Austin is nine years old and was recently hit by a car while riding his bike on the sidewalk. He broke his arm and leg and also hit his head very hard. When he came home from the hospital he looked just fine, but he needed a tremendous amount of help. Now back in school, there are changes in Austin that are hard to understand. It takes Austin longer to do things and he has trouble remembering. He cannot always find the words he wants to use. Dr. Carter’s math class is difficult for him now, but it was his strongest academic area before the accident. What developmental disability does he have and why?