L....my son is now five and still have problems with low tone, but he has compensated for a lot of it over the years. He has global developmental delays of about 18 months, so he is now developmentally about 3 1/2 on nearly every front. It has been a long road, but he is really doing well overall. The problems with the low tone only show up here and there...we now have him working with a private OT largely to address core strength and severe global sensory issues. For what it's worth...once they addressed and started treating my son's sensory issues, many of his other areas of concerns showed rapid improvement. To give you some context, when we had Riley evaluated by EI at 18 months, he did not walk, he was completely non-verbal, he ate only sparingly (his weight was 16 lbs. at that time and yes, he was full-term and over 7 lbs. at birth), and NEVER napped - at night if he slept 6 hours we were having a great night! Now he runs and climbs and talks non-stop. He only eats a select few foods, but what he does eat, he eats well and he sleeps 10-12 hours at night.
Feel free to contact me privately if I can be of help. We've been down this road - it's a long road, and a lot of the baby steps (no pun intended) take longer and require a lot more work, but they mean so much when they are achieved. We really learned to appreciate how hard he was working for everything! It took a long time for me to put a lot of that in context - and there are still days that are hard...but he has come so far and is doing so well. If you had told us when he was two that he would be where he is now, we would have looked at you like you had two heads! :) The developmental ped should be very helpful - that is one avenue we have not taken with Riley, but it's still on the table - CHOP is an amazing facility - we are lucky to live in an area where so many incredible medical centers are within pretty easy driving distance. Good luck!!!