My nephew has aspergers syndrome, and he writes me letter often, and they are all very long, and repetitive. His spelling and grammer is always perfect, but he talks a lot about old cars, and what year they were made, and what models are what.

Fortunately, he never did the repetitive rocking or banging.
He is sort of like the rain man, in that he is brilliant at math, and if you tell when you were born, he instantly knows what day of the week that date was.

He is not very socially mature, though, and his voice is sort of a sing-song.

My sis and her husband had to pay for special schooling for him after sixth grade, and it was very expensive. He now lives in a group home (he is in his 30's now), but he comes home for a weekend at least once a month. He is a very happy individual.