%) but high specificity (92.1%) against the M-ABC-2. Overall agreement with the M-ABC-2 was low using ROC analysis (area under the curve = 0.654). Although it is important to screen for DCD in young children, the DCD-Q-07 may not be the best choice as a screening tool for DCD in preschool children ages 4–6 due to its low test accuracy.