Children With Developmental Coordination Disorder

This study tested the effect of task-specific training of a perceptual ability for children with Developmental Coordination Disorder (DCD) compared to control children. A manual matching task (target location and pointing task) was used, which required the children to locate target pins either visually (seen target) or proprioceptively (felt target), while matching to the located target was always carried out without vision. Thirty-one children (11-12 years) were selected based on teacher statements regarding everyday motor skill performance, the DSM-IV criteria, and the Movement ABC test. Based on this, 10 children with obvious motor problems were placed in the DCD group (Trg-DCD), 9 children with no identified motor problems were placed in a training group (Trg-N), and 12 children also with no identified motor problems were placed in a control group. All the children were tested pre and post to training on a manual matching task. In the pretest, the children in the DCD group were significantly inferior to the control groups in the proprioceptive condition with both the preferred and nonpreferred hands. In the posttest, after the training periode was completed, the DCD subjects showed significant improvement in the proprioceptive condition for both preferred and nonpreferred hands. For the other groups, no significant training effects were observed across the training period. It is concluded that children in the DCD group may benefit from specific training of perceptual abilities, because they have motor control resources not exploited due to a lack of relevant experience.

The effects of background white noise on memory performance in inattentive school children

Background

Noise is typically conceived of as being detrimental for cognitive performance; however, a recent computational model based on the concepts of stochastic resonance and dopamine related internal noise postulates that a moderate amount of auditive noise benefit individuals in hypodopaminergic states. On the basis of this model we predicted that inattentive children would be enhanced by adding background white noise while attentive children's performance would deteriorate.

Methods

Fifty-one secondary school pupils carried out an episodic verbal free recall test in two noise conditions. In the high noise condition, verb-noun sentences were presented during auditory background noise (white noise, 78 dB), and in the low noise condition sentences were presented without noise.

Results

Exposure to background noise improved performance for inattentive children and worsened performance for attentive children and eliminated episodic memory differences between attentive and inattentive school children.

Conclusions

Consistent with the model, our data show that cognitive performance can be moderated by external background white noise stimulation in a non-clinical group of inattentive participants. This finding needs replicating in a larger sample using more noise levels but if replicated has great practical applications by offering a non-invasive way to improve school results in children with attentional problems.

Development of proprioceptive sensitivity

The development of proprioceptive sensitivity was studied in 140 children between the ages of 5.8 and 11.8 years using a so-called foot-hand task. Ten boys and ten girls were included in each age group. The task required the children to locate a target pin with the "big toe" (felt target) and match the located target position with the hand, without vision. There were four conditions: location of targets by the right big toe: matching located target position with the right hand (RfRh) and left hand (RfLh); and location of targets by the left big toe: matching located target position with the left hand (LfLh) and right hand (LfRh). The results showed a significant developmental trend in proprioceptive sensitivity, when the absolute error scores for boys and girls were combined, with most of the improvement occurring between the ages of 5.8 and 7.8 years. The most interesting and novel finding seems to be the significant two-way interaction between age and sex--the clearest differences manifesting themselves in the age group 9.9 years. Separate within-sex group analyses showed the trend to be determined by the results for the girls, the trend being absent in the results for the boys. Furthermore only the boys showed a significant difference between the intra- and inter-hemispheric conditions. We propose that these differences may only manifest themselves in particular tasks, i.e. there may be a sex-task interaction. The implications of this proposal for theoretical interpretations of the phenomenon of inter-hemispheric processing as well as possible sources of the task differences are briefly discussed.