Neurostimulation-enhanced Behavioral Remediation of Social Cognition in Schizophrenia

Study Overview
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Brief Summary
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Social cognition concerns the understanding of how people think about others and how that, in turn, influences our behavior, feelings, and social interactions. schizophrenia social-cognitive impairment is profound (effect size D>1.2), medication resistant and critically limits functional well-being . Social cognition involves complex patterns of coordinated activity within numerous cortical and subcortical networks, making it a difficult target for clinical neuroscience investigation. Yet, prior research demonstrates that sensory-perceptual dysfunction in schizophrenia can upwardly generalize into higher-order social-cognitive impairment making perception a tractable and fruitful approach for studying social cognition in schizophrenia. Here, the investigators explore how distortions in perception of temporal coincidence can contribute to the aberrant inferences of physical causation and social agency.

Detailed Description
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Social cognitive deficits in these patients are robust and hinder their ability to maintain gainful employment as well as forge and sustain meaningful social relationships. Current antipsychotic medications are largely ineffective in treating these symptoms. The proposed protocol aims at utilizing Noninvasive Brain Stimulation (NIBS) and cognitive behavioral training to enhance core perceptual impairment in marking time that may contribute to both social and nonsocial cognitive dysfunction in schizophrenia. Cognitive behavioral training along the line investigators propose has no reported adverse effects.The transdirect current stimulation (tDCS) is a very safe method with encouraging results in previous works in which no severe adverse events where found. There are a few minor side effects including skin irritation, a phosphene at the start of stimulation, nausea, headache, dizziness, and itching under the electrode. A recent study of over 500 subjects using the currently accepted protocol reported only a slight skin irritation and a phosphene as side effects. Patients can benefit from a significant improvement of invalidant symptoms but also of their quality of life. To ensure safety, patients will be accompanied throughout the protocol by professionals trained in the management of their disease. Besides the protocol procedure, patients will be supported, in all centers, according to the international recommendations in terms of safety and practice. Patients receiving placebo procedure after randomization will pursue pharmacological treatment and usual health care.

Official Title
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Neurostimulation-enhanced Behavioral Remediation of Social Cognition in Schizophrenia

Conditions
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Behaviors and Mental Disorders

Intervention / Treatment
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* Device: transcranial Direct Current Stimulation tDCS


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: be between 18 and 45-years-old have normal hearing assessed by the Five-minute hearing test have French as a first language be able to provide written informed consent be right handed as measured by the Edinburgh handedness scale covered by, or having the right to Social Security informed consent signed patients with diagnosis of schizoprenia or schizoaffective disorder-depressive type as determined by the SCID Diagnostic Interview for DSM-V and administered by a clinician clinically stable and on a stable medication regiment for the past 3 months Exclusion Criteria: significant medical or neurological illness or history of fetal alcohol exposure that may increase risks of the study, significantly affect brain function, or impede participation substance dependence (except nicotine) or abuse not in remission within the past six months or recent use presenting the possibility of acute intoxication or withdrawal a history of any Axis I psychiatric disorder except those required in the inclusion criteria, any history of pervasive developmental disorder or mental retardation for Visit 3: If participating in tCDS Contraindications for tDCS (pacemaker or brain stimulator) and/or MRI (neurologic stimulator, pacemaker, cardiac defibrillator, cardiac prosthesis, vascular prosthesis, intracranial clips or clamps, cerebrospinal fluid derivation, metallic splinters in the eyes) patients under curatorship/guardianship and whose clinical condition requires inpatient procedure under constraint healthy controls must not be currently using psychoactive médications or have a first-degree relative with a psychotic disorder

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: The investigators will enroll 150 subjects comprising three population groups SZ, At Risk and HS.) Immediately after inclusion, participants will be randomized into 2 equal groups via random generation of two binary integer's reflecting tDCS-treatment condition or the tDCS control (sham) resulting in random allocation into one of 2 study arms. This randomization will be stratified per population group to insure that both conditions are equally reflected across all three groups.
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: transcranial Direct Current Stimulation ( tDCS )<br>Intensity : 1,5mA Duration : 20 minutes stimulation over frontal (F3/F4) electrodes | Device: transcranial Direct Current Stimulation tDCS<br>* 75 participants will receive 20 minutes of active tDCS (1,5mA, 20 minutes stimulation over frontal (F3/F4) electrodes ); A group of 75 participants will receive 1,5mA 20 minutes of stimulation over parietal (CP3 CP4) electrodes. During this stimulation session and we will also measure your ability to perceive visual and auditory objects presented by a computer, while recording your brain activity using electroencephalography or EEG (a technique using electrodes that measures the electrical activity of your brain)<br>|
| Sham Comparator: transcranial Direct Current Stimulation ( tDCS)<br>Intensity : 1,5mA Duration : 20 minutes stimulation over parietal(CP3 CP4) electrodes | Device: transcranial Direct Current Stimulation tDCS<br>* 75 participants will receive 20 minutes of active tDCS (1,5mA, 20 minutes stimulation over frontal (F3/F4) electrodes ); A group of 75 participants will receive 1,5mA 20 minutes of stimulation over parietal (CP3 CP4) electrodes. During this stimulation session and we will also measure your ability to perceive visual and auditory objects presented by a computer, while recording your brain activity using electroencephalography or EEG (a technique using electrodes that measures the electrical activity of your brain)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Causation Task - testing time based causal judgments | Primary metric: threshold defined as the smallest time difference (in 16.7ms increments) at which subject judge ball movement B to be caused by the impact of ball A 75% of the time. | 3 months | 
| Triangle Task - measuring the extent to which temporal coincidence is used to infer causality in a social situation | Primary metric: threshold of tolerated relational time delay (levels in 16.7ms increments) between interacting visual figures (i.e triangles), under which participants reliably (at 75%) perceive social agency or social interactions. | 3 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| EEG Task 1, Time visual oddball task - for measuring electrophysiological markers of active temporal (time) deviance detection | Primary metric: Mismatch negativity in the event related potentials of electrodes over the visual cortex with typical latency of 150-250ms after the onset of the deviant stimuli | 3 months | 
| EEG Task 2, Covert visual simultaneity task - an exploratory task designed to model the visual Simultaneity behavioral task | Primary metric: Dependent measure: decibel change in Alpha and Beta power across bellow- threshold and above- threshold conditions | 3 months | 
| Resting state oscillatory structure | Primary metric: Dependent measure: decibel change in Alpha and Beta power during rest | 3 months |