There are lots of diagnostic tests, if you have concerns. One thing you should realize before going to a medical doctor is they love telling people what they think is wrong with them. They also like telling people that certain things cannot be healed.
I would recommend feeding your child an excellent diet with almost no processed food, junk food, or sugar of any kind. All developmental problems have some foundation in nutrition. I would recommend looking into Nutritional Balancing in order to become more educated on some of the nutritional causes of developmental issues. Doctors like to give rather toxic and ineffective "medicines" that treat the symptoms instead of the root causes.