People who read in braille take in text in a very linear fashion. The nature of the braille system requires it. The DOTS newsletter, put out by the American Foundation for the Blind (AFB), has a lovely piece about the importance of braille transcribers. Braille transcribers have the challenging job of formatting complex documents into a linear format before they are embossed in braille.
Check out this piece and the rest of the DOTS newsletter at http://www.afb.org/Section.asp?SectionID=6&TopicID=19&DocumentID=5348#thank
