Impact of Handedness Consistency on Bimanual and Unimanual Continuous Movements

Bimanual coordination is an essential human function requiring efficient interhemispheric communication to produce coordinated movements. Previous research suggests a “bimanual advantage” phenomenon, where completing synchronized bimanual tasks results in less variability than unimanual tasks. Additionally, of hand dominance has been shown to influence coordinated performance. The present study examined the bimanual advantage in individuals with consistent and inconsistent handedness. It was predicted that participants with consistent handedness would not display a bimanual advantage unlike those with inconsistent handedness. Fifty-six young adults completed a finger-tapping paradigm in five conditions: unimanual tapping with either left or right hand, in-phase bimanual tapping, and out-of phase bimanual tapping led by either left or right hand. Results were not consistent with the hypothesis that participants with consistent handedness displayed the “bimanual advantage”. However, the “bimanual advantage” was not evident for the inconsistent handers when the temporal consistency was measured with either the left or right hand only. Overall, the “bimanual advantage” may be dependent upon consistency of hand preference, as well as the direction of hand dominance.     

Topological assessment of gait synchronisation in overground walking groups

Walking is one of the fundamental forms of human gross motor activity in which spatiotemporal movement coordination can occur. While considerable body of evidence already exists on pedestrian movement coordination while walking in pairs, little is known about gait control while walking in more complex topological arrangements. To this end, this study provides some of the first evidence of spontaneous gait synchronisation while walking in a group. Nine subjects covered the total distance of 40 km at different speeds while assembled in a three-by-three formation. Two experimental protocols were applied in which the subjects were either not specifically asked to or specifically asked to synchronise their gait. To obtain results representative from the point of view of gait control, the movement coordination was quantified using the indirectly measured vertical component of ground reaction force, based on output from a network of wireless motion monitors. Bivariate phase difference analysis was conducted using wavelet transform, synchronisation strength measures derived from Shannon entropy, and circular statistics. A fundamental relationship describing the influence of the group walking speed on individuals’ pacing frequency was established, showing a positive correlation different from that previously reported for walking in solitude. A positive correlation was found between the average synchronisation strength within a group and group’s walking speed. The most persistent coordination patterns were identified for pedestrians walking front-to-back and side-by-side. Overall, the spontaneous gait synchronisation while walking in a group is relatively weak, well below the levels reported for walking in pairs.     

The control of amplitude and direction in a bimanual coordination task

Bimanual coordination requires task-specific control of the spatial and temporal characteristics of the movements of both hands. The present study focused on the spatial relationship between hand movements when their amplitude and direction were manipulated. In the experiment in question, participants were instructed to draw two lines simultaneously. These two lines were instructed to be drawn in mirror symmetric or perpendicular directions of each other while the length was instructed to be the same or different. The coordinative quality of amplitude control was compared when the task required symmetric and asymmetric bimanual spatial coordination patterns. Results showed that the amplitude accuracy decreased when different amplitudes and/or directions had to be generated simultaneously. The coordinative quality of direction was also compared when the task required symmetric and asymmetric bimanual spatial coordination patterns. Unlike amplitude, the direction accuracy was largely independent of coordination symmetry/asymmetry of direction or amplitude. The results suggest that the coordinative quality of amplitude control does not only interfere with amplitude asymmetry, but it also interferes with direction asymmetry. Moreover, in bimanual coordination amplitude control is more vulnerable to the influence of direction control demands than vice versa.     

Deployment trauma and seeking treatment for PTSD in US soldiers

Many service members in need of mental health treatment do not seek such treatment. This study investigated the frequency of Army soldiers’ exposure to specific types of deployment stressors and whether different event-types were associated with willingness to seek and actual receipt of treatment. Male soldiers who were married (n = 600) completed online surveys that assessed posttraumatic stress disorder (PTSD), willingness to seek treatment for PTSD, actual receipt of PTSD treatment, and the frequency of exposure to 4 types of potentially traumatizing warzone experiences: committing a moral injury, observing a moral injury, threats to life, and traumatic loss. Soldiers who reported greater exposure to moral injury experiences (committed or observed) were less likely to be willing to seek treatment, regardless of PTSD symptom severity. Although exposure to moral injury did not differentiate actual treatment receipt, soldiers who endorsed loss were more likely to have received treatment, regardless of PTSD symptom severity. These results suggest that the types of trauma experienced during deployment may be a factor in postdeployment treatment-seeking attitudes and behaviors.     

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.     

Challenges Marriage-Hunting People Face: Competition and Excessive Analysis1

In this paper, the reality of marriage hunting is examined through the narratives of marriage-hunting people. The results show that marriage hunting is based on the premise of a “competitive situation” and that people seeking a marriage partner require “analyzing” in order to win in this situation. However, the results indicate that marriage hunting becomes unsuccessful because, ironically, analyzing prevents people from behaving freely. Furthermore, the causes of their failure are attributed to them, thus giving rise to more analyzing. These findings suggest that the key to the future of marriage hunting is to free oneself from being governed by rules. The paper closes with a discussion of the importance of viewing marriage hunting as a relational effect.