The origin of human handedness and its role in pre-birth motor control

The vast majority of humans are right-handed, but how and when this bias emerges during human ontogenesis is still unclear. We propose an approach that explains postnatal handedness starting from 18 gestational weeks using a kinematic analysis of different fetal arm movements recorded during ultrasonography. Based on the hand dominance reported postnatally at age 9, the fetuses were classified as right-handed (86%) or left-handed, in line with population data. We revealed that both right-handed and left-handed fetuses were faster to reach to targets requiring greater precision (i.e., eye and mouth), with their dominant (vs. non-dominant) hand. By using either movement times or deceleration estimates, handedness can be inferred with a classification accuracy ranging from 89 to 100% from gestational week 18. The reliability of this inference hints to the yet unexplored potential of standard ultrasonography to advance our understanding of prenatal life

An evaluation of the Movement ABC-2 Test for use in Italy: A comparison of data from Italy and the UK

Background. The standardized test within the Movement Assessment Battery for Children-2nd edition (MABC-2) is used worldwide to assess motor problems in children. Ideally, any country using a test developed in another country should produce national norms to ensure that it functions effectively in the new context. Aim. The first objective of this study was to explore the differences in motor performance between Italian and British children. The second was to examine the structural validity of the test for the Italian sample. Method. A total of 718 Italian (IT) and 765 British (UK) children, aged 3–10 years, were individually tested on the age-appropriate items of the MABC-2 Test. Results. Developmental trends emerged on every task and differences between IT and UK children were obtained on 11 of 27 task comparisons. Interactions between age and country indicated that differences were not consistently in favor of one culture. Confirmatory factor analysis generally supported the proposed structure of the MABC-2 Test. Conclusion. Although the differences between the IT and the UK children were relatively few, those that did emerge emphasize the need for population specific norms and suggest that cultural diversity in motor experiences should be considered when evaluating motor abilities in children

Reaching in Children with and without Developmental Coordination Disorder (DCD) under normal and perturbed vision

The 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

Relation between Motor and Cognitive Skills in Italian Basketball Players Aged between 7 and 10 Years Old

There is evidence supporting a correlation between motor, attention and working memory in children. This present study focuses on children aged between 7 and 10 years, who have been playing basketball in the last two years. The aim of this study is to verify the correlation between cognitive and motor abilities and to understand the importance of this correlation in basketball practice. A total of 75 children who were 7.2–10.99 years old were assessed in terms of their attention, motor manual sequences and visuo-spatial working memory. A regression analysis was provided. In this sample, the motor abilities of children were found to be correlated with attention (denomination task, R2 = 0.07), visuo-spatial working memory (R2 = 0.06) and motor manual sequencing (aiming and catching task, R2 = 0.05; and manual dexterity task, R2 = 0.10). These correlations justify the suggestion to introduce deeper cognitive involvement during basketball training. The development of executive functions could have an important impact on basketball practice and the introduction of attention and memory tasks could help coaches to obtain optimal improvement in performance during the training sessions

Music Training Increases Phonological Awareness and Reading Skills in Developmental Dyslexia: A Randomized Control Trial.

There is some evidence for a role of music training in boosting phonological awareness, word segmentation, working memory, as well as reading abilities in children with typical development. Poor performance in tasks requiring temporal processing, rhythm perception and sensorimotor synchronization seems to be a crucial factor underlying dyslexia in children. Interestingly, children with dyslexia show deficits in temporal processing, both in language and in music. Within this framework, we test the hypothesis that music training, by improving temporal processing and rhythm abilities, improves phonological awareness and reading skills in children with dyslexia. The study is a prospective, multicenter, open randomized controlled trial, consisting of test, rehabilitation and re-test (ID NCT02316873). After rehabilitation, the music group (N = 24) performed better than the control group (N = 22) in tasks assessing rhythmic abilities, phonological awareness and reading skills. This is the first randomized control trial testing the effect of music training in enhancing phonological and reading abilities in children with dyslexia. The findings show that music training can modify reading and phonological abilities even when these skills are severely impaired. Through the enhancement of temporal processing and rhythmic skills, music might become an important tool in both remediation and early intervention programs.Trial Registration: ClinicalTrials.gov NCT0231687

The development of upper limb movements: from fetal to post-natal life.

