Sensorimotor functioning in developmental coordination disorder, a kinematic and psychometric analysis

Abstract

The purpose of the present research was twofold: 1) to investigate whether deficits in sensorimotor mechanisms in DCD could be characterized using kinematic and psychometric analyses, and 2) to determine whether subtypes of sensory and/or motor deficits could be identified within a group of children identified with DCD. Participants included 40 children between the ages of 7-9 and 10-12 years, 20 who were clinic referred and met the diagnostic criteria for DCD and 20 age-matched controls without motor difficulties. Participants performed a manual aiming task with and without visual feedback of the moving hand to targets of varying complexity. Kinematic analyses of aiming movements revealed that the effects of sensory feedback on movements in DCD are dependent on several factors including age, feedback availability, and task complexity. With increases in task complexity, children with DCD demonstrated difficulty processing visual and non-visual feedback leading to an increased reliance on feedback control and/or decreased spatial accuracy and a higher frequency of kinematic abnormalities. Children with DCD were also found to perform significantly below average on standardized measures of sensory and motor functioning. Individual analyses of kinematic profiles within the DCD group revealed that both age groups of children with DCD demonstrated a large degree of variation in kinematic performance patterns in the absence of visual feedback. These patterns of performance were not related to any of the standardized measures indicating that distinct subtypes of sensory or motor deficits in the DCD population are unlikely. The results suggest, rather, that there are subgroups of children with DCD who demonstrate different control strategies to cope with more generalized deficits in sensorimotor functioning. The neural substrates implicated in these findings are discussed along with approaches to intervention and directions for future research.