Abstract Derya Cokal 20 March 2019
Title: Linguistically Profiling Schizophrenia with/without Formal Thought Disorder
Abstract: While formal thought disorder (FTD) clinically manifests as disorganized speech, there have been few investigations of its linguistic properties. In this talk, I will discuss three ways in which disturbance of thought may relate to the referential function of language as expressed in the use of noun phrases (NPs), the complexity of sentence structures, and the syntactic positions of speech dysfluencies. I will report result of three studies, in which we used a comic-strip description task and a sentence-picture matching task to elicit language samples from 30 participants with schizophrenia (SZ) (15 with moderate or severe FTD (SZ+FTD), 15 with minimal or no FTD (SZ-FTD)), 15 first-degree relatives of people with SZ (FDRs) and fifteen neurotypical controls (NC). In the first study, we predicted that anomalies in the normal referential use of noun phrases (NPs) (sub-divided into definite and indefinite NPs), would identify FTD and that FTD would also be linked to reduced linguistic complexity (measured by the number of embedded clauses and grammatical dependents). In the second study, we also predicted disturbances of thought in schizophrenia would manifest in patterns at the level of speech dysfluency and these would also be seen in FDRs. In the third study, we explored whether problems of language may extend to comprehension and clause embedding in particular. Our results demonstrate: (1) FTD can be identified in specific grammatical patterns that provide new targets for detection, early intervention, and neurobiological studies; (2) the temporal organization of speech is an important window on thought-process disturbances.