Temporal variability in continuous versus discontinuous drawin...

Children with Developmental Coordination Disorder (DCD) are reported to have high temporal variability in tasks requiring precise timing. The current study examined whether this timing deficit was due to the cerebellar 'explicit timing' process in the discontinuous, but not the continuous movement. Ten children with DCD and 31 typically developing children performed continuous, discontinuous circle and line drawing tasks. Results showed that both children with DCD and their age-matched controls had higher temporal variability in the discontinuous than that in the continuous movements. Individual comparisons between each child with DCD and the performance of typically developing children revealed that 2 out of 10 children with DCD showed limited timing deficit in both types of discontinuous drawing (lines and circles). Additionally, three different children with DCD had timing problems with only discontinuous line drawing. Thus, the possibility of a compromised cerebellar function may exist in a subgroup of children with DCD. This work raises a critical issue with respect to the functional heterogeneity of this population and emphasizes the importance of an individualized analysis in this movement disorder.