Sustained attention ability in schizophrenia: Investigation of conflict monitoring mechanisms

Feuerstein Instrumental Enrichment Program for People With Schizophrenia After the First Episode of Psychosis: Protocol for an Open-Label Intervention Study

BACKGROUND

Schizophrenia is a disorder associated with neurocognitive deficits that adversely affect daily functioning and impose an economic burden. Cognitive rehabilitation interventions, particularly during the early phases of illness, have been shown to improve cognition, functionality, and quality of life. The Feuerstein Instrumental Enrichment (FIE) program, based on the Mediated Learning Experience and the Structural Cognitive Modifiability theory, has been applied in various disorders, but its applicability in schizophrenia has not yet been clarified.

OBJECTIVE

This study aims to investigate the effects of the FIE program on the functionality of patients with first-episode schizophrenia.

METHODS

In total, 17 patients will be recruited for an open-label intervention consisting of twice-weekly sessions for 10 weeks. The primary outcome measure will be changes in the Goal Achievement Scale score. Maze task performance from the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) battery will serve as a secondary outcome measure. At the same time, changes in Positive and Negative Syndrome Scale scores and other MATRICS domains will be analyzed as exploratory outcomes. Assessments will be administered before and after the intervention, with a follow-up period of 6 months.

RESULTS

This trial was preregistered in The Brazilian Registry of Clinical Trials (RBR-4gzhy4s). By February 2024, 11 participants were enrolled in the training. Recruitment is expected to be completed by May 2024. Data analysis will be conducted between May and September 2024. The results are expected to be published in January 2025.

CONCLUSIONS

This study may establish a protocol for the FIE program that uses mediation techniques for individuals in the early stages of schizophrenia. The results will add to the knowledge about strategies to promote cognitive skills and functional impairment in daily life.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/57031.

Modulation of hemispheric asymmetry in executive control of attention in schizophrenia with atypical antipsychotic treatment: Potential benefits of olanzapine

Deficits in executive control of attention have been reported in schizophrenia patients, but can be ameliorated by treatment of atypical antipsychotics along with the symptoms. However, it remains unclear whether this effect is related to a modulation of hemispheric asymmetry in executive control by the medicine. In this behavioral study, we employed a lateralized version of the attention network test to examine the hemispheric asymmetry of executive control in schizophrenia patients before and after olanzapine treatment, compared to matched healthy controls. Executive control was measured as a conflict effect, indexed as the response time (RT) difference between incongruent versus congruent flanker conditions, and was compared between stimuli presented in the left and the right visual field (i.e., processed by right versus left hemisphere of the brain). Results showed that pre-treatment schizophrenia patients revealed a right hemisphere superiority in conflict effect (i.e., a smaller effect in the right hemisphere than in the left hemisphere), driven by the incongruent condition. Olanzapine treatment reduced this right hemisphere superiority by improving the efficiency of the left hemisphere in the incongruent condition. These results suggested that olanzapine treatment may improve the efficiency of executive control in the left hemisphere in schizophrenia patients.

N2 Responses in Youths With Psychosis Risk Syndrome and Their Association With Clinical Outcomes: A Cohort Follow-Up Study Based on the Three-Stimulus Visual Oddball Paradigm

OBJECTIVE

Schizophrenia often occurs during youth, and psychosis risk syndrome occurs before the onset of psychosis. The aim of this study was to determine whether the visual event-related potential responses in youths with psychosis risk syndrome were defective in the presence of interference stimuli and associated with their clinical outcomes.

METHODS

A total of 223 participants, including 122 patients with psychosis risk syndrome, 50 patients with emotional disorders, and 51 healthy control subjects, were assessed. Baseline EEG was recorded during the three-stimulus visual oddball task. The event-related potentials induced by square pictures with different colors were measured. Almost all patients with psychosis risk syndrome were followed up for 12 months and were reclassified into three subgroups: conversion, symptomatic, and remission. The differences in baseline event-related potential responses were compared among the clinical outcome subgroups.

RESULTS

The average N2 amplitude of the psychosis risk syndrome group was significantly less negative than that in the healthy control group (d=0.53). The baseline average N2 amplitude in the conversion subgroup was significantly less negative than that in the symptomatic (d=0.58) and remission (d=0.50) subgroups and in the healthy control group (d=0.97). The average N2 amplitude did not differ significantly between the symptomatic and remission subgroups (d=0.02). However, it was significantly less negative in the symptomatic and remission subgroups than in the healthy control group (d=0.46 and d=0.38). No statistically significant results were found in the P3 response.

CONCLUSIONS

Youths with psychosis risk syndrome had significant N2 amplitude defects in attention processing with interference stimuli. N2 amplitude shows potential as a prognostic biomarker of clinical outcome in the psychosis risk syndrome.

