Typical and atypical ( XXXX ) development of unimanual and bimanual grasp planning.

@entity1 @entity306
In the present study we tested 13 @entity1 with @entity306 ( @entity306 ) and 24 typically developing @entity1 (7-12 years old) in a unimanual and bimanual motor planning task. We focused on two research questions: (1) How does motor planning develop in @entity1 with and without @entity306 ? and (2) Is motor planning facilitated when the task is performed with both hands? @entity1 had to grasp one or two vertical oriented cylinder(s) and transport it/them to a platform that had different heights. As a measure of motor planning, we registered the height at which @entity1 grasped the cylinder. Here, anticipation of grasp height upon the height of the upcoming target(s) is reflective of proper forward motor planning as it leads to a comfortable posture at the end of the task. In the unimanual task the typically developing @entity1 showed a significant grasp height effect, which increased with age. In contrast, no grasp height effect, or age related changes therein were found for the @entity1 with @entity306 , suggesting a compromised development of motor planning in these @entity1 . Interestingly, when @entity1 had to transport one cylinder to a high shelf and one cylinder to a low shelf, the more affected hand of the @entity306 children clearly anticipated the grasp height to the upcoming target height. The less affected hand did not show such anticipation. Taken collectively, these findings suggest a delayed or compromised development of motor planning in @entity1 with @entity306 compared to typically developing @entity1 . At the same time, the facilitated motor planning of the more affected arm in the bimanual task offers a valuable entry point for intervention to improve motor planning in @entity306 .
