Study protocol to examine the effects of acute exercise on motor learning and brain activity in children with developmental coordination disorder (ExLe-Brain-DCD).

INTRODUCTION: Developmental coordination disorder (DCD) is one of the most prevalent pediatric chronic conditions. Without proper intervention, significant delays in motor skill performance and learning may persist until adulthood. Moderate-to-vigorous physical exercise has been proven to improve motor learning (adaptation and consolidation) in children with or without disorders. However, the effect of a short bout of physical exercise on motor adaptation and consolidation in children with DCD has not been examined. Furthermore, the role of perceptual-motor integration and attention as mediators of learning has not been examined via neuroimaging in this population. OBJECTIVES: Therefore, the primary aims of this project will be to compare children with and without DCD to (a) examine the effect of acute exercise on motor learning (adaptation and consolidation) while performing a rotational visuo-motor adaptation task (rVMA), and (b) explore cortical activation in the dorsolateral- and ventrolateral-prefrontal cortex areas while learning the rVMA task under rest or post-exercise conditions. METHODS: One hundred twenty children will be recruited (60 DCD, 60 controls) and within-cohort randomly assigned to either exercise (13-minute shuttle run task) or rest prior to performing the rVMA task. Adaptation and consolidation will be evaluated via two error variables and three retention tests (1h, 24h and 7 days post adaptation). Cortical activation will be registered via functional near-infrared spectroscopy (fNIRS) during the baseline, adaptation, and consolidation. DISCUSSION: We expect to find exercise benefits on motor learning and attention so that children with DCD profiles will be closer to those of children with typical development. The results of this project will provide further evidence to: (a) better characterize children with DCD for the design of educational materials, and (b) establish acute exercise as a potential intervention to improve motor learning and attention.

The self-reported driving and pedestrian behaviour of adults with developmental coordination disorder.

BACKGROUND: Developmental coordination disorder (DCD) affects movement coordination, but little is known about how the condition impacts the behaviours of car drivers and pedestrians. AIMS: This study examined the self-reported driving and pedestrian behaviours of adults with Developmental Coordination Disorder (DCD). METHODS AND PROCEDURES: One hundred and twenty-eight participants (62 adults with DCD vs. 66 TD adults) responded to an online survey asking them about their perceptions of confidence and self-reported driving and pedestrian behaviours in the real-world. OUTCOMES AND RESULTS: Results suggested that adults with DCD felt less confident and reported more lapses in attention (e.g., forgetting where their car was parked) and errors (e.g., failing to check their mirrors prior to a manoeuvre) when driving compared to typically developed (TD) adults. Adults with DCD also reported feeling less confident and reported less adherence to road traffic laws (e.g., not waiting for a green crossing signal before crossing the road) when walking as pedestrians. CONCLUSIONS AND IMPLICATIONS: These results offer some much-needed insight into the behaviours of those with DCD outside of the laboratory environment and underline the need for research investigating the driving and pedestrian behaviours of individuals with DCD in 'real-world' contexts.

Auditory rhythm facilitates perception and action in children at risk for developmental coordination disorder.

Developmental Coordination Disorder (DCD) is a common neurodevelopmental disorder featuring deficits in motor coordination and motor timing among children. Deficits in rhythmic tracking, including perceptually tracking and synchronizing action with auditory rhythms, have been studied in a wide range of motor disorders, providing a foundation for developing rehabilitation programs incorporating auditory rhythms. We tested whether DCD also features these auditory-motor deficits among 7-10 year-old children. In a speech recognition task with no overt motor component, modulating the speech rhythm interfered more with the performance of children at risk for DCD than typically developing (TD) children. A set of auditory-motor tapping tasks further showed that, although children at risk for DCD performed worse than TD children in general, the presence of an auditory rhythmic cue (isochronous metronome or music) facilitated the temporal consistency of tapping. Finally, accuracy in the recognition of rhythmically modulated speech and tapping consistency correlated with performance on the standardized motor assessment. Together, the results show auditory rhythmic regularity benefits auditory perception and auditory-motor coordination in children at risk for DCD. This provides a foundation for future clinical studies to develop evidence-based interventions involving auditory-motor rhythmic coordination for children with DCD.

