Biomedical subjects

J Fagard

Publications and source records attributed to J Fagard.

4 recordsLinked to original sources

PubMed2001

Changes in interhemispheric transfer rate and the development of bimanual coordination during childhood.

In this study, we investigated the effect of the development of interhemispheric communication on age-related change in bimanual coordination. Interhemispheric communication was assessed by comparing the latency of a manual response to a visual stimulus when the hemisphere perceiving the stimulus and the hemisphere controlling the manual response were the same (uncrossed condition) to the latency when they were different (crossed condition). In the first experiment (5- to 10-year-old children) we used a two-choice response-time task, and in the second experiment (3- to 7-year-old children) we used a simple response-time task. In both studies, bimanual coordination was tested on a line-drawing task, and we compared performance on mirror and parallel movements. The crossed-uncrossed difference decreased with age in both experiments. When estimated on the simple response-time task, the crossed-uncrossed difference was related to the difference in performance between mirror and parallel movements on the bimanual task. Thus, improved interhemispheric communication contributes to progress in bimanual coordination, especially that which requires resisting the attraction of mirror movements in order to rotate both hands with parallel movements.

Age Factors↗

PubMed1997

Age Changes in Interlimb Coupling and the Development of Bimanual Coordination.

Changes in interlimb coupling, and their role in the development of bimanual coordination, were studied longitudinally in 6- to 12-month-old infants (N = 6). Infants were observed while they were reaching for simple objects of 2 different sizes. Their use of a uni- versus bimanual strategy for reaching as well as the coupling of their bimanual movements were compared; progress in bimanual coordination of complementary movements was evaluated on 3 different bimanual tasks. The bimanual tasks involved an asymmetrical cooperation between the 2 hands. Although spatiotemporal coupling of bimanual reaching movements did not decrease during the age period studied, infants around 7 months of age used their 2 hands infrequently for reaching. Occurrences of bimanual reaching were particularly low at the session preceding the first bimanual success at a bimanual task. This suggests that the temporal coincidence between greater independence of the 2 hands and progress in bimanual coordination of complementary movements acts in 2 directions: Infants may be more at ease when using their 2 hands in differentiated patterns as the hands move less in synchrony, but, in turn, they may be less likely to move their hands in synchrony as they anticipate mirror manipulations of the object less. The frequency of bimanual reaching increased toward the end of the 1st year. This might have been caused by an increase in the repertoire of bimanual asymmetrical object manipulations and by the fact that the development of bimanual coordination allows infants to manipulate objects with complementary movements even after a bimanual approach toward the object.

bimanual coordination↗

PubMed1987

Bimanual stereotypes: bimanual coordination in children as a function of movements and relative velocity.

Five-, 7-, and 9-year-old children were trained and tested in a bimanual coordination task that required them to rotate two cranks (either at the same or at different velocities) using mirror (inwards or outwards) or parallel movements (clockwise or counterclockwise). The task consisted of tracing two lines of different slants, by turning the two cranks either at the same velocity (to draw the 45 degrees slanted line) or at different velocities (to draw the 22 degrees line). The same-velocity condition resulted in significantly better performance than the different-velocities condition with the age x angle interaction: the performance in the different-velocities condition improved considerably at 9 years of age. Mirror movement induced faster and more accurate performance relative to parallel movements in the same-velocity condition but not in the different-velocities condition. This difference was much greater in 5- and 7-year-olds than in 9-year-olds. The results are interpreted as reflecting a decreasing influence of motor constraints on bimanual coordination.

Journal Article↗

PubMed1985

Early stages in the acquisition of a bimanual motor skill.

Children and adults were trained and tested on a coordinated bimanual task that required them to rotate both hands either at the same or at different angular velocities in order to move the pen of an X-Y recorder along three angles of slant (45, 67 and 22 degrees), and to rotate both hands in the same clockwise direction rather than as mirror image movements. Initially both groups exhibited a tendency to rotate both hands at the same angular velocity even when the task required differential motor output from the two hands. With visual feedback, the tendency toward synchronization, such that both hands moved at the same angular velocity, was asymmetrically distributed, but under blindfolded conditions such asymmetries disappeared. Accuracy of performance increased with practice; and visual feedback enhanced accuracy of performance. The findings suggest that during early stages in the acquisition of a bimanual skill, unintended bilateral coactivation occurs at multiple levels of motor organization; mirror associated movements are only one simple subset of unintentional intermanual synergies.

Adult↗