possible autism

I have a son who is 17mos old. Since he was 4 mos he started having seizures,and at 5 mos started regressing. He has been involved in early intervention since 6mos old and is slowly making progress. He still doesn't "talk" no mama,dada, or anything like that. He is using some sign language though but only like more,help,stop. He is also very aggressive. Not only to others but to hisself aswell. In January he saw his neuro. and he told me he thinks he is Autistic. I don't think he is due to the fact some days he is cuddly, and somewhat social. Most days he doesnt make eye contact and refuses to be touched. His OT told me she thought he might have Sensory Integration Dysfunction. Are Autism and SDI similar? And what do you think?
Thank you for your help.

[Kevin Kennedy, Ph.D.]

I can't offer an opinion about diagnosis; this would require much more familiarity with your son and his developmental status. Autistic Disorder, one type of Pervasive Developmental Disorder, is certainly a possibility, given the information you are describing. Sensory Integration Dysfunction alone does not explain the symptoms you are describing, though such a condition can be pasrt of the explanation for his status. Both PDD and SID represent spectrums of problems, with significant variation along the spectrums, both in regard to number of symptoms and level of severity of symptoms.