Agrammatism in a case of formal thought disorder: Beyond intellectual decline and working memory deficit

Abstract

Previous studies have suggested that naming and syntactic deficits in formal thought disorder may be related to global cognitive decline. This article reports the case of a patient, FM, with formal thought disorder schizophrenia who presents disproportionate deficits in receptive and expressive grammar with respect to his intellectual level of functioning. Syntactic and morphologic components of expressive grammar appeared equally impaired. Deficits in language comprehension were observed independently from working memory limitations. FM showed preserved grammaticality judgment, but defective sentence comprehension where semantic context does not provide heuristics for assigning thematic roles, but syntactic knowledge is essential. These atypical results are discussed within a neurodevelopmental aetiological model of formal thought disorder.

Keywords:

• Formal thought disorder
• Agrammatism
• Sentence comprehension
• Syntactical analysis
• Working memory

Acknowledgments to Dr Jocelyne Cournoyer for referral of this fascinating patient. I am also thankful to the anonymous reviewers for their helpful comments.