http://www.cdc.gov/ncbddd/autism/overvi ... iteria.htm
This is the criteria they use in the U.S. If you scroll down, it gives you the criteria for Asperger's, which is slightly different.
When my son was 6, some parents online told me that the things I described about him sounded a lot like Asperger's, and I should check that out. So, I read the criteria, and I thought, "Well...I'm not so sure" because it wasn't easy to pigeon-hole him into that. He had a lot of odd behaviors, but I didn't see him as meeting the criteria in category "A".
But when he was evaluated by a professional (who did a very extensive evaluation, so I trust her judgment), she said, "Definite Asperger's".
Now, if I look at the Asperger's criteria in regard to myself, I feel the same way. The "A" category criteria are all things that I know describe me a little bit, but it's hard to be sure. There are some people who know me, who would insist that none of those things apply to me, because I'm pretty "normal" around them. If I can't be somewhat "normal" around someone, I stay away. I've never really known anyone who sees me in a variety of settings, though, so they wouldn't be able to say. B1 and B3 describe me, but I keep that to myself. I laid in bed awake for hours last night, replaying the Alan Rickman and Geraldine McEwan scenes from "The Barchester Chronicles" in my mind, as I tend to do often...but people don't KNOW that I do that. LOL! Well, okay, you do, now! I'm not sure if I know anyone who would describe me as doing those things, because I'm not going around squinting my eyes and saying , "That...ODIOUS woman!! !" all the time. I'd like to, though!
Except it interferes with my ability to get a good night's sleep, and I sometimes burn dinner because of the same kind of distraction.
And C, well...I've been fired from a lot of jobs because I was "slow" or had a "bad attitude", even though I was the ONLY ONE who DIDN'T have a bad attitude. So, there's that.
Sorry, here I am trying to diagnose myself. D'oh! That's not what your post was about!
I guess my point is there are official diagnostic criteria, but it's subjective. How does someone determine what a "significant impairmant" is?