Repeated measure one way ANOVA was used to compare the mean difference of using a toy car for mobility, socialization and development before and after the intervention, and the follow-up. One way ANOVA was used to compare the mean difference of all developmental tests (mobility, socialization, motor, cognition) between two groups before and after the intervention and the end of follow-up phase. To analyze the learning curve, the results of socialization will be individually examined for each participant in two groups. The instant of the maximum training effect will be defined as the moment the top of the learning curve is reached. This top will be independently determined by two coders through visual examination of the absolute values. Subsequently, the data set will be split in children that have reached a maximum effect within the 9 weeks intervention period and those who have not. These two groups will then be compared with regard to demographic (age, gender) and clinical (manual ability classification system-MACS, gross motor function classification system-GMFCS) characteristics (using X2-test for dichotomous variables and Mann-Whitney U test/or t-test for the MACS and GMFCS depending on the normality of data).