Remain cautious about concluding that any one symptom is indicative of a disorder. In the presence of other symptoms, the behavior you describe might lead in the direction of the possibility of a disorder along the Pervasive Developmental Disorder spectrum (certainly not Autistic Disorder). It's not clear that the behavior serves a self-stimulating function. It might be more of a self-soothing, rather than self-stimulating, behavior. Some of the content of your note indicates a certain rigidity in his thinking. If this is true, it will bear watching. At this point, it is not at all clear that his symptoms warrant any diagnosis along the PDD spectrum. And, if such a condition is considered, it would be at the very high end of that spectrum. At the bottom line, I think you'll have to see how the next two years progress. Thus far he is managing the major develpmental challenges of his age, and that is the most important consideration.
Doc, self stims are self soothing and is a means of regulating your environment when the environment because to chaotic.
The reader makes a good point - i.e., self-stimulating behaviors may serve a purpose of soothing. But this is not always the case. Are they often a reaction to what the child experiences as chaos in the world around them? Yes, often they are. But it is important to distinguish between the self-stimulating behaviors engaged in by PDD-spectrum children and self-soothing behaviors or children who do not display such conditions. It might be more correct to say that the self-stimulating behaviors of the PDD-spectrum children are adaptive attempts (though not terribly successful).
This is how I would describe self stim behavior in ASD with an analogy:
Suppose you are listening to your stereo and you turn up the volume. If you keep turning up the volume, at some point the sound starts to crackle and become distorted. When you have reached the "distortion" point in the volume, the music no longer is tolerable. It doesn't matter if you turn the volume higher because at that point, it simply doesn't work. The only way to make the music sound good again is to turn the volume down.
In an ASD child, when the environment becomes "too much", they attempt to "turn down the volume" by self stimulatory means. Self stims are their method of resetting the volume. If they are allowed to stim a little and their parents set time and place limits on the stimming, it is quite successful at resetting the "volume". It is only then that they can be ready to start interacting again. What you don't want to do is allow them to stim just to stim. The stimming has to be for a purpose and they need to know when the appropriate time is to stim. We actually give him a clock and tell him at night "you have 5 minutes of stim time". Then we leave him alone. When the 5 minutes are up, he has to stop. What's funny is that sometimes he doesn't want to stim during this "free stim" time. But, when the 5 minutes are up, he will start to stim and then look at us with a mischevious smile to get a reaction from us. Very boy-like behavior in my belief. One of his favorite stim activities is to line up various picture cards he likes. If he is doing this outside of stim time, we stop him and ask "what are you doing?" We'll tell him no lining. Then he'll say he's counting (followed by him counting the pictures 1...2...3..etc.). It's obvious that he wasn't lining in order to count the pictures. However, he knows we are working on his counting so he will use the counting excuse so he can continue to line the pictures. He's quite smart.
So, in my child's case, stimming can be quite successful. However, I must say that we only allow him to stim at home, not out in the public and he is pretty good about following that rule and I think he understands why that rule has been established.
I don't think this will always work for every ASD child, but I would say it works in about half of them. The spectrum is very wide and those children who have a lot more sensory difficulties will need more time to stim than those who have small sensory issues.