Handedness and developmental coordination disorder in Portuguese children: Study with the M-ABC test

This study aimed to examine the probable developmental coordination disorder (DCD) and to identify differences in motor performance according to handedness, sex and age in typically developing Portuguese children not engaged in out-of-school sports. The Movement Assessment Battery for Children (M-ABC) was applied to a convenience sample of 154 right-handed and 119 left-handed children (n = 273), aged 4–12 (mean age = 7.96 years, SD = 2.38). The results suggest that the occurrence rate of probable DCD was 25.3% for right-handers and 36.1% for left-handers. This study showed a significant effect of handedness in age band 2, left-handers exhibited a higher prevalence of probable DCD than right-handers. Sex produced a significant effect, with girls performing better in manual dexterity in age band 1 and boys performing better in ball skills in age bands 2 and 3. The lower motor performances were observed in older children. These findings reinforce for Portuguese children and particularly for left-handers, the need for further investigation involving longitudinal studies and children of different handedness in the motor coordination domain. Moreover, we highlight the importance of developing physical education programmes that emphasize motor coordination parameters, especially in left-handed children.     

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.     

Self-Regulatory Skill Among Children with and without Developmental Coordination Disorder: An Exploratory Study

Aim: Children with developmental coordination disorder (DCD) experience difficulty learning and performing everyday motor tasks due to poor motor coordination. Recent research applying a cognitive learning paradigm has argued that children with DCD have less effective cognitive and metacognitive skills with which to effectively acquire motor skills. However, there is currently limited research examining individual differences in children's use of self-regulatory and metacognitive skill during motor learning. This exploratory study aimed to compare the self-regulatory performance of children with and without DCD. Methods: Using a mixed methods approach, this study observed and compared the self-regulatory behavior of 15 children with and without DCD, aged between 7 and 9 years, during socially mediated motor practice. Observation was conducted using a quantitative coding scheme and qualitative analysis of video-recorded sessions. This paper will focus on the results of quantitative analysis, while data arising from the qualitative analysis will be used to support quantitative findings. Results: In general, findings indicate that children with DCD exhibit less independent and more ineffective self-regulatory skill during motor learning than their typically developing peers. In addition, children with DCD rely more heavily on external support for effective regulation and are more likely to exhibit negative patterns of motivational regulation. Conclusions: These findings provide further support for the notion that children with DCD experience difficulty effectively self-regulating motor learning. Implications for practice and directions for future research are discussed.     

Postural coordination modes and transition: dynamical explanations

While research to date has been successful in quantifying postural behaviour, this paper examines the causes of transition between postural coordination mode using dynamical variables and, by inference, efficient control strategies underlying postural behaviour. To this end, six subjects in bipedal stance were instructed to maintain a constant distance between their head and a visual target that oscillated along the line of sight. Within sessions, participants were exposed to gradual changes in increasing target motion frequency. Kinematic results showed a sudden transition between in-phase and anti-phase postural coordination modes in visual target tracking. The dynamical analysis pointed out that (1) the center of pressure (CoP) position parameter is a crucial parameter in the determination of the adopted coordination mode, (2) the change occurred in response to limits bordered by the system: the interaction between equilibrium constraints (A/P displacements of CoP), physiological limits (net joint moments) support the emergence of different postural behaviours and, (3) finally, the anti-phase mode presents a better distribution of muscular moment between hip and ankle joints and is more effective to achieve high frequency oscillations with limited CoP displacements.     

Effects of nitric oxide on expressions of nitrosocysteine and calcium-activated potassium channels in the supraoptic nuclei and neural lobe of dehydrated rats

Using a rhythmic isometric force production paradigm, we investigated the after-effects of in-phase and antiphase bimanual performance on the unintended recruitment of the homologous muscles of the opposite limb during subsequent performance of tasks that were unimanual by design. Electromyograms obtained from the muscles of the opposite limb were analyzed in terms of their amplitude and the distribution of their phase relative to that of the intended movements. Preceding bimanual activity had distinct effects on the relative phase (mean and uniformity) of the structured electromyograms. These were particularly pronounced following performance of the in-phase pattern. These findings are discussed in terms of interhemispheric excitation and inhibition.     

