Wow, interesting. Yes, I have read the other thread about fevers and development bursts. My dd also does show improvement in her behavior when she has a fever as well. She shows major behavior improvements, is cooperative, more even tempered, helpful, etc. I'm surprised to see that their are many of us that have kids with high fevers with unknown causes.
when ds has a fever, he behaves and babbles well, at least until it gets to high, for him its around 101, he has a low threshold, and will get extremely lethargic and wont eat/drink, and has no idea what he wants, he wants comforting but doesnt want to be touched etc. So we use tylenol alot.
My boys got lots of misc, random temperatures as wee ones. I remember our first pedi saying "think of all the junk their bodies have to learn about, it's no wonder little kids have runny noses and unexplained high temps every now and then". IMO I don't think it's necessarily a function of autism, but rather a function of the body doing it's job to stay healthy, and perhaps a functional side effect is a fun little developmental burst for some children.