Activities of daily living, self-efficacy and motor skill related fitness and the interrelation in children with moderate and severe Developmental Coordination Disorder.

BACKGROUND: Children with Developmental Coordination Disorder (DCD) are diagnosed based on poor motor skills that impact their daily activities. However, this may also lead to lower predilection and participation in physical activities and a higher risk to develop health problems. OBJECTIVE: To determine motor skill related levels in children with moderate and severe DCD and compare that to typically developing children (TD). The study also aimed to determine the level of activities of daily living (ADL) as reported by their parent and self-efficacy as reported by the children. Lastly, the relation of motor skill related fitness, ADL, and self-efficacy has been examined. METHODS: A cross-sectional study has compared TD children (n = 105) and children with DCD (n = 109; 45 moderate DCD and 64 severe DCD) from elementary schools in Tunisia between 7 and 10 years of age. The DCDDaily-Questionnaire and Children's Self-perceptions of Adequacy in and Predilection for Physical Activity Questionnaire have been used to determine ADL and adequacy towards physical activity, respectively. The PERF-FIT has been used to measure motor skill related fitness levels. RESULTS: Large group differences (p = 0.001) were found for ADL and all domains of self-efficacy between TD and DCD children. However, ADL and self-efficacy were not different between moderate and severe DCD. Motor skill related fitness was significantly lower (p = 0.01) for children with DCD than TD children, and between children with moderate and severe DCD. The relation between self-efficacy and DCDDaily-Q was different in the two DCD groups. Slow motor learning was associated with lower perceived enjoyment in physical education in the moderate DCD group, and with lower perceived adequacy in physical education in the severe DCD group. CONCLUSIONS: Children with DCD participate and enjoy physical activity less than their peers. This combination of lower participation, lower predilection to physical activity and lowered motor skill-related fitness is a concern for the present and future health status of children with DCD.

Atypical procedural learning in children with developmental coordination disorder: A combined behavioral and neuroimaging study.

While procedural learning (PL) has been implicated in delayed motor skill observed in developmental coordination disorder (DCD), few studies have considered the impact of co-occurring attentional problems. Furthermore, the neurostructural basis of PL in children remains unclear. We investigated PL in children with DCD while controlling for inattention symptoms, and examined the role of fronto-basal ganglia-cerebellar morphology in PL. Fifty-nine children (6-14 years; nDCD = 19, ncontrol = 40) completed the serial reaction time (SRT) task to measure PL. The Attention-Deficit Hyperactivity Disorder Rating Scale-IV was administered to measure inattention symptoms. Structural T1 images were acquired for a subset of participants (nDCD = 10, ncontrol = 28), and processed using FreeSurfer. Volume was extracted for the cerebellum, basal ganglia, and frontal regions. After controlling for inattention symptoms, the reaction time profile of controls was consistent with learning on the SRT task. This was not the case for those with DCD. SRT task performance was positively correlated with cerebellar cortical volume, and children with DCD trended towards lower cerebellar volume compared to controls. Children with DCD may not engage in PL during the SRT task in the same manner as controls, with this differential performance being associated with atypical cerebellar morphology.

Finger counting to relieve working memory in children with developmental coordination disorder: Insights from behavioral and three-dimensional motion analyses.

A limited number of studies have attempted to understand how motor deficits affect numerical abilities in children with developmental coordination disorder (DCD). The purpose of this study was to explore the functionality of finger-counting (FC) in children with DCD. The participants, 15 children with DCD and 15 typically developing (TD) children matched on school level and fluid reasoning abilities, were asked to use FC to solve an ordinal task with high working memory (WM) load. Behavioral measures supplemented with biomechanical measures, from three-dimensional motion analysis synchronized to a voice recording were used to assess children's performance and FC functionality (total duration, inter-finger [IF] transition, IF variance, finger/voice synchronization, and automatization of FC movements). Children with DCD were less accurate than TD children in using FC to solve ordinal problems with high WM load. This group difference could not be accounted for by poor FC skills given that FC movement turned out to be as functional in children with DCD as in their TD peers. When added to the model as a covariate, WM captured a greater proportion of intergroup variability than manual dexterity, further suggesting that their difficulties would be better accounted for by limited WM resources than by fine motor skills.