Application of Machine Learning to Diagnostics of Schizophrenia Patients Based on Event-Related Potentials

Schizophrenia is a major psychiatric disorder that significantly reduces the quality of life. Early treatment is extremely important in order to mitigate the long-term negative effects. In this paper, a machine learning based diagnostics of schizophrenia was designed. Classification models were applied to the event-related potentials (ERPs) of patients and healthy subjects performing the visual cued Go/NoGo task. The sample consisted of 200 adult individuals ranging in age from 18 to 50 years. In order to apply the machine learning models, various features were extracted from the ERPs. The process of feature extraction was parametrized through a special procedure and the parameters of this procedure were selected through a grid-search technique along with the model hyperparameters. Feature extraction was followed by sequential feature selection transformation in order to prevent overfitting and reduce the computational complexity. Various models were trained on the resulting feature set. The best model was support vector machines with a sensitivity and specificity of 91% and 90.8%, respectively.

Test–retest reliability and criterion-related validity of Shih–Hsu test of attention between people with and without schizophrenia

Introduction

The “Shih–Hsu Test of Attention” (SHTA) is an iPad-based attention assessment tool developed in recent years by occupational therapists and has acceptable criterion-related validity and high test–retest reliability in preliminary application. This research project explores the criterion-related validity and test–retest reliability of SHTA between people with and without schizophrenia.

Method

The participants were 76 adults with schizophrenia aged 20–64 years, and 66 adults without diagnosed mental illness aged 20–64 years were recruited in this study on a voluntary basis. Each participant was assessed twice. The participants completed both the SHTA and Chu’s Attention Test (CAT) in the first test and the SHTA after 3 weeks.

Findings

Analytical results indicate that the SHTA has satisfactory test–retest reliability (ICC = 0.67) and criterion-related validity (γ = 0.29, p < 0.05*) for adults with schizophrenia and has high test–retest reliability (ICC = 0.90) and criterion-related validity (γ = 0.25, p < 0.05*) for adults without diagnosed mental illness. The MDC% value for the subjects without diagnosed mental illness was 12.1%, indicating acceptable random measurement error.

Conclusion

Our preliminary findings show that the iPad-based attention assessment tool, SHTA, has satisfactory criterion-related validity and test–retest reliability, supporting the future application of SHTA as an attention assessment tool.

Latent ERP components of cognitive dysfunctions in ADHD and schizophrenia

OBJECTIVE

The main goal was to assess common and specific deficits of cognitive control in (Attention Deficit Hyperactivity Disorder) ADHD and schizophrenia (SZ) using event-related potentials (ERPs).

METHOD

Behavioral and EEG data in cued GO/NOGO task were recorded in 132 healthy controls (HC) and age, gender and education matched 63 ADHD adults, and 68 SZ patients.

RESULTS

N2d wave in NOGO-GO contrast of ERPs did not differ between the groups while the P3d wave discriminated SZ group from two other groups. Latent components of ERPs were extracted by blind source separation method based on second-order statistics Kropotov et al. (2017) and compared between the groups. A counterpart of N2d wave of a frontally distributed latent component was smaller in SZ indicating a specific frontal dysfunction of conflict detection in SZ. Two centrally distributed P3 sub-components were reduced in both groups indicating a non-specific dysfunction of action inhibition operations in ADHD and SZ.

CONCLUSION

A pattern of specific and common dysfunctions in terms of latent ERP components shows a more complex picture of functional impairment in schizophrenia and ADHD in comparison to conventional N2/P3 ERP description.

SIGNIFICANCE

The latent component approach shows a functionally different pattern of cognitive control impairment in comparison to the conventional ERP analysis.

Visual expertise for print in schizophrenia: Analysis of the N170 component

Reading deficits have been reported for patients suffering from schizophrenia namely, specific phonological processing deficits. Phonological processing skills are crucial in the learning-to-read process as they are necessary to develop visual expertise for print, which reflects the neural specialization for print. The present study is the first to test visual expertise for print in patients suffering from schizophrenia by measuring the N170 component. Patients and pair-matched healthy control participants performed a lexical decision task, in which words and symbols were presented. As expected, larger N170 amplitudes to word than to control stimuli were observed at the left occipito-temporal site PO7 but not at the PO8. More importantly, the modulation of the N170 as a function of the stimulus and hemisphere did not vary between patients and controls. This result suggests preserved visual expertise for print processing in patients suffering from schizophrenia.

Sustaining attention to simple visual tasks: a central deficit in schizophrenia? A systematic review

Impairments in sustained attention, that is, the ability to achieve and maintain the focus of cognitive activity on a given stimulation source or task, have been described as central to schizophrenia. Today, sustained attention deficit is still considered as a hallmark of schizophrenia. Nevertheless, current findings on this topic are not consistent. To clarify these findings, we attempt to put these results into perspective according to the type of assessment (i.e., overall and over time assessment), the participants' characteristics (i.e., clinical and demographic characteristics), and the paradigms (i.e., traditionally formatted tasks, go/no-go tasks, and the sustained attention task) and measures used. Two types of assessment lead to opposite findings; they do not evaluate sustained attention the same way. Studies using overall assessments of sustained attention ability tend to reveal a deficit, whereas studies using over time assessments do not. Therefore, further research is needed to investigate the underlying cognitive control mechanisms of changes in sustained attention in schizophrenia.