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.