Umm, I wouldn't say they disappear, persay. More like the person with SPD adapts. It never goes away, and there's always the ocassional bad day. For it to go away, they'd have to figure out a way to give us new nervous systems, and even then most of us probably wouldn't want them. I don't. So, I guess not. Get better, yeah, maybe, hopefully, but it never goes away, no.
I really appreciated reading that sensory processing deficits can be inconsistent; meaning, present one day and not the next. That is absolutely my experience