Motor networks in children with autism spectrum disorder: a systematic review on EEG studies.

Motor disturbance and altered motor networks are commonly reported in individuals with autism spectrum disorder (ASD). It has been suggested that electroencephalogram (EEG) can be used to provide exquisite temporal resolution for understanding motor control processes in ASD. However, the variability of study design and EEG approaches can impact our interpretation. Here, we conducted a systematic review on recent 11 EEG studies that involve motor observation and/or execution tasks and evaluated how these findings help us understand motor difficulties in ASD. Three behavior paradigms with different EEG analytic methods were demonstrated. The main findings were quite mixed: children with ASD did not always show disrupted neuronal activity during motor observation. Additionally, they might have intact ability for movement execution but have more difficulties in neuronal modulation during movement preparation. We would like to promote discussions on how methodological selections of behavioral tasks and data analytic approaches impact our interpretation of motor deficits in ASD. Future EEG research addressing the inconsistency across methodological approaches is necessary to help us understand neurophysiological mechanism of motor abnormalities in ASD.

Impaired wrist position sense is linked to motor abnormalities in young adults with a probable developmental coordination disorder.

Proprioceptive deficits have been found to underlie motor abnormalities in individuals with movement disorders. This study investigated wrist proprioceptive acuity in young adults with and without probable developmental coordination disorder (DCD) and examined how proprioceptive acuity is linked to different domains of motor function. Thirty participants were included in this study (age, 19-22 years), ten with probable DCD and 20 controls. Wrist proprioceptive acuity was assessed using a joint position sense paradigm under contralateral and ipsilateral conditions. The Bruininks - Oseretsky Test of Motor Proficiency 2nd Edition (BOT-2) was used to measure different domains of motor ability. Compared to the control group, young adults with probable DCD exhibited significantly increased proprioceptive error variability in contralateral (p < 0.0001) and ipsilateral conditions (p < 0.05). Furthermore, wrist proprioceptive error variability was significantly associated with the levels of body coordination measured by BOT-2 (r = - 0.55). This study verified impaired wrist proprioceptive function in young adults with probable DCD, which is likely to contribute to motor impairment in adults with DCD.

Convergent validity of the developmental coordination disorder checklist using soft neurological signs.

AIMS: To investigate the convergent validity of a new questionnaire, the Developmental Coordination Disorder Checklist (DCDC), we examined the relationship between the DCDC score and Soft Neurological Signs (SNS) which highly correlated with the Movement Assessment Battery for Children (MABC), which is widely applied to assess fine and gross motor skills. METHODS: The patients were 70 elementary school children without intellectual disabilities who were referred to our clinic, examined for SNS, and whose parents completed the DCDC. The DCDC consists of 16 items that focus on three factors: fine motor, gross motor, and catch and throw. We used a previously described method to assess SNS, which included five tasks: (1) standing on one leg with closed eyes, (2) finger opposition test, (3) diadochokinesis, (4) associated movements during diadochokinesis, and (5) motor persistence (laterally fixed gaze). RESULTS: DCDC scores and SNS were strongly and positively correlated, with higher DCDC scores (indicating greater coordination problems) associated with a higher number of positive SNS. CONCLUSIONS: DCDC scores have been proven to be strongly correlated with SNS, and these data suggest that DCDC has good convergent validity.

Motor performance and daily participation in children with and without probable developmental coordination disorder.

