By the way, the digressions I have just mentioned can be mistakenly seen as a sign of having ADD. However, the ADD mind begins all learning situations already in these digressions, then into bluntness (the I am not interested in learning responses), while the Asperger's mind only ends up there when there is no precise way to understand something they are trying to learn (AS kids love learning, at least about their special interests, e.g. the insect parts AND the insect song; a very typical cross sense AS trait; everything with the same overall title gets included in the same interest.)
Kids with Asperger's and adults with Asperger's also share another quality; throwing tantrums when being asked to change the official way things are done, arranged, managed, or learned. And while kids with OCD share some of this, they do not usually have the "special interest" thing; meaning, your son's desire to learn in such fine detail. This quality; precisely learning about things, differs markedly from the OCD quality of precisely arranging things. This in fact would be enough for me to tend toward the AS diagnosis over and ADD or an OCD diagnosis.
As for the PDD-NOS, many adult AS clients also have these same odd features; ticks and so on. However, when combined into a comprehensive pattern, the AS fractal emerges as the clear diagnosis.
Finally, you might wonder why I focus so much on getting the right diagnosis. I do this as getting help early is one of the main factors in improving the outcome. I, myself, have AS and have managed to see past much of what I have described, but only because my "special interest" is human nature, a totally random but useful way out of the usual narrow focus.
As a child, I was very similar to how you describe your son.
As a man, who else would write thousands of pages on human nature simply to help folks.
Lincoln, Jefferson, DaVinci and Socrates definitely had AS. And while most folks with AS will not achieve anything like what these also geniuses did, you son is way about average in intelligence. If you can develop in him an equal measure of creativity, then he may well turn out similarly.
Warmly,
Steven
P. S. For a more detailed version of my diagnostic criteria, you can find a more complete article on my site at:
Steven Paglierani is a writer, teacher, personality theorist, and therapist whose work on learning and human consciousness is read weekly by thousands all over the world. He is the author of Emergence Personality Theory, and his mission is to make the world better for children by restoring and deepening their love of learning.