Direction of response in aiming to visual and proprioceptive targets in children with and without Developmental Coordination Disorder

Children with developmental coordination disorder (DCD) and controls matched on age, sex and verbal ability were tested on a positional aiming task in which they had to move one hand underneath a table top in order to match the position of a target on the top of the table. The target was speci®ed by vision, proprioception, or by vision plus proprioception. Analyses of error to the right and left of the target produced di€erent outcomes for di€erent conditions. When the children could only feel the target both children with DCD and controls made errors which showed bias outwards away from the midline. In the visual + proprioceptive target condition, the control children showed proprioceptive dominance of right/left position for both right and left hands. In contrast children with DCD showed visual dominance of position indicated by the left hand and proprioceptive dominance when position was indicated by the right hand, suggesting that positional information from the left hand is less reliable in these children and can be overridden by vision. Errors towards and away from the body were found chie ̄y with visual targets and not with proprioceptive ones. Children with DCD made larger errors than control children towards and away from the body with visual targets, but not with proprioceptive targets. The results suggest that detailed spatial analyses of error in aiming tasks produce information about target representation which is not available in more traditional error analyses. Ó 1998 Elsevier Science B.V. All rights reserved. Human Movement Science 17 (1998) 515±539 * Corresponding author. Tel.: +44 1524 593856; fax: +44 1524 593744; e-mail: m.smyth@lancas-