Three fundamental goals of early rehabilitation for children with DD are: optimizing body function within each child's prognostic potential, preventing the development of secondary conditions that impact life-long health, and promoting children's participation in their lives. Knowledge of these developmental patterns of FPLA may be helpful in understanding, anticipating, and managing the problems of these patients. The investigators hypothesize that the course of developmental patterns in Function and Participation in Life Activities (FPLA) of patients with DD evolves with their age. The levels of functional recovery included developmental function, activity, participation, and quality of life (QOL). The aim of this study is to investigate the longitudinal outcomes in patients with DD evaluated by developmental function, activity, participation, and QOL. Additionally, the predictors in the initial stage in determining the final developmental patterns in FPLA of these children will be identified.