Disordered discourse in schizophrenia described by the Structure Building Framework

Narrative Discourse Performance in Traumatic Brain Injury: Does Story Comprehension Predict Story Retelling?

PURPOSE

Little is known about the relationship between discourse comprehension and production in traumatic brain injury (TBI), especially for spoken language. This study examined to what extent narrative discourse comprehension accounts for narrative discourse production outcomes (story grammar, story completeness). A secondary aim was to provisionally test an assumption of a discourse model, the structure building framework (SBF), that discourse comprehension and production share cognitive processes by investigating the strength of the relationship between them.

METHOD

Twenty-one individuals with TBI completed story comprehension and story retelling tasks. Discourse measures included the Discourse Comprehension Test, a picture story comprehension task, story grammar, and story completeness. Correlational and multiple regression analyses were performed using comprehension measures as predictors for production measures.

RESULTS

There were significant moderate-to-large correlations between all comprehension and production measures. Comprehension measures approached but did not reach significance for predicting story grammar performance but strongly predicted story completeness outcomes.

CONCLUSIONS

The story comprehension measures likely tapped content aspects of discourse more so than organization. Results provided support for a link between content-focused discourse comprehension measures and discourse production outcomes, which may have clinical implications for approaches to discourse intervention. Findings were interpreted as providing preliminary support for the SBF's claim that discourse production deploys the same processes involved in discourse comprehension.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.26338045.

Contribution of Working Memory and Inferencing to Narrative Discourse Comprehension and Production in Traumatic Brain Injury

PURPOSE

The goal of this study was to identify some potential key cognitive and communicative processes underlying narrative discourse ability following traumatic brain injury (TBI). Specifically, this study (a) investigated the contribution of working memory (WM) and inferencing to narrative discourse comprehension and production; (b) tested key assumptions posited by the Structure Building Framework (SBF), a discourse model; and (c) evaluated the potential for inferencing to contribute to discourse ability beyond a shared variance with WM.

METHOD

Twenty-one individuals with TBI completed six tasks yielding seven measures: verbal and nonverbal WM updating (WMU-V and WMU-NV, respectively), predictive inferencing, the Discourse Comprehension Test (DCT), a picture story comprehension (PSC) task, and story retelling (story grammar and story completeness). Regression analyses were performed using WM and inferencing as predictors for narrative performance.

RESULTS

WM measures were significant predictors of DCT performance and approached significance as predictors of PSC. Inferencing approached significance as a unique predictor for the DCT and story completeness. WMU-V and WMU-NV were highly collinear, and neither WM measure predicted discourse outcomes over and above the other's contribution.

CONCLUSIONS

WM was more strongly associated with comprehension processes, whereas inferencing may be associated with both comprehension and production outcomes. Findings were interpreted as supporting SBF assumptions of domain generality of cognitive processes and mechanisms involved in discourse while also challenging assumptions that the same cognitive substrates are marshaled for comprehension and production processes.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.23148647.

Pragmatic deficits in patients with schizophrenia and right hemisphere damage: A pilot study

BACKGROUND

While pragmatic deficits are well documented in patients with schizophrenia (SCZ) and right hemisphere damage (RHD), there is a paucity of research comparing the pragmatic deficits of these two groups. Do they experience similar cognitive dysfunction or is there a dissociation between the two patient groups?

AIMS

To investigate the nature of pragmatic deficits in these two groups and to gain an understanding of the underlying cognitive mechanisms that might be associated with these deficits to further future investigations.

METHODS & PROCEDURES

A total of 60 participants (15 patients with SCZ; 15 with RHD; 30 (15 + 15) healthy controls (HC) were administered the Bengali Audio-Visual Test-Battery for Assessment of Pragmatic Skills.

OUTCOMES & RESULTS

Both SCZ and RHD patients were found to have significant pragmatic deficits compared with their matched controls. SCZ patients were found to score significantly better than the RHD group in six out of the 10 pragmatic skills when controlled for age and education. Discriminant function analysis was performed and 86.7% of the cases (HC = 100%, SCZ = 73.3% and RHD = 86.7%) were correctly reclassified into their original categories using the test scores.

