The blind, autistic young man I have been teaching for many years, now in his early 20's, loves Bartok's For Children, I and II. At first it was a struggle to get him to accept dissonance into his musical world, though I was determined to give him access to more than just a superficial experience of sound. He is, though severely mentally and physically disabled, a human being with a full range of emotions which he is unable to express verbally.
Yesterday I was teaching him a new piece - as he does not read Braille, this entails his learning it by ear. As I played the melody for him he responded: "Opera!" then "Placido Domingo!" I was overwhelmed. It turns out he has a CD of Domingo singing arias, but surely not this Hungarian folk song. That he made the connection is all the indication I need that I was right to insist on this wide range of music being central to his life.