Development of motor imagery ability in children with developmental coordination disorder – A goal-directed pointing task

Children with developmental coordination disorder (DCD) have difficulties with the predictive control of movements. This was shown in studies that target motor imagery and motor planning, and appears to become particularly evident with increases in task complexity. In this study, we used a complex mental chronometry paradigm to examine the development of motor imagery ability in children with DCD, using a longitudinal design. Thirty children were included in the DCD group (aged 6–11 years) and age- and gender-matched to 30 controls. The DCD group had a Movement Assessment Battery for Children-2 score ≤16th percentile and the control group ≥25th percentile. Results of this study showed that children with DCD indeed had a significantly lower correlation between executed and imagined movements. Importantly, the increase in the correlation and linear fit during subsequent measurements was comparable for the DCD and control group. Together, these findings suggest a delayed developmental onset of motor imagery ability in DCD, but a similar rate of development over time compared to the control group. Based on these results, it seems likely that explicit motor imagery instructions can be used to improve predictive control in children with DCD.     

发展性协调障碍与书写困难个案研究

该研究对一个14岁书写困难儿童zl的动作和认知技能进行了系统的考察。zl的书写困难主要表现在以下几方面：书写速度慢,字与字之间的空间距离非常近,字迹难以辨认,笔画顺序混乱。该研究首先测查了zl的基本智能和一系列精细动作技能、视觉、视空以及序列加工能力。结果发现他的基本智能、视觉加工能力正常,动作技能和视空加工能力皆显著落后于控制组儿童。语言能力测试发现,他的识字量、阅读理解和听力理解均正常。他在汉字单字、双字词、数字和图片命名上的正确率与控制组没有显著差异,但命名速度明显慢于控制组。神经生理检查发现,他的脑电波轻度异常,核磁共振扫描(MRI)显示双侧脑室体后部和枕角周围白质和小脑发育异常。这些结果表明该儿童的书写困难是更广泛的动作协调障碍的一种体现,并可能以他的脑神经发育状况为基础。文章讨论了zl书写障碍的认知神经机制及对书写障碍早期鉴别和训练的意义。     

Movement Control Strategies in a Dynamic Balance Task in Children With and Without Developmental Coordination Disorder

Abstract

Our study aimed to analyze movement control strategies using predefined criteria for amplitude and differences in these strategies between children with and without DCD. Children with (n?=?28) and without DCD (n?=?15) were included. A video-observation-tool was used to score the moving body parts during a Wii Fit slalom task over multiple time points. Two-step cluster analysis was used to extract distinct movement strategies. Two different movement strategies were identified that were independently validated by a measure of task performance and a subjective mark of quality of the movement. Initial differences between groups and changes over time toward the more successful strategy were found in both groups, albeit in a different percentage. This study shows that the more efficient movement strategy is seen in the majority of the TD children and only in a small number of children with DCD, even after practice.     

Informational constraints on spontaneous visuomotor entrainment

Past research has revealed that an individual’s rhythmic limb movements become spontaneously entrained to an environmental rhythm if visual information about the rhythm is available and its frequency is near that of the individual’s movements. Research has also demonstrated that if the eyes track an environmental stimulus, the spontaneous entrainment to the rhythm is strengthened. One hypothesis explaining this enhancement of spontaneous entrainment is that the limb movements and eye movements are linked through a neuromuscular coupling or synergy. Another is that eye-tracking facilitates the pick up of important coordinating information. Experiment 1 investigated the first hypothesis by evaluating whether any rhythmic movement of the eyes would facilitate spontaneous entrainment. Experiments 2 and 3 (respectively) explored whether eye-tracking strengthens spontaneous entrainment by allowing the pickup of trajectory direction change information or allowing an increase in the amount of information to be picked-up. Results suggest that the eye-tracking enhancement of spontaneous entrainment is a consequence of increasing the amount of information available to be picked-up.     

RESPONSIBILITY TO PROTECT AND MILITARIZED HUMANITARIAN INTERVENTION: When and Why the Churches Failed to Discern Moral Hazard

This essay addresses moral hazards associated with the emerging doctrine of the Responsibility to Protect (R2P). It reviews the broad acceptance by the Vatican and the World Council of Churches of the doctrine between September 2003 and September 2008, and attempts to identify grounds for more adequate investigation of the moral issues arising. Three themes are pursued: how a changing political context is affecting notions of sovereignty; the authority that can approve or refuse the use of force; and plural foundations for human rights in a religiously and otherwise plural world such that the human rights protection does not become tyrannical.     

Muscle fatigue as an investigative tool in motor control: A review with new insights on internal models and posture–movement coordination

Muscle fatigue is a common phenomenon experienced in everyday life which affects both our force capacity and movement production. In this paper, we review works dealing with muscle fatigue and motor control and we attempt to demonstrate how the Central Nervous System deals with this particular state. We especially focus on how internal models – neural substrates which can estimate the current state as well as the future state of the body – face this internal perturbation. Moreover, we show that muscle fatigue is an interesting investigative tool in understanding the mechanisms involved in posture–movement coordination.     

Changes in Muscle Activity in Response to Assistive Force during Isometric Elbow Flexion

Abstract

This study investigated the muscle activity and force variability in response to perturbation of assistive force during isometric elbow flexion. Sixteen healthy right-handed young men (age: 22.0?±?1.1?years; height: 171.9?±?4.8?cm; weight 68.4?±?11.2?kg) were recruited and the muscle activity of biceps brachii and triceps brachii were assessed using surface electromyography. Workload force and assistive force applied on isometric elbow flexion significantly affected the changes in both biceps and triceps muscle activities. A higher assistive force was shown to result in reduced biceps muscle activity compared to the unassisted period. In contrast, the efficiency of the assistive force acting on the biceps decreased as the assistive force increased. In general, the force variability of the biceps muscle remained approximately the same at lower workload force conditions than that at higher workload force conditions. In conclusion, higher assistive force may not yield a higher performance efficiency in human-assistive force interaction.     

The meaning of service questionnaire and its association with psychological growth among Veterans

ABSTRACT

Few studies have investigated what soldiers find meaningful after being exposed to highly stressful events and what positive effects they might have in the aftermath. This study reports the psychometric properties of a newly developed questionnaire, Meaning of Service (MoS), and its application to the study of how strongly meaning-making processes are associated with psychological growth. One hundred eighty-four Norwegian Air Force Veterans who have participated in various missions abroad in different branches of the military completed the MoS questionnaire along with other scales reflecting psychological growth, hardiness, resilience, stress, and exposure, as well as personal and mission characteristics. The principal component analysis mainly identified three major meaning themes as expected from previous qualitative research (Confirmation of ability, Cohesion of peers, and Significance of effort). The hierarchical regression analysis showed that all three meaning themes and two coping strategies were associated with psychological growth, and that Confirmation of ability (coping and recognition of coping) seems particularly important to enhance Veterans’ prospects of psychological growth. Future research directions are proposed including suggestions for minor modifications of the questionnaire.     

武警某地区基层干部自我效能感研究

目的:探讨基层干部自我效能感的现状及其所呈现出的特点,为提升干部素质,提高管理水平提供参考。方法:采用标准问卷进行现场调查。结果:①基层干部的自我效能感在成长环境、是否独生、立功受奖等三个维度上没有显著差异;②基层干部的自我效能感在基层工作时间维度上有显著差异;③基层干部的自我效能感在成长环境和是否独生两个维度上的主效应和交互效应没有显著差异;④基层干部的自我效能感在基层工作时间和立功受奖两个维度上的交互效应没有显著差异。