Dave
I think that what you get is that some special needs people, find music something they love with a passion. This may be particularly true with people who are Aspbergers. They tend to be brilliant with one subject and as such are hopelessly obsessive about it.

My daughter who is Autistic with learning difficulties and not considered aspbergers, was amazingly good at picking up how to play keyboard. As such when she is concentrating on soemthing she enjoys, is is almost like she is single tasking and consequently listens and soaks up what is told and taught and she has this amazing memory capabilty. Unfortunately she got bored with playing the keyboard, but we still leave it around in case she ever gets the desire to play again.

Having said all of that and bearing in mind that through Faldingworth live I meet many performers, I have only come across 2 who I would with confidence class as Aspbergers and they have learnt to overcome their problems, enough to go on stage. Don't ask me who they are, becuase I will not divulge that.

So I would say that many artist's do not have learning disabilities.

What is interesting, is that I see fine singer's or musician's who seem to lack self esteem and do not beleive they are as good as they are.

That doesn't mean that they have learning disabilities. They may have issues such as depression etc, but I don't think that would be classed as learning disabilities.