Evaluation of Motor Performance of Brazilian Children with Developmental Coordination Disorder through the 'Movement Assessment Battery for Children' and the 'Körperkoordinationstest Für Kinder'

Background: Children with Developmental Coordination Disorder (DCD) have deficits in fundamental motor skills (e.g. catching, flinging, jumping and running) and complex motor skills (related to the contexts of sports, games and leisure) when compared to their typically developing peers. These deficits may compromise motor performance, impacting the daily life functionality of these children. In addition, different levels of motor performance can be observed within this motor disorder because DCD is a complex and multifactorial condition. As example, moderate and severe DCD are common terminologies used in the field, to classify children <16° percentile and <5° percentile in motor performance assessment related to DCD, respectively. Thus, evaluating the motor performance of these children with specific instruments is essential for the identification of impairment and provision of effective intervention. Yet, given the specificities across instruments available to assess motor performance along with the complex features surrounding children with DCD, differences among those instruments should compose the purpose of investigations in the motor skills field during childhood. Purpose: To compare the motor performance of Brazilian children with severe DCD (s-DCD) and moderate DCD (m-DCD) using two motor assessment instruments: the Movement Assessment Battery for Children -- Second Edition (MABC-2) and the "Körperkoordinationstest Für Kinder" (KTK). A total of 123 children, 66 with s-DCD and 57 with m-DCD, with a mean age of 8.7 (± 0.85) years were evaluated in this cross-sectional study. Results: No significant difference was found between the mean percentiles of the general motor performance of the children in the MABC-2 and KTK tests (p = 0.06). We observed significant correlations between the MABC-2 and KTK tests, ranging from 0.17 (very weak) to 0.47 (moderate). The strongest correlation was observed between the MABC-2 Balance component score and the KTK MQ Walking backwards (r = 0.47). The majority of children with s-DCD were classified as impaired, and the minority were classified as normal in the KTK test. Yet, the majority of those with m-DCD were classified as normal in the KTK test. An independent t-test showed a significant difference for most of the comparisons performed between the s-DCD and m-DCD groups. Conclusion: As expected, children with s-DCD scored lower in all MABC-2 components as well as in the quotients of KTK. Thus, the analysis of motor performance by the MABC-2 and KTK indicated that Brazilian children with s-DCD presented with more difficulties in motor performance than children with m-DCD, demonstrating the need for dividing children into these groups when studying them. Additionally, the use of two motor assessment instruments is recommended to better understand and support motor skills among children with DCD.