Hi, welcome to the ehealth forum and I am glad to help you.
You seem concerned by the possibility of autism in your 4 year old son.
Autism includes a broad spectrum of symptoms. Therefore, a single, brief evaluation cannot predict a child's true abilities. Ideally, a team of different specialists will evaluate the child. They might evaluate:communication,language,motor skills,speech,success at school,thinking abilities
Because there is no biological test for autism, the diagnosis will often be based on very specific criteria from a book called the Diagnostic and Statistical Manual IV.
Autism can be associated with other disorders that affect the brain, such as:Fragile X syndrome,Mental retardation,Tuberous sclerosis
You must consult an appropriate medical facility where Autism kids are evaluated and treated as the same is not possible online.
Hope this helps. Take care.
Note: This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.