I think that this may have something to do with the verbal communication difficulties that are associated with ASD's. I experience this sort of thing, too. It drives me crazy, in that I can come up with these amazing ideas, yet, by the time I am able to figure out how to put one small part of the idea into words, I have forgotten the rest, or I let my mind go with the flow, and little, if anything ever gets out. In fact, if I try too hard to verbalize my ideas during one of these periods of deep thought and revelation, I run the risk of my brain locking up on me.
I have learned to deal with my inherent social ineptitudes and found ways to at least get by in this realm, and my sensory issues have abated with age... however, the problem mentioned by the OP has actually intensified with age, and is probably the only thing that I categorically dislike about being an aspie.