Can Cognitive Development Delays be overcome?

I think it depends on why the child is delayed. Is it neglect, trauma, brain difference, drug exposure, fasd or what not?I have 2 special needs boys. Both with delays in multiple areas including cognitive, emotional, social and developmental areas. Both caused by very different things so the prognosis is different. My youngest, bio, was born with fluid in his ears so he did not hear until he was 9mo. This messed with his sensory system, speech development and over all development. His prognosis is great though. He's caught up in all but a couple of areas and will likely enter kindergarten as a typical kid in the fall of 2012. There is no reason to believe that he won't completely overcome his delays. Our only long term concern is the link between delayed speech and LD, but we're just keeping an eye on that.My oldest, adopted, delay's were caused by all of the above, trauma, neglect, exposure and so on. He's "caught up" by testing standards before, but always falls behind again. So, we did a neuropsych eval a couple years ago and we were told that J would continue to develop and grow but at a slower rate than his peers. We were told we should prepare ourselves for a longer transition to adulthood. He may eventually catch up in some areas, but it will take some time. He's been diagnosed as PDD-NOS and also has prenatal drug/alcohol exposures.He was 4 at placement and I did truly believe at the time that he would catch up with a little time and a lot of love. But since then I've learned so much more about brain development and how its affected by trauma, neglect and so on. I did have to grieve for the loss of my dream of him being "normal" someday, but then I got down to learning how to parent him the way he needed.So, the long winded answer to your question is yes and no. It's not something that can be predicted until you know the child so much better.