The group randomized to the Working Memory intervention will receive Cogmed computerized training of executive function and attention skills. The standard Cogmed RM will be used for this trial arm. This is a child-friendly web-based software program. The investigators will use a version of the program that contains 12 different neurocognitive tasks. Tasks become more difficult as a function of performance on a session-by-session basis. Each training session lasts 35-40 minutes, with one session to be completed per day 5 days each week for 5 weeks, for a total of 25 sessions. The program yields individual session-by-session and task-by- task training results, including the adolescents' responses, time spent on each task, and evolution curves.

Adolescents randomly assigned to the control group will receive the standard of care recommended for patients with critical CHD. This includes cardiac surveillance and neurodevelopmental counseling and screening at our Cardiac Neurodevelopmental Program if needed. Once enrolled in our study, an adolescent in the control group will not receive Cogmed intervention or any other cognitive intervention that targets executive functions or ADHD symptoms until after the 3-month follow-up neurodevelopmental evaluation is performed, i.e., 5-6 months after initial enrollment. Like adolescents assigned to the intervention group, controls can continue on treatments that are already in place for other neurodevelopmental disabilities (e.g., speech therapy, occupational services).

Cogmed Working Memory Program will be used as a computerized home-based intervention. Families will receive a link for downloading a web-based software program. The program will be installed on a computer at a family's home by a research assistant. Parents and adolescents will be actively involved, and during the installation session, adolescents will complete several practice trials. The 25 sessions will be completed individually by the adolescent with parental supervision. For the first 5 sessions, the participant trains on the same set of games; on the 6th session and every 5th session thereafter, a new task is introduced and replaces one of the initial tasks. At the end of each session, the adolescent can play an age-appropriate computerized game as a reward. After each session, results are uploaded by parents to a secure website, to keep track of the participant's progress. Families will be contacted weekly to check program function and discuss concerns.

This standardized measure assesses the ability to process information across a series of modalities (visual-spatial and verbal), to hold this information in a short-term buffer, and to actively manipulate it mentally. It is considered an excellent composite indicator of adolescents' executive function skills, as it requires the simultaneous implementation of control of attention and working memory abilities on tasks of increasing complexity. Mean scores are automatically computed and are compared to a standardization sample of US adolescents of the same age. They are normally distributed (mean=100, SD=15).