Word Meaning Blindness Revisited.

Lambon Ralph, Sage, and Ellis (1996) described a patient, JO, who had impaired understanding of written words in the presence of normal comprehension of objects and spoken words.She was able to recognise letters and could differentiate written words from nonwords in lexical decision tasks. JO's ability to read aloud all types of words and nonwords was also intact. Although JO's understanding with silent reading was compromised, her comprehension was dramatically improved when she was permitted to read words aloud. Lambon Ralph et al. interpreted this disorder as due to a partial disconnection of the visual input lexicon from the semantic system and labelled the disorder "word meaning blindness". JO's word meaning blindness resulted from a progressive illness that provided us with an opportunity to investigate the pattern of deterioration in this apparently rare form of dyslexia. Over a period of one year we tested her on three occasions with a battery of neuropsychological tasks designed to assess her comprehension across modalities and her ability to read aloud various words, including words with exceptional spelling-to-sound correspondences. The main finding of this longitudinal assessment was a further reduction in her understanding of written words read silently with a preservation of spoken word comprehension. Throughout the period there was little or no change in JO's ability to read aloud words and nonwords, including exception words. The implications of this pattern for theories that emphasise the role of semantics in reading aloud are discussed.