The effects of a concurrent cognitive task on the postural control of young children with and without developmental coordination disorder Yocheved Laufer a, * , Tal Ashkenazi a,b , Naomi Josman c a Physical Therapy Department, Faculty of Social Welfare and Health Studies, University of Haifa, Israel b Clalit Health Services, Child Development Center, Carmiel, Israel c Occupational Therapy Department, Faculty of Social Welfare and Health Studies, University of Haifa, Israel Received 7 September 2006; received in revised form 6 January 2007; accepted 23 April 2007 Abstract The purpose of this study was to examine how dual-task performance affects the center of pressure (COP) sway characteristics and cognitive performance of children with developmental coordination disorder (DCD). Twenty-six children with DCD (mean age—5.1  0.59 years) and 20 typically developing children (mean age—5.0  0.57 years) participated in the study. The postural task consisted of standing quietly either on a firm or a compliant surface. The cognitive task involved naming simple objects appearing consecutively on a computer screen. Five tests were presented in random order, with the cognitive and the postural tasks tested either separately or concurrently. Mistakes in naming the objects were recorded, as were COP sway characteristics measured with a force-plate. Children with DCD demonstrated higher COP path-length velocity (PLV), and COP amplitude variability, as well as more mistakes in naming the objects in all stance conditions. A concurrent cognitive task increased all sway measures in both groups, with the effect on PLV greater in children with DCD. Cognitive performance was affected by dual tasking only in the control group. Young children with DCD demonstrated greater postural control activity than did the children in the control group during quiet stance, whether performed as a single or a dual task. This difference is accentuated during dual tasking when the children with DCD seem to prioritize the cognitive task. # 2007 Elsevier B.V. All rights reserved. Keywords: Developmental coordination disorder; Dual tasking; Postural control 1. Introduction Developmental coordination disorder (DCD) refers to a disorder, not explainable by a medical condition, which is marked by impairment in the development of motor coordination. This impairment interferes significantly with daily motor activities and/or academic achievements [1]. Problems in the processing of visual, proprioceptive, or tactile information [2,3] and problems in visual-motor integration [4,5], are often considered to be the underlying cause of these difficulties which are identified in 5–9% of school age children [1]. Postural control, defined as the regulation of body position in space for the purposes of stability and orientation [6], is essential for the development of motor skills. It entails perceptual motor integration, and thus may be impaired in children with DCD. However, research relating to the postural control of children with DCD, as recently reviewed by Geuze, is rather limited [7]. Studies indicate that children with DCD utilize increased leg and trunk muscular activity in order to maintain balance [8–10]. Children with DCD have also been shown to have more difficulty in maintaining single-leg stance [11], and increased COP movement [12,13]. This is particularly the case in the more challenging stance conditions, such as during stance on one leg with eyes closed [8], during unexpected perturbations [8], or within a moving visual world [14]. www.elsevier.com/locate/gaitpost Gait & Posture 27 (2008) 347–351 Abbreviations: COP, center of pressure; DCD, developmental coordi- nation disorder; M-ABC, movement assessment battery for children; PLV, path length velocity; ML-SD, amplitude variability the medio-lateral direc- tion; AP-SD, amplitude variability the anterior-posterior direction; ANOVA, analysis of variance * Corresponding author. Tel.: +972 828 8090; fax: +972 4 828 8140. E-mail address: yocheved@research.haifa.ac.il (Y. Laufer). 0966-6362/$ – see front matter # 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.gaitpost.2007.04.013