Children with impaired motor coordination (or developmental coordination disorder) have difficulty representing internally the visuospatial coordinates of intended movements. We have proposed that this deficit reflects impairment in the generation of forward models of the efference copy of intended movements-the efference-copy-deficit hypothesis. In this study, we challenged this hypothesis by examining the efficacy of an imagery intervention designed specifically to train the forward modeling of purposive actions. A pre-post design was adopted. Fifty-four children referred with motor coordination problems were assigned randomly to one of three groups: imagery training, traditional perceptual-motor training, and wait-list control. The imagery protocol-delivered by an interactive CD-ROM-was shown to be equally effective to perceptual-motor training in facilitating the development of motor skill in the referred children. These results support the efference-copy-deficit hypothesis in explaining the cause of motor clumsiness in most children. Directions for future intervention studies and remediation in the field of developmental clumsiness are discussed.
Department of Psychology and Disability Studies, RMIT University, Melbourne, Victoria, Australia. firstname.lastname@example.org