Subjects will be provided with a one-week supply of VyvanseTM 30mg/day. Subjects will begin treatment the morning of the baseline visit and continue on the same dose for the next week. The first dose of medication will be administered on site and subsequent dosing will be given to the subject's parent(s)/legally authorized representative who will be required to administer study drug to the subject upon awakening. During the visit subjects will perform the Attention Task while the NIRS is recording and they will also be given the Gray's Oral Reading Test before the medication is administered. After the medication is administered the subject will stay on site until the second NIRS measurement can be taken a second time. They will be provided food and activities during the waiting period.