From letters to words: procedures for word recognition in letter-by-letter reading.

There are two alternative interpretations of how word recognition is accomplished in letter-by-letter reading. One postulates that it relies on the spelling system operating "in reverse," whereas the other claims that it is mediated by the reading system. Because of the close association between patterns of reading and spelling in previously reported cases of letter-by-letter reading, both hypotheses may be considered equally plausible. We now report a patient with letter-by-letter reading who demonstrated a striking dissociation between reading and spelling. Our observations in this patient argue against the concept of "reading via spelling" and suggest that word recognition in letter-by-letter reading is mediated by the orthographic input lexicon used in normal reading.