The Semantic Underpinnings of Speech Disorganization in Schizophrenia

Abstract

Effective communication relies on shared semantic representations and their context-sensitive retrieval. Accordingly, difficulties in communicating coherently, as seen in some patients with schizophrenia, may reflect impairments at the level of semantic structure or the retrieval process operating on this structure. Disentangling these components is challenging. Here, we address this problem using a word association task and magnetoencephalography (MEG), allowing us to examine behavioral markers of semantic structure and retrieval as well as semantic representation in the brain. For the latter, we detail an approach that contrasts the brains encoding of concepts as predicted by generic versus personalized semantic models. In so doing, we provide converging evidence for semantic structure idiosyncrasy in patients with schizophrenia who also exhibit speech disorganization. The findings advance our understanding of the semantic underpinnings of speech disorganization in schizophrenia, while also revealing the potential of using personalized semantic models to explain neural representation and behavior.