1,720,965 research outputs found
Reaching in Children with and without Developmental Coordination Disorder (DCD) under normal and perturbed vision
No full textThe aim of this study is to describe the reaching action of children with developmental coordination disorder (DCD) and to investigate whether their use of visual feedback during the time course of this action differs from that of normally developing children. Fifty-two children subdivided into 2 age bands (7-8 and 9-10 years) within 2 groups (with and without DCD) participated in this experiment. They were asked to reach for a target positioned either ipsilaterally or contralaterally to the reaching hand in 2 visual conditions: a condition where vision was unrestrained (normal vision) and a condition where they wore glasses with prismatic lenses (perturbed vision). An analysis of the experimental data indicates that the trajectories followed by the DCD group were longer and more curved than those of the control group. Further, the deceleration times were longer for the DCD group than for the normally developing children. The introduction of the prismatic lenses supports the idea that the use of visual feedback by children with DCD may be different from that in children without DCD
A comparison of the reach-to-grasp movement between children and adults: a kinematic study
No full textIn this study, the reach-to-grasp movement of 5-year-old children was compared to that of adults. Participants were required to reach out and grasp objects, with and without on-line visual feedback. Object size and distance were covaried in a within-subjects design and it was found that for both groups, grip formation and reach kinematics were affected by the manipulation of either variable. Although there are a large number of similarities, a few differences between the two groups emerge. For the reaching component, the children revealed a longer movement duration and deceleration time and a lower maximum height of wrist trajectory than in adults. For the grasp component, the children, in both the vision and no-vision condition, show a maximal finger aperture larger than the adults. Further, the children of this study were able to scale their grip aperture according to object size when visual feedback during the movement was lacking. These findings suggest that children adopt different strategies than adults when planning a reach-to-grasp movement on the basis of object size, distance, and the predictability of visual feedback. The results are discussed in terms of the neural mechanisms underlying hand action and how these mechanisms may not be fully developed by the age of 5
Evidence of early development of action planning in the human foetus: a kinematic study
Full text linkThe aim of the present study was to investigate whether foetal hand movements are planned and how they are executed. We performed a kinematic analysis of hand movements directed towards the mouth and the eyes in the foetuses of eight women with normally evolving pregnancies. At 14, 18 and 22 weeks of gestation, eight foetuses underwent a 20-min four-dimensional-ultrasound session. The video recordings for these movements were then imported into in-house software developed to perform kinematic analysis. We found that spatial and temporal characteristics of foetal movements are by no means uncoordinated or unpatterned. By 22 weeks of gestation the movements seem to show the recognizable form of intentional actions, with kinematic patterns that depend on the goal of the action, suggesting a surprisingly advanced level of motor planning
What can reaching movements in typically developing children tell us about reaching in DCD?
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Hand movements of monochorial and bichorial twins: a kinematic study for early evidence of action planning
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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