Seamon and his team asked JB to take part in tests regarding the epic work where they cued him with two lines selected from anywhere in the poem and asked him to recall the following 10 lines. In one part they picked out lines as they went through the books in order, in another they just chose books at random.
He seemed to stumble on a couple of books when they were tackled sequentially, but generally his verbatim recall was generally above 90% and seemed more consistent when the books were picked out randomly. The team also video-taped one of his live performances and found his average accuracy was between 97% and 98%.
JB is no savant; his accomplishments apparently came from hard work and dedication to the task. Link -via Nag on the Lake