Word Meaning Blindness: A New Form of Acquired Dyslexia

We report the case of a patient, JO, who showed intact perception and comprehension of spoken words but who was impaired at accessing the meanings of words she was required to read silently. Letter recognition and written lexical decision were both intact, as was her reading aloud of both words and nonwords. JO's visual comprehension deficit suggests an impairment in mapping between representations in the visual input lexicon and the semantic system. This appears to be the counterpart in reading of "word meaning deafness" (a disorder of spoken word recognition in which patients can perceive spoken words and make auditory lexical decisions but have problems comprehending heard words, despite good comprehension of written words). Hence we refer to this new form of acquired dyslexia as "word meaning blindness." JO's comprehension of words she read aloud was much better, presumably because receding print into sound enabled her to use her preserved auditory comprehension processes to access meanings. She seemed unable, however, to use "inner speech" to access speech comprehension processes covertly, and further testing indicated a separate impairment of inner speech, which had the effect of making her word meaning blindness more apparent.