I was TOP in 1996 and was invited to join EXP in 1997. I know that VIP predated 1996 but I didn't realize that TOP may have also.
As the name implies, I was told that TOP was a group of the "top" (less than 1%) of the fliers in each of AA's then major cities (DFW and ORD for sure, and I think NYC and LAX). I never received any formal documentation of the program but I did receive great, personal service.