AIM: To test the mediating role of motor performance in the relationship between individual and environmental constraints, delayed learning of activities of daily living (ADL), and daily participation in typically developing children and children with probable developmental coordination disorder (DCD). METHOD: Parents of 370 randomly selected children aged 5 to 10 years (194 females; mean age [SD] 7y 5mo [1y 10mo]) were included in the study (321 typically developing, 49 probable DCD). Motor performance, ADL learning, and participation were assessed using the DCDDaily-Questionnaire. Individual variables included child's age and sex, and environmental variables included mother and family educational level, presence of siblings, and area of residence. Direct, indirect, and mediating effects were tested using a partial least squares-based structural equation modelling approach. RESULTS: The model explained 44.5% of the variance of daily participation. Motor performance significantly mediated the effect of individual and environmental constraints, and ADL learning on daily participation. INTERPRETATION: Results suggest that the effect of individual and environmental constraints and delayed learning of ADL on daily participation is mediated by motor performance in typically developing children and children with probable DCD. These findings provide further evidence that interventions to promote participation in children with probable DCD should adopt ecological, task-oriented approaches. Further studies should evaluate model generalizability with clinical samples.

Intrahemispheric EEG: A New Perspective for Quantitative EEG Assessment in Poststroke Individuals.

The ratio between slower and faster frequencies of brain activity may change after stroke. However, few studies have used quantitative electroencephalography (qEEG) index of ratios between slower and faster frequencies such as the delta/alpha ratio (DAR) and the power ratio index (PRI; delta + theta/alpha + beta) for investigating the difference between the affected and unaffected hemisphere poststroke. Here, we proposed a new perspective for analyzing DAR and PRI within each hemisphere and investigated the motor impairment-related interhemispheric frequency oscillations. Forty-seven poststroke subjects and twelve healthy controls were included in the study. Severity of upper limb motor impairment was classified according to the Fugl-Meyer assessment in mild/moderate (n = 25) and severe (n = 22). The qEEG indexes (PRI and DAR) were computed for each hemisphere (intrahemispheric index) and for both hemispheres (cerebral index). Considering the cerebral index (DAR and PRI), our results showed a slowing in brain activity in poststroke patients when compared to healthy controls. Only the intrahemispheric PRI index was able to find significant interhemispheric differences of frequency oscillations. Despite being unable to detect interhemispheric differences, the DAR index seems to be more sensitive to detect motor impairment-related frequency oscillations. The intrahemispheric PRI index may provide insights into therapeutic approaches for interhemispheric asymmetry after stroke.

Decline in gross motor skills in adult Rett syndrome; results from a Danish longitudinal study.

Longevity of individuals with neurodevelopmental diseases as Rett syndrome (RTT) has increased and many reach adulthood and old age. There is therefore a need to increase knowledge about the course of RTT in adults in order to improve medical care management and quality of life. We did a longitudinal study to address if a possible decline in motor skills in adults with RTT can be explained by the presence of common medical conditions as epilepsy, breathing disturbance, and scoliosis. Data from the Danish RTT database, medical files, and videos from visits at the national Center for Rett syndrome were reviewed. The study included 24 individuals aged 30-66 years at last visit after a follow-up period of 6-12 years. Results showed a clinically observable and significant decline in gross motor skills using the Rett syndrome Gross Motor Scale (RSGMS) with a tendency of less decline in the individuals with the best motor abilities. The frequencies of comorbidities were high. Decline in RSGMS score was associated with the presence of epilepsy and severe scoliosis that had been conservatively managed. The results emphasize that epilepsy plays a significant role in the adult RTT life and management of severe scoliosis in the younger years has impact on the motor abilities in adulthood.

Attentional and executive functions in children and adolescents with developmental coordination disorder and the influence of comorbid disorders: A systematic review of the literature.

