In adult humans, vision plays a dominant role in determining both the perceived location of the arms when stationary, and in controlling reaching (Holmes et al., 2004). It has been argued that vision becomes more important than proprioception in localization as a function of the increased visual experience typically obtained during childhood. We report data assessing the development of visual dominance in the control of reaching in children diagnosed with developmental coordination disorder (DCD; n=10) in comparison to age and IQ-matched typically developing group (45 children aged 6-12 years) and adults (n=15). Participants completed Holmes et al.’s (2004) mirror reaching task. In this task, participants viewed their left arm on both sides of their midline (by virtue of a mirror placed at the midline facing the left arm, and obscuring the right arm) and were asked to reach with their right (hidden) hand for a target placed 25cm in front of that hand. Reach accuracy was measured when proprioceptive and visual cues to the location of the right hand were placed in varying degrees of intersensory conflict (by moving the hidden hand in the azimuthal plane with respect to the mirror image of the left hand) and also when no visual information concerning the location of the hand was made available (by covering the mirror). Results indicate that all groups showed comparable visual capture effects (as demonstrated by a greater reliance on visual cues in the mirror even when these were misleading). However, the DCD group was more impaired at reaching accurately in the absence of visual information about their hand (i.e. when the mirror was obscured). We will discuss the implications of these findings regarding the development of multisensory representations of the body in typically developing individuals and individuals with DCD.

Holmes, N.P., Crozier, G. & Spence, C. (2004). When mirrors lie: “Visual capture� of arm position impairs reaching performance. Cognitive, Affective, & Behavioral Neuroscience, 4, 193-200.