Syntactic complexity of spoken language in the diagnosis of schizophrenia: A probabilistic Bayes network model

Silva, Angelica M; Limongi, Roberto; Mackinley, Michael; Ford, Sabrina D.; Alonso-Sánchez, María Francisca; Palaniyappan, Lena

doi:10.1016/j.schres.2022.06.011

Cited by 15 publications

(5 citation statements)

References 81 publications

(88 reference statements)

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“…This finding contrasts most previous studies (43), although Silva et al (44) showed, in an overlapping sample, that while syntactic complexity dropped over time, it was higher at the FEP state. One possible explanation for the contrary findings in most prior studies, apart from illness stage, is that these might have been strongly biased by word count, whereby the schizophrenia group tended to produce shorter sentences probably with less syntactic complexity (21,(44)(45)(46). This motivated our inclusion of the number of words in the GLM model, though the FEP group generated broadly similar quantity of speech, as measured with words, utterances, and lexical categories, likely thanks to the control of speech duration within one minute.…”

Section: Discussioncontrasting

confidence: 99%

“…4A), which predicted the gradient dispersion of the semantic network: FEP exhibited more nodes in higher syntactic trees, and higher fraction scores of phrasal nodes out of word nodes, with the number of words as a covariate. This finding contrasts most previous studies (43), although Silva et al (44) showed, in an overlapping sample, that while syntactic complexity dropped over time, it was higher at the FEP state. One possible explanation for the contrary findings in most prior studies, apart from illness stage, is that these might have been strongly biased by word count, whereby the schizophrenia group tended to produce shorter sentences probably with less syntactic complexity (21,(44)(45)(46).…”

Section: Discussioncontrasting

confidence: 99%

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Changes in the structure of spontaneous speech predict the disruption of hierarchical brain organization in first-episode psychosis

He,

Alonso-Sánchez,

Sepulcre

et al. 2023

Preprint

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Psychosis implicates changes across a broad range of cognitive functions. These functions are cortically organized in the form of a hierarchy ranging from primary sensorimotor (unimodal) to higher-order association cortices, which involve functions such as language (transmodal). Language has long been documented as undergoing structural changes in psychosis. We hypothesized that these changes as revealed in spontaneous speech patterns may act as readouts of alterations in the configuration of this unimodal-to-transmodal axis of cortical organization in psychosis. Results from 29 patients with first-episodic psychosis (FEP) and 29 controls scanned with 7T resting-state fMRI confirmed a compression of the cortical hierarchy in FEP, which affected metrics of the hierarchical distance between the sensorimotor and default mode networks, and of the hierarchical organization within the semantic network. These organizational changes were predicted by graphs representing semantic and syntactic associations between meaningful units in speech produced during picture descriptions. These findings unite psychosis, language, and the cortical hierarchy in a single conceptual scheme, which helps to situate language within the neurocognition of psychosis and opens the clinical prospect for mental dysfunction to become computationally measurable in spontaneous speech.

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Section: Discussioncontrasting

confidence: 99%

Section: Discussioncontrasting

confidence: 99%

Changes in the structure of spontaneous speech predict the disruption of hierarchical brain organization in first-episode psychosis

He,

Alonso-Sánchez,

Sepulcre

et al. 2023

Preprint

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“…Additionally, our observations raise the question of whether patients with higher developmental disruption form the subgroup with cortical and linguistic impoverishment since syntactic complexity is a phenomenon that develops during childhood (Givon, 2009;Frizelle et al, 2018) and reaches a plateau around the age of 20 (Nippold et al, 2014). If developmental disturbances during childhood and adolescence lie in the pathogenesis of schizophrenia and can be detected using NLP tools (via progressive aberrations in syntactic complexity; see Silva et al, 2022), this may provide a promising avenue for early identification.…”

Section: Discussionmentioning

confidence: 85%

Widespread cortical thinning, excessive glutamate and impaired linguistic functioning in schizophrenia: A cluster analytic approach

Liang

Silva

Jeon

et al. 2022

Front. Hum. Neurosci.

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IntroductionSymptoms of schizophrenia are closely related to aberrant language comprehension and production. Macroscopic brain changes seen in some patients with schizophrenia are suspected to relate to impaired language production, but this is yet to be reliably characterized. Since heterogeneity in language dysfunctions, as well as brain structure, is suspected in schizophrenia, we aimed to first seek patient subgroups with different neurobiological signatures and then quantify linguistic indices that capture the symptoms of “negative formal thought disorder” (i.e., fluency, cohesion, and complexity of language production).MethodsAtlas-based cortical thickness values (obtained with a 7T MRI scanner) of 66 patients with first-episode psychosis and 36 healthy controls were analyzed with hierarchical clustering algorithms to produce neuroanatomical subtypes. We then examined the generated subtypes and investigated the quantitative differences in MRS-based glutamate levels [in the dorsal anterior cingulate cortex (dACC)] as well as in three aspects of language production features: fluency, syntactic complexity, and lexical cohesion.ResultsTwo neuroanatomical subtypes among patients were observed, one with near-normal cortical thickness patterns while the other with widespread cortical thinning. Compared to the subgroup of patients with relatively normal cortical thickness patterns, the subgroup with widespread cortical thinning was older, with higher glutamate concentration in dACC and produced speech with reduced mean length of T-units (complexity) and lower repeats of content words (lexical cohesion), despite being equally fluent (number of words).ConclusionWe characterized a patient subgroup with thinner cortex in first-episode psychosis. This subgroup, identifiable through macroscopic changes, is also distinguishable in terms of neurochemistry (frontal glutamate) and language behavior (complexity and cohesion of speech). This study supports the hypothesis that glutamate-mediated cortical thinning may contribute to a phenotype that is detectable using the tools of computational linguistics in schizophrenia.

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“…To this end, specific 'Natural Language Evaluation' approaches to adjudicate the outputs of different DLN models for their psychosis-likeness will be needed. Certain candidate evaluation metrics for disorganised speech in psychosis include reduced lexical predictability (or perplexity (88,89) ) and reduced syntactic complexity (90). These are unlikely to be sufficient in isolation for selecting DLNs for further study.…”

Section: A Program Of Psychosis Research With Nlgmentioning

confidence: 99%

Studying Psychosis Using Natural Language Generation: A Review of Emerging Opportunities

Palaniyappan¹,

Benrimoh²,

Voppel³

et al. 2023

Biological Psychiatry: Cognitive Neuroscience and Neuroimaging

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Syntactic complexity of spoken language in the diagnosis of schizophrenia: A probabilistic Bayes network model

Cited by 15 publications

References 81 publications

Changes in the structure of spontaneous speech predict the disruption of hierarchical brain organization in first-episode psychosis

Changes in the structure of spontaneous speech predict the disruption of hierarchical brain organization in first-episode psychosis

Widespread cortical thinning, excessive glutamate and impaired linguistic functioning in schizophrenia: A cluster analytic approach

Studying Psychosis Using Natural Language Generation: A Review of Emerging Opportunities

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