Examining Neural Connectivity in Schizophrenia Using Task-Based EEG: A Graph Theory Approach

Schizophrenia (SZ) is a complex disorder characterized by a range of symptoms and behaviors that have significant consequences for individuals, families, and society in general. Electroencephalography (EEG) is a valuable tool for understanding the neural dynamics and functional abnormalities associated with schizophrenia. Research studies utilizing EEG have identified specific patterns of brain activity in individuals diagnosed with schizophrenia that may reflect disturbances in neural synchronization and information processing in cortical circuits. Considering the temporal dynamics of functional connectivity provides a more comprehensive understanding of brain networks' organization and how they change during different cognitive states. This temporal perspective would enhance our understanding of the underlying mechanisms of schizophrenia. In the present study, we will use measures based on graph theory to obtain dynamic and static indicators in order to evaluate differences in the functional connectivity of individuals diagnosed with SZ and healthy controls using an ecologically valid task. At the static level, patients showed alterations in their ability to segregate information, particularly in the default mode network (DMN). As for dynamic measures, patients showed reduced values in most metrics (segregation, integration, centrality, and resilience), reflecting a reduced number of dynamic states of brain networks. Our results show the utility of combining static and dynamic indicators of functional connectivity from EEG sensors.

Metacognition in schizophrenia: A practical overview of psychometric metacognition assessment tools for researchers and clinicians

Metacognition refers to the cognitive ability to control, monitor and modulate cognitive processes thus guiding and orienting behavior: a continuum of mental activities that ranges from more discrete ones, such as the awareness of the accuracy of others' judgment, to more integrated activities, such as the knowledge of cognitive processes. Metacognition impairment in schizophrenia, which is considered a core feature of the illness, has become a growing research field focusing on a wide range of processes including reasoning, autobiographical memory, memory biases, cognitive beliefs and clinical insight. There is a well-established relationship between metacognition and schizophrenia symptoms severity, as well as between impaired metacognitive functioning and specific symptomatic sub-domains, such as positive symptoms, negative symptoms, or disorganization. The development of specific cognitive-derived psychotherapies for metacognitive deficits in schizophrenia has been ongoing in the last years. Although sharing a metacognitive feature, these treatments focus on different aspects: false or unhelpful beliefs for metacognitive therapy; cognitive biases for metacognitive training; schematic dysfunctional beliefs for cognitive behavioral therapy (CBT) for psychoses; metacognitive knowledge and sense of identity for MERIT; interpersonal ideas or events triggering delusional thinking for MIT-P. This article reviews the instruments designed to assess metacognitive domains and functions in individuals with schizophrenia, providing mental health professionals with an overview of the heterogeneous current scenario ranging from self-administered scales to semi-structured interviews, which are supported by a variety of theoretical frameworks. Future directions may address the need for more specific and refined tools, also able to follow-up psychotherapeutic-induced improvements.

Unveiling the Associations between EEG Indices and Cognitive Deficits in Schizophrenia-Spectrum Disorders: A Systematic Review

Cognitive dysfunctions represent a core feature of schizophrenia-spectrum disorders due to their presence throughout different illness stages and their impact on functioning. Abnormalities in electrophysiology (EEG) measures are highly related to these impairments, but the use of EEG indices in clinical practice is still limited. A systematic review of articles using Pubmed, Scopus and PsychINFO was undertaken in November 2021 to provide an overview of the relationships between EEG indices and cognitive impairment in schizophrenia-spectrum disorders. Out of 2433 screened records, 135 studies were included in a qualitative review. Although the results were heterogeneous, some significant correlations were identified. In particular, abnormalities in alpha, theta and gamma activity, as well as in MMN and P300, were associated with impairments in cognitive domains such as attention, working memory, visual and verbal learning and executive functioning during at-risk mental states, early and chronic stages of schizophrenia-spectrum disorders. The review suggests that machine learning approaches together with a careful selection of validated EEG and cognitive indices and characterization of clinical phenotypes might contribute to increase the use of EEG-based measures in clinical settings.

[Metacognition as a pathway to the study and treatment of fragmentation in schizophrenia]

This paper explores the potential of recent research on metacognition to offer new avenues to assess and address the phenomenon of fragmentation in schizophrenia, which was described by E.Bleuler as «splitting». The concepts of metacognition characterize and quantify alterations or decrements in the processes by which fragments or pieces of information are integrated into a coherent sense of self and others. A method for assessing metacognition is presented along with research examining the presence and importance of metacognitive deficits in schizophrenia. Greater levels of metacognitive deficits have been detected in different phases of schizophrenia and linked to poorer psychosocial outcomes. These data were obtained both in foreign and preliminary Russian studies. The authors suggest that treatments, which successfully target metacognitive capacity, may uniquely promote wellness and recovery in schizophrenia.

Relationship of Metacognition and Insight to Neural Synchronization and Cognitive Function in Early Phase Psychosis

Metacognition is the process of thinking about one's own mental states. It involves a range of faculties that allow an individual to integrate information and form understanding of self and others, and use this understanding to respond to life challenges. Clinical insight is the awareness of one's mental illness, its consequences, and the need for treatment. Persons with psychotic disorders show impaired metacognition and insight, but the neurobiological bases for these impairments are not well characterized. We hypothesized that metacognition and insight may depend on capacity of neural circuits to synchronize at gamma frequencies, as well as the integrity of underlying cognitive processes. In order to test these hypotheses, 17 adults with early phase psychosis were evaluated. Metacognition was assessed with the Metacognition Assessment Scale-Abbreviated, and insight was assessed with the Scale of Unawareness of Illness-Abbreviated. The auditory steady state response (ASSR) to gamma range stimulation (40 Hz) was used as an index of neural synchronization. Cognitive function was assessed using the Brief Assessment of Cognition in Schizophrenia. Increases in ASSR power were associated with poorer metacognition and insight. Higher cognitive performance was associated with higher levels of metacognitive function and insight. These findings suggest that altered neural synchronization and constituent cognitive processes affect both metacognition and insight in early phase psychosis and may offer targets for both pharmacological and psychotherapeutic interventions.

Metacognitive function and fragmentation in schizophrenia: Relationship to cognition, self-experience and developing treatments

Bleuler suggested that fragmentation of thought, emotion and volition were the unifying feature of the disorders he termed schizophrenia. In this paper we review research seeking to measure some of the aspects of fragmentation related to the experience of the self and others described by Bleuler. We focus on work which uses the concept of metacognition to characterize and quantify alterations or decrements in the processes by which fragments or pieces of information are integrated into a coherent sense of self and others. We describe the rationale and support for one method for quantifying metacognition and its potential to study the fragmentation of a person's sense of themselves, others and the relative place of themselves and others in the larger human community. We summarize research using that method which suggests that deficits in metacognition commonly occur in schizophrenia and are related to basic neurobiological indices of brain functioning. We also present findings indicating that the capacity for metacognition in schizophrenia is positively related to a broad range of aspects of psychological and social functioning when measured concurrently and prospectively. Finally, we discuss the evolution and study of one therapy that targets metacognitive capacity, Metacognitive Reflection and Insight Therapy (MERIT) and its potential to treat fragmentation and promote recovery.