Developmental coordination disorder (DCD) is a neurodevelopmental disorder affecting primarily motor skills, but attentional and executive impairments are common in affected individuals. Moreover, the presence of neurodevelopmental comorbidities is frequent in this population, which certainly influences the cognitive profile of the children concerned. Previous studies have reported deficits in visuospatial/nonverbal and planning tasks. This systematic review of the literature aims to determine if impairments can be found in other attentional and executive functions as well. The type of cognitive tasks, the tasks' modality (verbal/nonverbal), and the influence of comorbid disorders on attentional and executive profiles are systematically considered. Forty-one studies were identified through the PubMed/Medline and PsycINFO databases according to pre-established eligibility criteria. The results reveal weaknesses in inhibitory control, working memory, planning, nonverbal fluency, and general executive functioning in children with DCD. The presence of comorbid disorders seemingly contributes to the verbal working memory difficulties findings. This review contributes to a better understanding of the cognitive impairments in DCD and of the needs of children with this disorder, allowing to optimize practitioners' therapeutic interventions.

Movement performance and movement difficulties in typical school-aged children.

INTRODUCTION: Developmental Coordination Disorder (DCD) is an impairment of executive motor skills. Children aged 7-10 years gradually develop effective movement that enables smooth performance in various daily self-care, academic and sport activities. The purpose of this study was to examine whether the Movement Assessment Battery for Children-Second Edition-Age Band 2, (MABC2-AB2), which is a western standardized test, could be used in Thai children for differentiating between movement performance and movement difficulties. METHOD: Three hundred and sixty typical Thai children aged 7-10 years old were recruited from three primary schools in Chiang Mai district, Thailand. The participants were divided into four age groups and tested using the Movement Assessment Battery for Children-Second Edition-Age Band 2-Thai version (MABC2-AB2-T). RESULTS: Manual Dexterity, Aiming and Catching, and Balance rose with age increment. Older participants had better movement performance than younger ones. The results showed that 91.11 percent of the participants had typical movement, while 3.61 and 5.28 percent of them had movement difficulty and movement at risk, respectively. In addition, three test items: Drawing Trail, Walking Heel to Toe Forward, and Hopping on Mats had a ceiling effect when used for Thai children. CONCLUSION: The MABC2-AB2-T could be used to assess movement performance and movement difficulties in Thai children. About 9 percent of typical Thai children aged 7-10 years old needed early intervention. Administration of the three test items may need to be revised.

Mental rotation performance in young adults with and without developmental coordination disorder.

While there have been consistent behavioural reports of atypical hand rotation task (HRT) performance in adults with developmental coordination disorder (DCD), this study aimed to clarify whether this deficit could be attributed to specific difficulties in motor imagery (MI), as opposed to broad deficits in general mental rotation. Participants were 57 young adults aged 18-30 years with (n = 22) and without DCD (n = 35). Participants were compared on the HRT, a measure of MI, and the letter number rotation task (LNRT), a common visual imagery task. Only participants whose behavioural performance on the HRT suggested use of a MI strategy were included in group comparisons. Young adults with DCD were significantly less efficient compared to controls when completing the HRT yet showed comparable performance on the LNRT relative to adults with typical motor ability. Our data are consistent with the view that atypical HRT performance in adults with DCD is likely to be attributed to specific difficulties engaging in MI, as opposed to deficits in general mental rotation. Based on the theory that MI provides insight into the integrity of internal action representations, these findings offer further support for the internal modelling deficit hypothesis of DCD.

Reliance on visual feedback from ocular accommodation on motor skills in children with developmental coordination disorder and typically developing controls.

Children with developmental coordination disorder (DCD) present with marked impairments in motor skills, including visual-motor integration. Oculomotor anomalies are more prevalent in children with DCD than typically developing children. Children with DCD further demonstrate altered use of visual feedback compared to typically developing controls. We investigated whether the accommodation system, a key component of the oculomotor system, contributes to visual feedback during fine and gross motor skills performance; and whether children with DCD demonstrate differences in reliance on visual feedback from accommodation. Minus dioptre lenses were used to maximally induce accommodation and impede accommodation dynamics. Children with DCD and typically developing controls performed motor skills tests assessing balance, upper limb coordination, visual-motor performance, gross and fine dexterity. Motor skills performance in controls was significantly affected by impeded accommodation in all tasks. Children with DCD demonstrated reliance on accommodation feedback in upper limb and visual-motor tasks only. Children with DCD may be less reliant on visual feedback obtained from accommodation due to adaptive mechanisms to overcome faulty information in the presence of oculomotor anomalies. These results strengthen our previous findings that accommodation anomalies contribute to motor skills impairment, and suggest that performance on these motor tasks is heavily reliant on visual feedback from accommodation.

