<qa>  What is the main reason for CI therapy?CI therapy was derived from basic research with animal subjects and human volunteers. Randomized, controlled studies indicate that it can substantially reduce the motor deficit of patients with mild to moderate chronic strokes and can increase their independence over a period of years. CI therapy involves motor restriction of the less affected upper extremity for a period of 2 to 3 weeks while concurrently training the more affected upper limb. This gives rise to massed or concentrated repetitive use of the more affected extremity. CI therapy leads to a large increase in use-dependent cortical reorganization involving the recruitment of other regions of the brain in the innervation of the more affected extremity movement. 