The ability to modulate bilateral
finger tapping in time to different
frequencies of an auditory beat was studied. Twenty children, 7years of age, 10 with and 10 without
developmental coordination disorder (DCD), and 10 adults tapped their left index and right
middle fingers in an alternating pattern in time with an auditory signal for 15s (four trials each,
randomly, at 0.8, 1.6, 2.4, 3.2Hz per
finger). Dominant and non-dominant
finger data were collapsed since no differences emerged. All three groups were able to modulate their
finger frequency across trials to closely approximate the signal
frequency but children with DCD were unable to slow down to the lowest
frequency. Children with DCD were more variable in tap
accuracy (SD of relative phase) and between
finger coordination than typically developing children who were respectively more variable than the adults. Children with DCD were unable to consistently synchronize their
finger with the beat. Adults were tightly synchronized and often ahead of the beat while children without DCD tended to be behind the beat. Overall, these results indicated that children with DCD can only broadly match their
finger movements to an auditory signal with variability and poor synchronicity as key features of their auditory-fine-motor control. Individual inspection of the data revealed that five children with DCD had difficulty matching the slowest
frequencies and that these children also had higher variability and lower
percentile MABC scores from the movement assessment battery for children (MABC) than other children with DCD. Three children with DCD were more variable only at higher
frequencies and two performed like typically developing children.