Functional asymmetries in the stepping response of the human newborn: a kinematic approach

In order to investigate subtle expressions of functional asymmetries in newborn leg movements, kinematic registrations were made on a sample of 40 healthy fullterm newborn infants during performance of the stepping response. Time-position data were collected from markers attached to the hip, knee and ankle joints of the left and right leg, and movements of both legs recorded simultaneously. Findings included evident side differences in terms of smoother trajectories of the right leg as a consequence of less movement segmentation compared to the left leg. Additionally, analyses of intralimb coordination revealed side differences with regard to stronger ankle-knee couplings and smaller phase shifts in the right leg. The findings suggest that asymmetries in newborn stepping responses are present in terms of spatio-temporal parameters and intralimb coordination. No evidence of a lateral preference in terms of frequency of the first foot moved was found. The present study adds new understanding to the lateralized attributes of the stepping response in the human newborn and as such points to new directions of research on the nature of laterality in the future.     

1/f β fluctuations in bimanual coordination: an additional challenge for modeling

We analyzed the correlation structure of discrete relative phase (DRP) series in bimanual in-phase and anti-phase coordination by associating a number of fractal methods and using discrete rather than continuous relative phase measurement. ARFIMA/ARMA modeling provided statistical evidence for the presence of long-range correlation, and the series were unambiguously characterized as 1/f ^β noise. Diverging accounts of bimanual coordination are defended in the literature. Since the evidence for 1/f ^β noise provides new insight into the properties of stability in coordination, it should be considered as an empirical criterion for determining which mechanisms are likely to be engaged in bimanual coordination models. We discussed some implications for studying the neural basis of coordination, and we tested the performance of three current models in accounting for 1/f ^β noise in DRP. None of these models was proven to generate the expected correlation structure.     

小脑顶核电刺激治疗小儿中枢性协调障碍的研究

目的：探讨小脑顶核电刺激治疗在小儿中枢性协调障碍康复治疗中的优势。方法选取2012年8月至2013年7月收治的84例中枢性协调障碍患儿随机分为观察组（42例）和对照组（42例）,对照组仅采用常规康复综合治疗,观察组在此基础上加用小脑顶核电刺激疗法,对两组患儿治疗后总有效率及Gesell发育量表动作能之发育商（DQ）进行比较。结果观察组显效率（83.33%）高于对照组（57.14%）,治疗后DQ评分观察组[（84.91±7.28）分]明显高于对照组[（71.97±5.74）分],差异均有统计学意义（P〈0.05）。结论常规康复治疗联合小脑顶核电刺激治疗小儿中枢性协调障碍疗效显著。     

Walking speed best explains perceived locomotion ability in ambulatory people with chronic stroke,assessed by the ABILOCO questionnaire

BackgroundThe identification of the predictors of locomotion ability could help professionals select variables to be considered during clinical evaluations and interventions.ObjectiveTo investigate which impairment measures would best predict locomotion ability in people with chronic stroke.MethodsIndividuals (n = 115) with a chronic stroke were assessed. Predictors were characteristics of the participants (i.e. age, sex, and time since stroke), motor impairments (i.e. muscle tonus, strength, and motor coordination), and activity limitation (i.e. walking speed). The outcome of interest was the ABILOCO scores, a self-reported questionnaire for the assessment of locomotion ability, designed specifically for individuals who have suffered a stroke.ResultsAge, sex, and time since stroke did not significantly correlate with the ABILOCO scores (−0.07 < ρ < 0.05; 0.48 < p < 0.99). Measures of motor impairments and walking speed were significantly correlated with the ABILOCO scores (−0.25 < r < 0.57; p < 0.001), but only walking speed and strength were kept in the regression model. Walking speed alone explained 35% (F = 55.5; p < 0.001) of the variance in self-reported locomotion ability. When strength was included in the model, the explained variance increased to 37% (F = 31.4; p < 0.001).ConclusionsWalking speed and lower limb strength best predicted locomotion ability as perceived by individuals who have suffered a stroke.