Abstract: This review included 15 studies (eight RCTs and seven quasi-RCTs). Study characteristics The trials included 649 participants of both sexes, ranging in age from five to 12 years. The participants were from Australia, Canada, China, Sweden, Taiwan, and the UK. Trials were conducted in hospital settings; at a university-based clinic, laboratory, or centre; in community centres; at home or school, or both at home and school. The durations of task-oriented interventions were mostly short term (less than six months), with the total number of sessions ranging from five to 50. The length of each session ranged from 30 to 90 minutes, and the frequencies ranged from once to seven times per week. We judged the risk of bias as moderate to high across the studies. Some elements were impossible to achieve (such as blinding of administering personnel or participants). Key results: primary outcomes A meta-analysis of two RCTs and four quasi-RCTs found in favour of task-oriented interventions for improved motor performance compared to no intervention (mean difference (MD) -3.63, 95% confidence interval (CI) -5.88 to -1.39; P = 0.002; I2 = 43%; 6 trials, 169 children; very low-quality evidence). A meta-analysis of two RCTs found no effect of task-oriented interventions for improved motor performance compared to no intervention (MD -2.34, 95% CI -7.50 to 2.83; P = 0.38; I2 = 42%; 2 trials, 51 children; low-quality evidence). Two studies reported no adverse effects or events. Through personal correspondence, the authors of nine studies indicated that no injuries had occurred. Key results: secondary outcomes Due to the limited number of studies with complete and consistent data, we were unable to perform any meta-analyses on our secondary measures or any subgroup analysis on age, sex, severity of DCD, and intervention intensity. We have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect. The conclusions drawn from previous reviews, which unanimously reported beneficial effects of intervention, are inconsistent with our conclusions. This review highlights the need for carefully designed and executed RCTs to investigate the effect of interventions for children with DCD.

Plain-language summary: We systematically searched for studies that examined the effect of task-oriented interventions for children with DCD. We found 15 appropriate studies involving 649 children from five to 12 years of age with a diagnosis of DCD. The participants were from Australia, Canada, China, Sweden, Taiwan, and the UK. Trials were conducted in hospital settings; at a university-based clinic, laboratory, or centre; in community centres; at home or school, or both at home and school. Most trials were small and of poor quality. The duration of the intervention was often short (i.e. less than six months). We were only able to combine the results from six studies in a meta-analysis, a statistical method to summarise the results from several independent studies. Together these studies suggest that task-oriented interventions have a moderately positive effect on movement problems. However, the finding from the two strongest studies alone indicated that task-oriented interventions do not improve movement problems. We were unable to use the remaining nine included studies in a meta-analysis because of insufficient data, or because the interventions used in the control groups (without a task-oriented intervention) were too different to combine. As a result, we were unable to perform any meta-analyses on many of our intended outcome measures or look at the effects of age, sex, severity of DCD, or how much intervention was received. Two studies reported no side effects. Through email correspondence, the authors of nine studies indicated that no injuries had occurred. The quality of the evidence was generally low, meaning we are very uncertain about the findings of this review. At the moment, task-oriented interventions may be useful for children with DCD in improving their performance on movement tests. We cannot be sure about benefits in other areas. Higher-quality research is needed to investigate and establish the effect of task-oriented intervention for children with DCD.