Clinical Bottom Line
“How should I apply this information?”
Children with developmental coordination disorder (DCD) are known to have poor upper limb coordination. Previous studies demonstrated that, compared with age-matched peers, children with DCD had slower reaction times (RTs) when manipulating stable objects, which was hypothetically due to difficulty using sensory input to plan a motor response. Children with DCD also exhibit slower and more variable movement time (MT), excessive peak force (PF), and difficulty maintaining steady force causing difficulty executing accurate movements.
In this study, children with DCD had slower RTs, MTs, and increased PF when manipulating moving objects. Children with DCD succeeded in intercepting an object in two-thirds of the trials compared with peers developing typically who succeeded in every trial. Interestingly, failed trials were associated with faulty motor strategies not slowed RTs. Children with DCD were able to perceive changing toy speed and altered their MT and PF responses in a manner similar to that of their peers. However, the accuracy of the adjusted motion was not improved. Therefore, interventions that focus on improving accuracy of upper limb movement strategies may be beneficial for children with DCD.
“What should I be mindful about in applying this information?”
This study suggests that children with DCD may have difficulty with open movement skills such as catching/striking a moving object. Peak force, RT, and MT findings were consistent with findings of previous studies. Although children with DCD could utilise visual cues to modify MT in this study, previous studies have indicated that visual cues could not be used to alter movement direction.
The fact that children with DCD could modify future movements based on previous trials differentiates their motor performance from that of children with cerebellar lesions who have difficulty adapting on the basis of prior trials. This gives hope that learning may result from interventions.
The relationship between these research laboratory findings and functional skills remains unknown. The Movement Assessment Battery for Children is widely utilized for children with DCD. Interestingly, no significant association was found between Movement Assessment Battery for Children score and RT, MT, and PF. Finally, limitations of this study include small sample size and limited age range, so results cannot be generalized to all children with DCD.
Tanya Grabinski, PT, MHS, PCS Kimberly Harbst, PT, PhD University of Wisconsin–La Crosse