 Investigators will use tDCS to apply a low electrical current to the participants scalp in the area of the brain associated with fluent and flexible thinking. The current may make that area of the brain work better for a short period of time. During this time, the participant will play computer games designed to train the brain to work more fluently flexibly. Researchers at St. Jude Childrens Research Hospital want to see if pairing the electrical stimulation with the brain games at home is a feasible method to improve cognitive abilities in long-term survivors of childhood ALL. 