CONCLUSIONS & IMPLICATIONS

The study suggests that there is heterogeneity in the nature of the pragmatic breakdown within and across patient groups. Therefore, individualized restorative measures targeting the disrupted cognitive mechanism(s) might help elevate pragmatic competence and enhance the social functioning of patients with pragmatic deficits.

WHAT THIS PAPER ADDS

What is already known on the subject Pragmatic deficits are common in adults with cognitive impairments of different etiologies. However, few studies have explored pragmatic deficits across clinical populations. Consequently, very little is known about the nature of pragmatic deficits in patients with schizophrenia and right hemisphere damage. What this paper adds to existing knowledge This work offers preliminary data on pragmatic difficulties in patients with schizophrenia and right hemisphere damage. This study overrides the boundaries of traditional classifications and evaluates pragmatic difficulties in these two clinical populations with reference to the underlying cognitive mechanisms, which might be disrupted. What are the potential or actual clinical implications of this work? The study adds a transdiagnostic perspective suggesting that there might be heterogeneity in pragmatic deficits, both within and across patient groups, and stresses the need for individualized therapy.

Differences in fractal patterns and characteristic periodicities between word salads and normal sentences: Interference of meaning and sound

Fractal dimensions and characteristic periodicities were evaluated in normal sentences, computer-generated word salads, and word salads from schizophrenia patients, in both Japanese and English, using the random walk patterns of vowels.　In normal sentences, the walking curves were smooth with gentle undulations, whereas computer-generated word salads were rugged with mechanical repetitions, and word salads from patients with schizophrenia were unreasonably winding with meaningless repetitive patterns or even artistic cohesion. These tendencies were similar in both languages. Fractal dimensions between normal sentences and word salads of schizophrenia were significantly different in Japanese [1.19 ± 0.09 (n = 90) and 1.15 ± 0.08 (n = 45), respectively] and English [1.20 ± 0.08 (n = 91), and 1.16 ± 0.08 (n = 42)] (p < 0.05 for both). Differences in long-range (>10) periodicities between normal sentences and word salads from schizophrenia patients were predominantly observed at 25.6 (p < 0.01) in Japanese and 10.7 (p < 0.01) in English. The differences in fractal dimension and characteristic periodicities of relatively long-range (>10) presented here are sensitive to discriminate between schizophrenia and healthy mental state, and could be implemented in social robots to assess the mental state of people in care.

Discourse Measures to Differentiate Between Mild Cognitive Impairment and Healthy Aging

Although subtle discourse declines in people with mild cognitive impairment (MCI) have been reported, heterogeneous measures and tasks among the MCI discourse studies have yielded widely varying outcomes. The present study aimed to first, identify discourse measures that aid the differentiation among people with amnestic MCI (aMCI), people with non-amnestic MCI (naMCI), and cognitively healthy control (HC) participants, and second, delineate the cognitive functions related to such discourse measures. Three discourse tasks (an episodic narrative, a planning task, and a picture description) were performed by 30 aMCI, 22 naMCI, and 21 HC participants. Samples were analyzed using six categories of 15 measures, namely coherence, cohesion, proposition, grammaticality, lexicality, and fluency. The statistical analyses included (1) a multivariate analysis of variance for group comparison; (2) binary simple logistic regression and receiver operating characteristic curve analysis for differentiation between two groups; (3) binary multiple logistic regression for being diagnosed with naMCI or aMCI with the minimum number of predictors; and (4) Pearson correlation analysis for identifying the cognitive functions associated with the discourse measures. The proportion of cohesive words and propositional density in aMCI participants were worse than those in naMCI participants. Global coherence, the proportion of cohesive words, and the proportion of dysfluencies and pauses in naMCI participants were lower than those in the HC participants. Global and local coherence and the proportion of cohesive words, cohesive ties per utterances, propositional density, and dysfluencies and pauses in aMCI participants were worse than those in the HC participants. The aforementioned measures were demonstrated to be effective predictors for classifying groups by receiver operating characteristic curve analysis. In addition, the proportions of cohesive words and pauses were common discourse measures for differentiation between naMCI and HC participants or between aMCI and HC participants using binary multiple logistic regression. According to the correlation analysis, memory and executive functions are needed for coherent, cohesive, and efficient discourse productions in MCI. The detailed description of discourse performances in this study will aid the characterization of the declined language abilities of MCI participants and also the understanding of the cognitive functions involved in discourse performance in MCI.

