Anomalies in Language As a Biomarker for Schizophrenia

Janna N. de Boer; Sanne G. Brederoo; Alban E. Voppel; Iris E.C. Sommer

Disclosures

Curr Opin Psychiatry. 2020;33(3):212-218. 

In This Article

Language Disturbances in Schizophrenia

Impaired verbal communication is one of the key diagnostic features of schizophrenia-spectrum disorders. For reviews on this topic refer to.[11–16] Overall, patients with schizophrenia display a broad range of semantic (i.e. meaning in language) processing disturbances; including difficulties with lexical selection and retrieval,[17] disturbances in priming[18] and reduced proactive inhibition.[12,19] On a discourse level, they show difficulties with coherently generating a narrative, which is thought to reflect an underlying disturbance in taking viewpoints or perspectives.[20] Other related disturbances in schizophrenic language include: neologisms, word approximation,[12] disturbances in cohesion,[21] vague references, missing information and confused references.[15,22] At a syntactic (i.e. grammatical) level, patients with a schizophrenia-spectrum disorder produce sentences with reduced syntactic complexity,[23] less dependents and embedded clauses,[24] and use fewer connective markers.[25] Furthermore, syntactic priming appears to be reduced.[26] Spontaneous abnormal morphology (i.e. using abnormal word forms) in schizophrenia is quite rare.[11] In a test setting, however, patients make more morphological errors than controls.[27] Schizophrenic speech usually has normal segmental phonology (i.e. the articulation of segments such as syllables), although compared with normal speech it contains more hesitations and pauses and longer pauses,[28,29] and the intonation is flat (monotonous).[12]

It has been suggested that language disturbances in schizophrenia arise from abnormal semantic and phonological processing.[30–33] Indeed, neuroimaging data implicate altered frontotemporal semantic and phonological networks in schizophrenia. These include abnormalities in the structure of Broca's, Wernicke's and other frontotemporal regions,[34,35] abnormal white matter language tracts[36–40] and altered functional MRI activation patterns in a variety of language tasks.[41–44] White matter language tract alterations were found in individuals at clinical high-risk (CHR) for psychosis,[45,46] suggesting that these abnormalities precede schizophrenia onset. Indeed, retrospective studies suggest childhood language delays in people who later developed schizophrenia.[47,48] Previous reports have indicated that genetic alternations underlie the neurodevelopment of language abnormalities in schizophrenia.[49,50] The first identified gene involved in language was the FOXP2 gene.[51] Preliminary association studies on FOXP2 polymorphisms and schizophrenia have delivered inconsistent results,[52–54] although epigenetic data do suggest that FOXP2 may be involved in language disorders in schizophrenia.[55] Furthermore, variations in another gene, dysbindin 1 (DTNBP1) have been associated with neural correlates of language production.[56] However, further research is needed to confirm these preliminary results.

Summarizing, biological correlates of language disturbances in schizophrenia have been found in both neuroimaging and genetic studies. Previous research into aberrant language in schizophrenia-spectrum disorders has investigated difficulties arising at the semantic, syntactic and phonological levels of language production. Correspondingly, computational language analyses have focused on these aspects of language output (i.e. semantics, syntax and phonology).

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