Deep dysphasia: A study of errors in oral and written production

We report the case of an Italian patient who, in repetition tasks, produced a large number of semantic paraphasias and had a severe impairment for non-words, fulfilling the criteria for 'deep dysphasia'. The presence of good auditory and visual comprehension of single words, as well as the results of verbal description and drawing tasks, provided evidence for a post-semantic locus of impairment. The combination of an output lexicon disorder with an impairment of the sublexical auditory-to-phonological conversion pathway can account for this clinical picture. The results of an error analysis in the different output modalities, as well as a follow-up study, are interpreted within the framework of an interactive spreading activation model of lexical retrieval in naming and repetition. In particular, an abnormally rapid decay rate of linguistic representations can account for the large number of semantic errors in repetition, and for the profuse production of phonologically related errors in all output tasks.