Effect of comorbid developmental dyslexia on oculomotor behavior in children with developmental coordination disorder: A study with the Developmental Eye Movement test.

Studies have suggested a dysfunction in oculomotor skills in children with developmental coordination disorder (DCD). It has been proposed that the Developmental Eye Movement (DEM) test is useful in testing the dyslexics' (DD) oculomotor behavior during reading, in a simple and indirect manner. The present study aimed at exploring the oculomotor behavior in children with DCD as assessed with the DEM test. We thus compared children with DCD to children with DD and to children with both DCD and DD in order to investigate the specificity of the oculomotor difficulties, as measured by the DEM test. Results showed that 1) children with DCD presented mild atypical performance at the DEM test (error z-score only), 2) children with DD presented particularly poor performance at the DEM test, and 3) the co-morbid condition (DCD + DD) did not add to the severity of atypical performance at the DEM test. In sum, children with DCD were the less affected according to the DEM test, and children with DD (isolated or comorbid) presented the most atypical performance. Results at the DEM test did not allow to highlight clear oculomotor atypicalities in DCD. We thus concluded that more research using eye-tracking techniques is needed to explore the nature of oculomotor atypicalities in DCD children, to distinguish DD and DCD oculomotor behavior, and to understand the profile of children with dual diagnosis.

Motor deficits at presentation and predictors of overall survival in central nervous system lymphomas.

PURPOSE: Central nervous system lymphomas (CNSL) can present with motor and non-motor symptoms. In many central nervous system tumors, motor deficits are associated with significant morbidity and functional impairment, and correlate with worse prognosis. CNSLs however, often exhibit remarkable response to chemotherapy and radiotherapy with corresponding symptom improvement. We investigate the survival outcomes and trajectories of motor and functional recovery in a cohort of patients presenting with and without initial motor deficits. METHODS: Patients who underwent biopsy and with a histologically confirmed CNSL between 2008 and 2019 were retrospectively identified. Baseline demographic variables, comorbidities, presenting symptoms, histological type, neuroimaging features (location and number of lesions), and treatment administered (pre- and post-operative steroid use and chemotherapy regime) were recorded. Dates of death were obtained from the National Registry of Births and Deaths. Motor power and performance status at admission, 1 month and 6 months were determined. RESULTS: We identified 119 patients, of whom 34% presented with focal motor deficits. The median overall survival (OS) was 26.6 months. Those with focal motor deficits had longer OS (median 42.4 months) than those without (median 23.3 months; p = 0.047). In multivariate Cox analysis, age (HR 1.04 per year; p = 0.003), CCI (HR 1.31 per point; p < 0.001), leptomeningeal/ependymal involvement (HR 2.53; p = 0.016), thalamus involvement (HR 0.34; p = 0.019), neutrophil:lymphocyte ratio (HR 1.06 per point; p = 0.034), positive HIV status (HR 5.31; p = 0.003), preoperative steroids use (HR 0.49; p = 0.018), postoperative high-dose steroids (HR 0.26; p < 0.001) and postoperative low-dose steroids (HR 0.28; p = 0.010) were significant predictors of OS. By one month, 43% of surviving patients had full power, increasing to 61% by six months. CONCLUSION: A significant proportion of patients with initial motor deficits recovered in motor strength by six months. In our population, those presenting with motor deficits had paradoxically better overall survival.

Strength, Motor Skills, and Physical Activity in Preschool-Aged Children Born Either at Less Than 30 Weeks of Gestation or at Term.