Language context processing deficits in schizophrenia: The role of attentional engagement

Individuals with schizophrenia exhibit problems in language comprehension that are most evident during discourse processing. We hypothesized that deficits in cognitive control contribute to these comprehension deficits during discourse processing, and investigated the underlying cognitive-neural mechanisms using EEG (alpha power) and ERPs (N400). N400 amplitudes to globally supported or unsupported target words near the end of stories were used to index sensitivity to previous context. ERPs showed reduced sensitivity to context in patients versus controls. EEG alpha-band activity was used to index attentional engagement while participants listened to the stories. We found that context effects varied with attentional engagement in both groups, as well as with negative symptom severity in patients. Both groups demonstrated trial-to-trial fluctuations in alpha. Relatively high alpha power was associated with compromised discourse processing in participants with schizophrenia when it occurred during any early portion of the story. In contrast, discourse processing was only compromised in controls when alpha was relatively high for longer segments of the stories. Our results indicate that shifts in attention from the story context may be more detrimental to discourse processing for participants with schizophrenia than for controls, most likely due to an impaired ability to benefit from global context.

Spared and impaired spoken discourse processing in schizophrenia: effects of local and global language context

Individuals with schizophrenia are impaired in a broad range of cognitive functions, including impairments in the controlled maintenance of context-relevant information. In this study, we used ERPs in human subjects to examine whether impairments in the controlled maintenance of spoken discourse context in schizophrenia lead to overreliance on local associations among the meanings of individual words. Healthy controls (n = 22) and patients (n = 22) listened to short stories in which we manipulated global discourse congruence and local priming. The target word in the last sentence of each story was globally congruent or incongruent and locally associated or unassociated. ERP local association effects did not significantly differ between control participants and schizophrenia patients. However, in contrast to controls, patients only showed effects of discourse congruence when targets were primed by a word in the local context. When patients had to use discourse context in the absence of local priming, they showed impaired brain responses to the target. Our findings indicate that schizophrenia patients are impaired during discourse comprehension when demands on controlled maintenance of context are high. We further found that ERP measures of increased reliance on local priming predicted reduced social functioning, suggesting that alterations in the neural mechanisms underlying discourse comprehension have functional consequences in the illness.

Semantics, pragmatics, and formal thought disorders in people with schizophrenia

BACKGROUND

The aim of this study was to analyze how formal thought disorders (FTD) affect semantics and pragmatics in patients with schizophrenia.

METHODS

The sample comprised subjects with schizophrenia (n = 102) who met the criteria for the disorder according to the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition Text Revision. In the research process, the following scales were used: Positive and Negative Syndrome Scale (PANSS) for psychopathology measurements; the Scale for the Assessment of Thought, Language, and Communication (TLC) for FTD, Word Accentuation Test (WAT), System for the Behavioral Evaluation of Social Skills (SECHS), the pragmatics section of the Objective Criteria Language Battery (BLOC-SR) and the verbal sections of the Wechsler Adults Intelligence Scale (WAIS) III, for assessment of semantics and pragmatics.

RESULTS

The results in the semantics and pragmatics sections were inferior to the average values obtained in the general population. Our data demonstrated that the more serious the FTD, the worse the performances in the Verbal-WAIS tests (particularly in its vocabulary, similarities, and comprehension sections), SECHS, and BLOC-SR, indicating that FTD affects semantics and pragmatics, although the results of the WAT indicated good premorbid language skills.

