HYEEG Discourse in Psychosis: A Neurobehavioural Study

INTRODUCTION

Schizophrenia, often associated with psychosis, is a severe mental disorder that profoundly impacts individuals, families, and society, diminishing quality of life and well-being globally. Disorganized communication-a hallmark feature of schizophrenia-is characterized by impairments in speech production, gesture-speech coordination, and motor behaviours that disrupt the ability to convey and interpret meaning in social contexts. These deficits profoundly undermine interpersonal relationships and social connectedness, creating barriers to meaningful social engagement. The impact of these challenges is particularly acute among marginalized populations, who face additional systemic obstacles such as stigma, reduced access to healthcare, and limited social support networks.

The early onset of psychosis, typically during late adolescence or early adulthood, coincides with a critical developmental period marked by heightened neuroplasticity. Social preferences, communication patterns, and adaptive behaviours are formed during this period. This developmental window is particularly vulnerable to disruptions in social interactions, which can derail neurobehavioural trajectories and contribute to long-term social dysfunction. Understanding how disorganized communication emerges and persists during this critical window is essential for designing early interventions to mitigate its effects.

Social disconnection-the breakdown of interpersonal connectivity and adaptability-is likely rooted in disruptions to the underlying neurobehavioural dynamics that facilitate coordinated interpersonal interactions. These dynamics include synchrony in speech, movement, and neural activity, which are crucial for effective social functioning. Despite significant advancements in mental health research, the specific neural and behavioural underpinnings of disorganized communication remain poorly understood, particularly in their relationship to broader social dysfunction in schizophrenia.

Addressing these challenges requires advanced tools capable of capturing the dynamic and reciprocal processes underlying social interactions. Real-time electroencephalogram (EEG) hyperscanning offers a robust method for studying interbrain synchrony, a critical interpersonal dynamic essential for coordinated social behaviour. This technique allows for the simultaneous recording of brain activity from two individuals engaged in reciprocal sensorimotor interactions, such as cooperative imitation. By analyzing patterns of synchrony and desynchrony in interbrain activity and associated bodily dynamics, EEG hyperscanning provides a detailed framework for examining the mechanisms underlying nonverbal communication and its disruptions.

This study integrates a speech elicitation protocol with standardized transcription methods and natural language processing (NLP) techniques developed by the Diverse International Scientific Consortium for Research in Thought, Language and Communication in Psychosis group. Additionally, it incorporates a validated motor imitation protocol from prior research with healthy participants. By combining EEG hyperscanning data with detailed analyses of verbal and nonverbal behaviours, the study seeks to identify disruptions in cooperative imitation and their links to speech disorganization, providing new insights into the mechanisms of disorganized communication.

This research aims to elucidate the mechanisms underlying disorganized communication by linking neural synchrony to verbal coherence, motor synchrony, and other neurobehavioural responses. These findings aim to inform the development of targeted early interventions that address both the behavioural and neural dimensions of disorganized communication in individuals with psychosis.

RATIONALE

The frontal and temporoparietal brain regions play critical roles in selective attention, inhibitory control, and social cognition. In schizophrenia, disruptions in neural synchronization between these regions-particularly within the alpha (8-12 Hz), beta (13-30 Hz), and gamma (30-100 Hz) frequency bands-are well-documented. Impaired functional connectivity between the prefrontal cortex and temporoparietal regions may contribute to maladaptive, self-focused attention, impairing the processing and integration of external social cues.

Specific dysregulations are hypothesized to underlie these deficits: alpha-band disruptions weaken attentional filtering, beta-band abnormalities impair sustained cognitive control, and gamma-band deficits disrupt the integration of social and perceptual information. These disruptions are expected to create an imbalance between internal and external processing, reducing neural coherence and phase synchronization during social exchanges. This breakdown in neural and behavioural coordination is hypothesized to manifest as neurobehavioural markers of disorganized communication-a hallmark feature of schizophrenia.

SPECIFIC HYPOTHESES

• Impairments in Inhibition-Based Imitation:

Patients with schizophrenia will exhibit significant impairments in inhibition-based imitation compared to automatic imitation, as the former requires higher cognitive control. These impairments are expected to reflect deficits in executive function, particularly the ability to selectively suppress automatic responses.

• Correlation Between Imitation and Speech Disorganization:

Difficulties in inhibition-based imitation will positively correlate with the severity of speech disorganization. Speech disorganization will be measured through clinical evaluations, structured interviews, and natural language processing (NLP) analyses, highlighting shared neural mechanisms underlying executive function and social communication.

• Reduced Interbrain Synchrony:

Interbrain synchrony during interpersonal coordination, assessed using EEG hyperscanning and behavioural analysis, will be significantly reduced in patients compared to healthy controls. This reduction is expected to reflect disruptions in neural oscillations critical for effective social interaction.

MULTIMODAL ANALYSES AND FUTURE DIRECTIONS

This research employs multimodal exploratory analyses to investigate the relationships between interbrain synchrony, bodily activity measures, and conversational speech variables, such as verbal coherence and semantic similarity. These analyses will also explore how these measures relate to symptom severity, providing a comprehensive understanding of their interplay.

By quantifying the effect sizes of these relationships, the study aims to establish foundational evidence for the development of larger-scale research. The results are expected to inform the refinement of experimental protocols, identify robust biomarkers of social dysfunction, and guide the design of targeted early interventions for individuals with psychosis.

Inclusion criteria

• English or French-speaking participants (as dyads matched for language preference).
• Ages 18-60 years.
• Patients meeting the operational criteria for schizophrenia or schizoaffective illness as previously diagnosed by their treating psychiatrist, based on the Diagnostic and Statistical Manual of Mental Disorders (DSM) 5 criteria (Zipursky et al., 2020).
• Patients with less than 5 years of illness onset, based on the time of starting treatment with antipsychotic medication.

Exclusion criteria

• Participants should not have a primary diagnosis of Alcohol or Drug abuse or addiction (however, co-morbid substance abuse with a primary diagnosis of psychotic disorder is not an exclusion criterion).
• Participants should not have a severe medical disorder that would explain psychotic symptoms.
• Participants should not have a past or current history of a primary neurological disorder that can affect speech output
• Participants with IQ below 70 or a concurrent pervasive developmental disorder (e.g., autism) will also be excluded.