The term "high functioning Aspergers" has always confused me. I see people use it a lot, but my PDoc said that Aspergers is only ever 'high functioning' in that it is at the upper end of the autism spectrum, but there is no actual Aspergers spectrum. Therefore there cannot be low functioning or high functioning Aspergers, just Aspergers or high functioning Autism.

I had to ask her for clarification on that after reading several blogs where people referred to themselves as having "high functioning Aspergers", but I could never find anything which stated the difference between that and just Aspergers. I wanted to know where I sat on that scale.

One assumption (a personal assumption), is that the phrase became popular as a way to distinguish it more readily from the lower end of the Autism spectrum when speaking to people who don't know very much about it.