Auditory-motor coupling of bilateral finger tapping in children with and without DCD compared to adults.

The ability to modulate bilateral finger tapping in time to different frequencies of an auditory beat was studied. Twenty children, 7 years 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, 3.2 Hz 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.

Perception-action coupling in children with and without DCD: Frequency locking between task-relevant auditory signals and motor responses in a dual-motor task.

BACKGROUND: The current research examines the relationship between perceptual and motor processes, known as perception-action or sensorimotor coupling, and the potential differences in perception-action coupling among children with and without Developmental Coordination Disorder (DCD) and adults in a gross-motor co-ordination task (clapping while marching) when a task-relevant driving sensory signal is present. METHODS: Ten children with DCD (7.32 + 0.23 years), eight typically developing (TD) children who were age-, gender- and racially/ethnically matched (6.91 + 0.24 years) and 10 college-aged adults were participants in this study. Participants clapped and marched to an auditory beat at four different frequencies: 0.8, 1.2,1.6 and 2.0 Hz. The relative timing measures of mean relative phase (MRP) and variability of relative phase (VRP) were calculated and compared using 3 (group) x 4 (frequency) x 2 (limb) anovas. Qualitatively, participants were assessed for the presence of absolute coupling (100% + 15% MRP). RESULTS: Statistically significant differences in MRP occurred for coupling, frequency and group, and post hoc analysis indicated that the adult group differed from both the DCD and TD groups, who did not differ from each other. In VRP, there were significant main effects for coupling and group, and a significant interaction between group and frequency, with post hoc analysis indicating the DCD group to be different from the TD and adult groups. Qualitatively, both the adult and TD groups increased in the number of participants who adopt absolute coupling as frequency increases. In contrast, the DCD participants adopt this absolute coupling far less frequently overall; in fact, the number of participants adopting this pattern decreases as frequency increases. CONCLUSIONS: These results indicate that children with DCD have difficulties with both the co-ordination and the control of their perception-action coupling for this particular task.