M.A.
Hi-
There is hope. My son was referred to EI around 1 year of age for eating issues, and consequently, he was eventually diagnosed with SPD. He will be 4 next week, and has made wonderful progress with the OT, which has helped with his communication. Right around 18 months, there was a whole week where he wouldn't look at me or talk to me, and I worried about autism, but it passed.)
With my son, I've noticed when he is having difficulty with all the sensory stuff, he tends to slip into his own world, and will either seem to ignore everything I say, or talk continually and repetitively about one subject-usually smoke alarms and fire extinguishers. I think it is just too overwhelming to deal with more than just the input from the environment sometimes. Is your son getting OT with a good OT, trained in sensory integration disorder? Were you given a sensory diet for your child? This will help. Otherwise, the communication aspect may take time. The sensory issues need to be dealt with first, then the communication will come. SPD gets in the way of children developing normally.
The Out of Sync Child book is by Carol Stock Kranowitz. It is considered "the bible" in terms of being the first to really deal with this disorder. There are other books, however. I like Sensational Kids by Lucy Jane Miller(it was easier for me to read and understand); Raising a Sensory Smart Child by Lindsey Biel and Nancy Peske is also good, as well as The Sensory Sensitive Child (I think...I forget who by....)
There are also several websites dedicated to this disorder. Let me know if you'd like the URL's, and I will send you the ones I know about. I have heard that the listening program works wonders. We haven't seen it with our son personally yet, but I've heard almost "miracle" stories from other parents. Good luck, and talk to your OT. If you don't have one, demand one from EI-you can do that!