Cognitive coordination and its neurobiological bases: A new continent to explore

Qualitative Differences in Attribution of Mental States to Other People in Autism and Schizophrenia: What are the Tools for Differential Diagnosis?

The differential diagnosis between schizophrenia spectrum disorders (SSD) and autism spectrum disorders (ASD) remains an important clinical question, because they have overlap in clinical diagnosis. This study explored the differences between ASD (n = 44) and SSD patients (n = 59), compared to typically developing peers (n = 63), in completing an advanced Theory of Mind (ToM) task. The outcome found several differences between groups. The SSD patients showed greater difficulty in understanding social scenarios, while ASD individuals understood the stories, but did not correctly identify the protagonist's intention. The interesting aspect of the results is that some ToM stories are more informative about the mentalistic reasoning of the two clinical groups, namely, the stories that investigate pretend, persuasion, double bluff and ironic joke constructs.

Perceptual grouping in disorganized schizophrenia

This study evaluated visual perceptual grouping in schizophrenia to test the hypothesis that the disorganization syndrome in schizophrenia is related to a deficit in cognitive coordination. Perceptual grouping was examined with three psychophysically well-controlled tasks in patients with disorganized schizophrenia (n=11), non-disorganized schizophrenia (n=24), psychotic disorders other than schizophrenia (n=31) and non-psychotic psychiatric disorders (n=35). These measures assessed processing of both concurrent and preceding stimulus context. Deficits in perceptual grouping were observed on all three tasks in disorganized schizophrenia patients. Dysfunctional perceptual grouping mechanisms produced both enhanced and impaired task performance suggesting that the pattern of performance observed was the result of a specific deficit in the grouping of stimulus elements. We interpret these data as further support for the hypothesis that the disorganization syndrome in schizophrenia reflects a widespread deficit in the cognitive coordination of contextually related stimuli, leading to dysfunctional grouping of stimulus features in vision, thought and language.

Theory of mind and perceptual context-processing in schizophrenia

INTRODUCTION

A series of studies have suggested that schizophrenia patients are deficient in theory of mind (ToM). However, the cognitive mechanisms underlying ToM deficits in schizophrenia are largely unknown. The present study examined the hypothesis that impaired ToM in schizophrenia can be understood as a deficit in context processing.

METHODS

Disorganised schizophrenia patients (N = 12), nondisorganised schizophrenia patients (N = 36), and nonpsychotic psychiatric patients (N = 26) were tested on three ToM tasks and a visual size perception task, a measure of perceptual context processing. In addition, statistical analyses were carried out which compared chronic, treatment-refractory schizophrenia patients (N = 28) to those with an episodic course of illness (N = 20).

RESULTS

Overall, ToM performance was linked to deficits in context processing in schizophrenia patients. Statistical comparisons showed that disorganised as well as chronic schizophrenia patients were more impaired in ToM but more accurate in a visual size perception task where perceptual context is misleading.

CONCLUSIONS

This pattern of results is interpreted as indicating a possible link between deficits in ToM and perceptual context processing, which together with deficits in perceptual grouping, are part of a broader dysfunction in cognitive coordination in schizophrenia.