Brain Stimulation, Clinical Symptoms and Cognition

Study Overview
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Brief Summary
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The purpose of this study is to test the impact of non-invasive brain stimulation, transcranial direct current stimulation (tDCS), on auditory hallucinations, negative symptoms and cognition in schizophrenia. Clinical measures will be used to assess clinical symptoms and cognitive performance to test the hypothesis that a course of tDCS can reduce auditory hallucinations and negative symptoms in schizophrenia.

Official Title
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Transcranial Direct Current Stimulation (tDCS) Studies of Auditory Hallucinations, Negative Symptoms and Cognition in Schizophrenia

Conditions
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Schizophrenia

Intervention / Treatment
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* Device: Transcranial Direct Current Stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Participants must be able to sufficiently speak and understand English so as to be able to understand and complete cognitive tasks. All subjects must have the ability to give valid informed consent. No children under the age of 18 will be recruited. Diagnosis of schizophrenia, schizophreniform, or schizoaffective disorder Stable outpatient or partial hospital status Normal IQ (>70; IQ will be measured by administering the Wechsler Abbreviated Scale of Intelligence (WASI) test) Exclusion Criteria: Pacemakers Implanted electrical (brain and spinal) stimulators Implanted defibrillator Metallic implants Skin damage or skin conditions such as eczema at the sites where electrodes will be placed Hair styles hindering the placement of electrodes Cranial pathologies Head trauma Epilepsy Mental retardation Any known history of neurological disorders (including epilepsy, amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), stroke, cerebral palsy, any DSM-5 axis I psychiatric disorder (for healthy control subjects), autism) Uncorrected vision problems that would hinder cognitive testing (this also pertains to subjects with color blindness in tasks where discriminating colored objects/items is necessary for successful performance) Pregnancy Substance dependence in the past six months Substance abuse in the past month

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 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: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: dlPFC/TPJ Stimulation + Rest<br>20 minutes of 2 mA direct current stimulation during rest. | Device: Transcranial Direct Current Stimulation<br>* In tDCS, saline-soaked electrodes are temporarily affixed to the scalp and connected to a battery-powered current generator. A weak (2 mA) constant current is then briefly applied (20 minutes) to stimulate the targeted brain area (e.g. the DLPFC, TPJ, Occipital Cortex) depending on the phase of the study.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Symptom Severity of Auditory Hallucinations | Participants will undergo diagnostic (clinical) interviews to rate their symptom severity using measures including, but not limited to, the Brief Psychiatric Rating Scale (rated 1-7, with a high rating indicating more severe symptoms), the Scale of the Assessment of Positive Symptoms (rated 0-5, with a high rating indicating more severe symptoms), and the Scale for the Assessment or Negative Symptoms (rated 0-5, with a high rating indicating more severe symptoms). | Assessment begins with the initial baseline interview and concludes after a 2-week follow-up assessment using the same clinical measures. | 
| Change in Symptom Severity of Negative Symptoms | Participants will undergo diagnostic (clinical) interviews to rate their symptom severity using measures including, but not limited to, the Brief Psychiatric Rating Scale (rated 1-7, with a high rating indicating more severe symptoms), the Scale of the Assessment of Positive Symptoms (rated 0-5, with a high rating indicating more severe symptoms), and the Scale for the Assessment or Negative Symptoms (rated 0-5, with a high rating indicating more severe symptoms). | Assessment begins with the initial baseline interview and concludes after a 2-week follow-up assessment using the same clinical measures. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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EEG, schizophrenia, tDCS, dorsolateral prefrontal cortex, temporoparietal junction, cognitive control, auditory hallucinations, transcranial direct current stimulation