Catherine Ayoun

Specific Grasp Characteristics of Children With Trisomy 21

Children with trisomy 21 display atypical manual skills that change to some extent during development. We examined grasp characteristics and their development in 35 children with trisomy 21, aged 4-18 years, who performed simple manual tasks (two manual tasks of the Movement Assessment Battery for Children, and grasping of five wooden blocks whose size was determined by their hand size). The age-matched comparison group included 35 typically developing children. Children with trisomy 21 were found to use fewer fingers than children in the comparison group in each task. They also used specific grasps and tended to extend fingers that were not involved in the grip. While some specific grasp characteristics of children with trisomy 21 decreased with age, other did not, and remained present throughout development. The perceptual-motor development of children with trisomy 21 should be analyzed in terms of atypical development rather than developmental delay.

Development of motor planning for dexterity tasks in trisomy 21

We examined the macroscopic aspects of motor planning in two manual dexterity tasks, comparing children, adolescents, and young adults with trisomy 21 (T21) with typically developing controls from a developmental perspective. We analyzed the order in which objects were picked up from a table during two manual tasks of the Movement Assessment Battery for Children (M-ABC). Participants with T21 were always slower than controls. Task completion times depended on the strategy used by participants to gather up the pegs or coins. A structured strategy, in which the participants picked the items up moving methodically along each row/column, contributed to rapid task completion by younger children and participants with T21. This study highlights the ability of children with T21 to select and maintain an efficient strategy that takes account of their motor difficulties. Developmental trajectories help to explain T21 functioning in these dexterity tasks.