BACKGROUND: The aim of this longitudinal study was to investigate how the kinematic organization of upper limb movements changes from fetal to post-natal life. By means of off-line kinematical techniques we compared the kinematics of hand-to-mouth and hand-to-eye movements, in the same individuals, during prenatal life and early postnatal life, as well as the kinematics of hand-to-mouth and reaching-toward-object movements in the later age periods. METHODOLOGY/PRINCIPAL FINDINGS: Movements recorded at the 14(th), 18(th) and 22(nd) week of gestation were compared with similar movements recorded in an ecological context at 1, 2, 3, 4, 8, and 12 months after birth. The results indicate a similar kinematic organization depending on movement type (i.e., eye, mouth) for the infants at one month and for the fetuses at 22 weeks of gestation. At two and three months such differential motor planning depending on target is lost and no statistical differences emerge. Hand to eye movements were no longer observed after the fourth month of life, therefore we compared kinematics for hand to mouth with hand to object movements. Results of these analyses revealed differences in the performance of hand to mouth and reaching to object movements in the length of the deceleration phase of the movement, depending on target. CONCLUSION/SIGNIFICANCE: Data are discussed in terms of how the passage from intrauterine to extra-uterine environments modifies motor planning. These results provide novel evidence of how different types of upper extremity movements, those directed towards one's own face and those directed to external objects, develop

D\ue9veloppement de l\u2019action planifi\ue9e chez le f\u153tus humain

\uc0 partir de quand un mouvement cesse-t-il d'\ueatre un r\ue9flexe pour acqu\ue9rir les caract\ue9ristiques de l'action volontaire ? L'interaction dynamique entre l'\ueatre humain et son environnement est-elle d\ue9j\ue0 pr\ue9sente avant la naissance ? L'\ue9tude des mouvements f'taux repr\ue9sente une occasion unique pour tenter de r\ue9pondre \ue0 ces questions en observant l'\ue9volution des mouvements des membres sup\ue9rieurs. Durant la gestation il y a des diff\ue9rences dans la fr\ue9quence des mouvements dirig\ue9s vers les diff\ue9rentes parties de la t\ueate, mais les mouvements de la main vers la bouche et les yeux semblent les plus fr\ue9quents. La pr\ue9sence de ces deux cat\ue9gories de mouvements \ue0 diff\ue9rents stades de la gestation permet d'\ue9tudier si une intentionnalit\ue9 dans le mouvement des membres sup\ue9rieurs appara\ueet \ue0 un certain moment de la p\ue9riode foetale. Cet objectif a \ue9t\ue9 suivi dans deux recherches. La premi\ue8re a pris en consid\ue9ration 8 grossesses monof'tales et la deuxi\ue8me 5 grossesses g\ue9mellaires. Dans la premi\ue8re recherche, les mouvements foetaux de la main ont \ue9t\ue9 enregistr\ue9s \ue0 la 14e, 18e et 22e semaine gestationnelle, alors que dans la deuxi\ue8me les mouvements n'ont pu \ueatre enregistr\ue9s qu'\ue0 la 14e et 18e semaine. L'enregistrement \ue9chographique pour chaque \ue2ge gestationnel a \ue9t\ue9 de 20 minutes. Il a \ue9t\ue9 analys\ue9 en utilisant un logiciel d\ue9velopp\ue9 sp\ue9cialement pour extraire, off-line, les param\ue8tres cin\ue9matiques : temps de d\ue9c\ue9l\ue9ration et temps de mouvement. Les r\ue9sultats sugg\ue8rent que les foetus, de grossesses simples ou g\ue9mellaires, peuvent ajuster le mouvement de la main en fonction de la cible \ue0 atteindre, sans doute en utilisant les diff\ue9rentes sensations de leurs organes sensoriels. Il semble donc que le f'tus \uab reconnaisse \ubb que la bouche est une cible moins d\ue9licate que ses yeux et que donc il peut s'en approcher plus rapidement que lors d'un mouvement vers l'oeil. En outre l'analyse temporelle des mouvements de la main vers le jumeau permet de v\ue9rifier que le contact vers le jumeau n'est pas accidentel et seulement d\ufb \ue0 la proximit\ue9 spatiale, mais volontairement dirig\ue9 vers lui. Ces donn\ue9es pr\ue9liminaires mettent en \ue9vidence la pr\ue9sence dans les mouvements des membres sup\ue9rieurs du f'tus d'une forme primitive d'action intentionnelle, avec un pattern cin\ue9matique qui varie en fonction de l'objectif de l'action

A comparison of the reach-to-grasp movement between children and adults: a kinematic study

In 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