CONCLUSION

The principal conclusion we can draw from this study is the evidence that in schizophrenia the superior level of language structure seems to be compromised, and that this level is related to semantics and pragmatics; when there is an alteration in this level, symptoms of FTD appear, with a wide-ranging relationship between both language and FTD. The second conclusion is that the subject's language is affected by the disorder and rules out the possibility of a previous verbal impairment.

Predicting story goodness performance from cognitive measures following traumatic brain injury

PURPOSE

This study examined the prediction of performance on measures of the Story Goodness Index (SGI; Lê, Coelho, Mozeiko, & Grafman, 2011) from executive function (EF) and memory measures following traumatic brain injury (TBI). It was hypothesized that EF and memory measures would significantly predict SGI outcomes.

METHOD

One hundred sixty-seven individuals with TBI participated in the study. Story retellings were analyzed using the SGI protocol. Three cognitive measures--Delis-Kaplan Executive Function System (D-KEFS; Delis, Kaplan, & Kramer, 2001) Sorting Test, Wechsler Memory Scale--Third Edition (WMS-III; Wechsler, 1997) Working Memory Primary Index (WMI), and WMS-III Immediate Memory Primary Index (IMI)--were entered into a multiple linear regression model for each discourse measure. Two sets of regression analyses were performed, the first with the Sorting Test as the first predictor and the second with it as the last.

RESULTS

The first set of regression analyses identified the Sorting Test and IMI as the only significant predictors of performance on measures of the SGI. The second set identified all measures as significant predictors when evaluating each step of the regression function.

CONCLUSION

The cognitive variables predicted performance on the SGI measures, although there were differences in the amount of explained variance. The results (a) suggest that storytelling ability draws on a number of underlying skills and (b) underscore the importance of using discrete cognitive tasks rather than broad cognitive indices to investigate the cognitive substrates of discourse.

Cognitive control and discourse comprehension in schizophrenia

Cognitive deficits across a wide range of domains have been consistently observed in schizophrenia and are linked to poor functional outcome (Green, 1996; Carter, 2006). Language abnormalities are among the most salient and include disorganized speech as well as deficits in comprehension. In this review, we aim to evaluate impairments of language processing in schizophrenia in relation to a domain-general control deficit. We first provide an overview of language comprehension in the healthy human brain, stressing the role of cognitive control processes, especially during discourse comprehension. We then discuss cognitive control deficits in schizophrenia, before turning to evidence suggesting that schizophrenia patients are particularly impaired at processing meaningful discourse as a result of deficits in control functions. We conclude that domain-general control mechanisms are impaired in schizophrenia and that during language comprehension this is most likely to result in difficulties during the processing of discourse-level context, which involves integrating and maintaining multiple levels of meaning. Finally, we predict that language comprehension in schizophrenia patients will be most impaired during discourse processing. We further suggest that discourse comprehension problems in schizophrenia might be mitigated when conflicting information is absent and strong relations amongst individual words are present in the discourse context."There is no "centre of Speech" in the brain any more than there is a faculty of Speech in the mind.The entire brain, more or less, is at work in a man who uses language"William JamesFrom The Principles of Psychology, 1890"The mind in dementia praecox is like an orchestra without a conductor"Kraepelin, 1919.

An automated method to analyze language use in patients with schizophrenia and their first-degree relatives

Communication disturbances are prevalent in schizophrenia, and since it is a heritable illness these are likely present - albeit in a muted form - in the relatives of patients. Given the time-consuming, and often subjective nature of discourse analysis, these deviances are frequently not assayed in large scale studies. Recent work in computational linguistics and statistical-based semantic analysis has shown the potential and power of automated analysis of communication. We present an automated and objective approach to modeling discourse that detects very subtle deviations between probands, their first-degree relatives and unrelated healthy controls. Although these findings should be regarded as preliminary due to the limitations of the data at our disposal, we present a brief analysis of the models that best differentiate these groups in order to illustrate the utility of the method for future explorations of how language components are differentially affected by familial and illness related issues.