OBJECTIVE: Children born <30 weeks of gestation have more motor impairment than do children born at term (37-42 weeks gestation), but reported outcomes have largely focused on cerebral palsy and developmental coordination disorder. The aim of this study was to compare muscle strength, motor skills, and physical activity (PA) of preschool-aged children born <30 weeks with those born at term. METHODS: In this cohort study, 123 children born <30 weeks and 128 born at term were assessed. Children were aged ≥4 years, 0 months and <6 years, 0 months' corrected age at the time of the assessment. Outcomes included grip strength (kg), Movement Assessment Battery for Children 2nd edition (MABC-2), Little Developmental Coordination Disorder Questionnaire, accelerometer-measured PA, and a parent-completed PA diary. Linear regression and mixed effects models were used to examine differences between children born <30 weeks and those born at term. RESULTS: Children born <30 weeks had poorer grip strength (preferred hand; mean difference [95% CI] -0.60 kg [-1.04 to -0.15]) and poorer motor competence (Movement Assessment Battery for Children 2nd edition standard score mean difference -2.17 [-3.07 to -1.27]; Little Developmental Coordination Disorder Questionnaire total score mean difference -5.5 [-9.2 to -2.8]) than term-born children. Children born <30 weeks also completed fewer minutes of accelerometer-measured PA (mean difference -41 minutes [-62 to -20]), more minutes of accelerometer-measured stationary behavior (mean difference 33 minutes [12 to 54]), and more minutes of parent-reported screen time (mean difference 21 minutes [10 to 32]) per day. CONCLUSION: Preschool-aged children born <30 weeks had poorer muscle strength, motor skills, and PA levels than term-born children. These findings suggest that preschool-aged children born <30 weeks may benefit from enhanced surveillance and PA promotion to improve life-long health outcomes. IMPACT: In our study, children born <30 weeks had reduced muscle strength and poorer motor skills, participated in less PA, and had more stationary and screen behavior than term-born children. These findings emphasize that awareness of multidomain motor deficits in children born <30 weeks' gestation is needed in clinical practice. Given the associations between higher PA and health benefits and the recognition that PA levels can track from early childhood into adulthood, our study highlights the need for assessment and promotion of PA in preschool-aged children born <30 weeks' gestation. Lay Summary. Preschool-aged children born <30 weeks' gestation have poorer strength, motor skills, and physical activity behaviors than their term-born peers. Clinicians and early childhood educators should recognize that the preschool period is a critical time for the assessment and promotion of PA in children born <30 weeks.

The degree of stability in motor performance in preschool children and its association with child-related variables.

Understanding the stability of individual differences in motor performance during the early years of life, despite normative age-related growth in motor performance, has important implications for identification of motor coordination difficulties and subsequently, early remediation. Therefore, the aims of the present study were to examine the degree of rank-order and individual-level stability in motor performance in young children with different levels of motor skill proficiency. Subsequently, we explored the influence of child variables (i.e., age, gender, and behavioural self-regulation) on different aspects of stability. In this longitudinal study, a community sample of 68 participants (49% girls) with a mean age of 3 years and 11 months (SD = 7 months) were assesses in three six-monthly waves. The total standard score of the Movement Assessment Battery for Children-2 (MABC-2) was used as the measure of motor performance. Rank-order stability was examined with zero-order Pearson correlations. Individual-level stability was examined by means of stability in classifications (at risk for motor coordination difficulties versus typically developing). In addition to examining stability in group classification, the Reliable Change Index (RCI) was calculated to examine if the difference in a child's scores over time exceeded (increased or decreased relative to) the expected change. The results showed moderate to high rank-order stability between time points. No significant differences in degree of rank-order stability were found between boys and girls and between 3-year old and 4-year old children. In terms of stability of classification, it was shown that for ~50% of the children with motor coordination difficulties and ~ 90% of typically developing the classification based on the cut-off score on the MABC-2 was stable. Based on the RCI, over 90% showed individual-level stability. The level of behavioural self-regulation at T1 (as measured with the Head-Toes-Knees-Shoulders task) was not significantly related to individual-level stability in motor performance. In conclusion, our findings highlight the importance of a careful choice of stability measures and a reflection on the implications of their results. More research is needed to understand which child and environmental variables impact on stability.