My guess, without consulting any media studies, is that the fact Lorna Wing (the psychiatrist who popularized Asperger syndrome and founder of the UK's "National Autistic Society") is a large reason why it is so much more known in the UK. That and the fact that British media, in general, seems to be a lot better than what comes out of North America.
I find this post rather ironic considering that, even though the British Media may be better at reporting on Asperger's, they seem to be their toughest critic.
Quote:
Asperger syndrome - a form of autism characterised by difficulties dealing with people and social situations - affects close on one in every 100 people in Britain.
With 500,000 people in the UK alone having the condition, it's a lot more common than the disability's current profile would suggest.
Ladyhawke speaks about Asperger's
To digress into media analysis for a bit, I think this demonstrates a positive quality of British media lacking in the United States: self-criticism. This may be too general a point to make on the basis of one article used as an anecdote for one issue, but it is still interesting to consider.