Impaired visuo-motor sequence learning in Developmental Coordination Disorder.

The defining feature of Developmental Coordination Disorder (DCD) is the marked impairment in the development of motor coordination (DSM-IV-TR, American Psychiatric Association, 2000). In the current study, we focused on one core aspect of motor coordination: learning to correctly sequence movements. We investigated the procedural, visuo-motor sequence learning abilities of 18 children with DCD and 20 matched typically developing (TD) children, by means of the serial reaction time (SRT) task. Reaction time measurements yielded two important findings. Overall, DCD children demonstrated general learning of visuo-motor task demands comparable to that of TD children but failed to learn the visuo-motor sequence. Interestingly, a sequence recall test, administered after the SRT task, indicated some awareness of the repeating sequence pattern. This suggests that the sequence learning problems of DCD children might be located at the stage of motor planning rather than sequence acquisition.