In 2013, a systematic review of interventions for children with cerebral palsy (Novak et al, 2013) concluded that constraint-induced movement therapy (CIMT) produces the largest magnitude effects of any non-surgical treatment. Similarly, the first major handbook summarizing the results from more than 50 studies on CIMT conducted worldwide (Ramey, Coker-Bolt, & DeLuca, 2013) provides additional clinical and scientific support for the conclusion that CIMT can produce significant benefits. There are a number of important unresolved issues. One concerns the need for empirical evidence that CIMT is efficacious for infants and toddlers, since there has been no randomized controlled trial (RCT) focused on this age range. Another issue under debate is whether there are different effects related to the type of constraint used during the therapy. The constraint is placed on the child's "stronger" or non-hemiparetic upper extremity while the therapy focuses on improving the child's skills in using the impaired or hemiparetic upper extremity. Two widely used forms of constraint are: 1) a full-arm cast that the child wears continuously throughout a multi-week period when the child receives daily therapy and 2) a part-arm splint that the child wears only during the time of day when he or she receives therapy. Finally, another important topic that has not been studied is whether CIMT is a stressful form of therapy, because it is high-intensity (i.e., much higher dosage than the usual and customary sessions in other forms of occupational and physical therapy), involves constraining the child's non-involved or less involved upper extremity, and takes place in the child's home and often asks parents to help with practice sessions during non-therapy hours. If CIMT does produce elevated stress for the child, the parents, or both, is this stress short-term (i.e., just at the start of therapy) or does this continues over the entire period of therapy? Further, does the type of constraint used produce different levels of stress, either at first or throughout the course of therapy?