A Receptive Language Deficit in Schizophrenic Thought Disorder: Evidence for Impaired Semantic Access and Monitoring

Abstract

Introduction: Two issues have been overlooked in the literature describing the language abilities of schizophrenic patients with formal thought disorder. The first concerns whether such patients have a comprehension deficit in addition to their obvious expressive problems. The second concerns the extent to which any expressive and receptive deficits vary across time. The examination of these issues has important consequences for the likely focus of any underlying cognitive deficit in thought disorder. Method : The current study used a cognitive neuropsychological case-study approach to examine the expressive and receptive language abilities in a schizophrenic patient (TC) with severe formal thought disorder. Results : Expressive (naming) and receptive (word and sentence comprehension) language abilities were tested across time. TC's naming ability was inconsistent across both time and modality (i.e. to-picture and to-description). He also showed a severe comprehension deficit that was highly variable across time. Further testing revealed that the comprehension deficit did not reflect a disorder of working memory, but stemmed directly from impaired access to word meaning. Conclusion : It is suggested that a central semantic memory deficit would most parsimoniously account both for TC's expressive and receptive language problems. Moreover, this deficit appears to affect semantic access rather than a degradation of the semantic knowledge base itself.