Brain Training in Children With/At-risk for Attention-Deficit/Hyperactivity Disorder and Executive Function Impairment

* Investigators will talk to you by telephone to determine if your child might be eligible for the study. * Children complete two baseline testing sessions to evaluate executive function (EF) and related skills * Parents complete a packet of information, including questionnaires about the child's behavior, EF, and functional skills. * After completion of the baseline testing, we will inform you of eligibility for the "Brain Training" phase. * During "Brain Training" children play online computer games for 25-30 minutes/day (can range from 15-45 minutes/day depending on your child's attention, training version received, number and length of breaks needed), 5 days a week, for 5-7 weeks to complete a total of 25 sessions. * Children return for 3 more time points, immediately after the completion of "Brain Training" (1 session), and also at 3 months (1 session) and 6 months (2 sessions) after completion of "Brain Training."