Testing predictive control of movement in children with developmental coordination disorder using converging operations.

Recent systematic reviews (Wilson et al., 2013, Dev. Med. Child Neurol., 55, 217; Adams et al., 2014, Neurosci. Biobehav. Rev., 47C, 225) suggest that a common underlying problem in developmental coordination disorder (DCD) is the internal modelling deficit. The study presented here is the first to test this hypothesis using a within-subject design, assessing motor imagery, action planning, and rapid online control (ROC) in a sample of children screened rigorously for DCD. Participants were 66 children; 33 children (26 boys and seven girls) aged 6-11 years in the DCD group and 33 controls (gender and age matched). Motor imagery was assessed with the hand rotation task (HRT), action planning with an end-state comfort effect test, and ROC with the double-step pointing task. Results showed that children with DCD were slower and less accurate than controls in the HRT. Reduced forward planning for comfortable end-state was also shown in DCD. Finally, no group differences were found on the ROC task. Collectively, children with DCD manifest deficits in the internal modelling of movements, but this varies under different task constraints, particularly those related to movement complexity.