My 11 yo has Asperger's Syndrome (High Functioning Autism). He is constantly talking and repeating the same thing over and over.
His current "obsession" is cars. He reads nonfiction about cars constantly (I've come to realize that many of these nonfiction books are truly "living books" as the authors are passionate about their subjects).
He will not read fiction, but he will listen to books I read aloud or books on tape that we do together. I have just come to the place of saying "it's okay" that he's not a fiction reader (my husband isn't either).
In a sense, he is constantly narrating (orally) because he gets so excited about what he's reading that he wants to tell me or someone else. But he often repeats himself to the point where we get tired of hearing the same thing 100 times. 
I sometimes have him do PowerPoint presentations about the cars, which I see as a form of written narration. His mechanical writing skills are weak, so he would rather type, which is fine with me.
Just wondering what others do with Special Needs children and other ideas to harness this "gift of gab".
Nanci
. It mixes things up for him and allows for some hands-on/interactive narrating. Here's what I use: