I do not believe in performance anxiety at all!
I believe in becoming conscious that people are around you, in being aware of what people think of you etc.. In other words: distraction!
I always taught my students that a performance is only a reflexion on their practice. No one ever practices super poorly and performs amazingly well, and/or vice versa.. that's a myth!!!
Students need to have millions of information to fulfill their brain when they perform and check that all of it is done at all time (while they perform). They need to be doing three things at the same time:
1) Did I do well?
2) What am I suppose to do right now?
3) What am I suppose to do next?
All three in realtime!
I know...it's exhausting.. I am a concert pianist.. I have lived this my whole life..
The only time I had something close to "stage fright" was, when I was totally unprepared (and I learned it the hard way, trust me)..
So let's teach our kids (or ourselves as a matter of fact) to have:
1) so many things that we had to achieve
2) that we are achieving now
3) that we have to achieve in the next few seconds that truly the brain won't have the time (or the luxury) to think about what people think about us/them!
My most successful experience was a student (in College, she was 20+), who couldn't even recognize where the A (above middle) C was, because she was panicking so much.... 3 years later (I never said it was fast to implement) she played the 2nd mvt. of the famous C Major Sonata from Mozart without even one glitch and it was gorgeous musically too!
Thank you very much.