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Effects of Brain Stimulation on Higher-Order Cognition

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ClinicalTrials.gov Identifier: NCT03814967
Recruitment Status : Recruiting
First Posted : January 24, 2019
Last Update Posted : June 11, 2019
Sponsor:
Information provided by (Responsible Party):
University of California, Davis

Brief Summary:
The purpose of this study is to better understand the neural correlates of higher-order cognition, both in the healthy brain and in schizophrenia, and to determine how these mechanisms are modulated by transcranial direct current stimulation (tDCS) at frontal and occipital scalp sites. Testing the effects of tDCS at these scalp sites on cognitive task performance will help us understand the roles of the brain regions corresponding to these sites during higher-order cognitive processing (language comprehension, cognitive control, and related attention and memory processes). Behavioral and electrophysiological (EEG) measures will be used to assess cognitive performance. The investigator's overarching hypothesis is that stimulating prefrontal circuits with tDCS can improve cognitive control performance, and ultimately performance on a range of cognitive tasks, as compared to stimulating a different cortical region (occipital cortex) or using sham stimulation. This study is solely intended as basic research in order to understand brain function in healthy individuals and individuals with schizophrenia. This study is not intended to diagnose, cure or treat schizophrenia or any other disease.

Condition or disease Intervention/treatment Phase
Schizophrenia Device: Transcranial Direct Current Stimulation Not Applicable

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 120 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double (Participant, Investigator)
Primary Purpose: Basic Science
Official Title: Transcranial Direct Current Stimulation (tDCS) Studies of Behavioral and Electrophysiological (EEG) Correlates of Higher-Order Cognition
Actual Study Start Date : May 22, 2019
Estimated Primary Completion Date : January 31, 2024
Estimated Study Completion Date : January 31, 2024

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Schizophrenia

Arm Intervention/treatment
Experimental: DLPFC Stimulation
Intervention. 20 minutes of 2 mA direct current stimulation over the dorsolateral prefrontal cortex.
Device: Transcranial Direct Current Stimulation
In tDCS, saline-soaked electrodes are temporary 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). To control for placebo effects, the study will utilize a sham stimulation protocol that consists of very brief constant stimulation (~1 minute). Subjects usually cannot discern the difference between the sham and experimental stimulation protocols due to habituation.

Active Comparator: Occipital Stimulation
Intervention. 20 minutes of 2 mA direct current stimulation over the occipital cortex.
Device: Transcranial Direct Current Stimulation
In tDCS, saline-soaked electrodes are temporary 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). To control for placebo effects, the study will utilize a sham stimulation protocol that consists of very brief constant stimulation (~1 minute). Subjects usually cannot discern the difference between the sham and experimental stimulation protocols due to habituation.

Sham Comparator: Sham Stimulation
Placebo Comparator. 0.5-1 minutes of 2 mA direct current stimulation over the dorsolateral prefrontal cortex followed by 19-19.5 minutes of sham stimulation
Device: Transcranial Direct Current Stimulation
In tDCS, saline-soaked electrodes are temporary 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). To control for placebo effects, the study will utilize a sham stimulation protocol that consists of very brief constant stimulation (~1 minute). Subjects usually cannot discern the difference between the sham and experimental stimulation protocols due to habituation.




Primary Outcome Measures :
  1. EEG Correlates of Language and Cognitive Control [ Time Frame: Assessment will begin immediately following stimulation and last for about 1.5 hours. ]
    Electrophysiological data recorded during completion of cognitive control and language comprehension tasks. We will measure oscillatory activity in the theta, alpha, beta and gamma frequency bands.

  2. Behavioral Response (Cognitive Control Task) [ Time Frame: Assessment will begin immediately following stimulation and last for about 1.5 hours. ]
    We will assess performance on the Dot Pattern Expectancy (DPX) task (error rates and d-prime scores).

  3. Behavioral Response (Language Task) [ Time Frame: Assessment will begin immediately following stimulation and last for about 1.5 hours. ]
    We will assess performance on a novel Language Comprehension task (accuracy and semantic relatedness judgement scores).



Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 35 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

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.

Inclusion Criteria for Patients with Schizophrenia Only:

  • Diagnosis of schizophrenia, schizophreniform or schizoaffective disorder
  • No medication changes in the prior month
  • No medication changes anticipated in the upcoming month
  • Stable outpatient or partial hospital status
  • Normal IQ (>70; IQ will be measured by administering the Wechsler Abbreviated Scale of Intelligence (WASI) test)
  • Must not be currently taking the antipsychotic clozapine

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

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03814967


Contacts
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Contact: Megan A Boudewyn, Ph.D. (916) 734-4149 maboudewyn@ucdavis.edu

Locations
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United States, California
Imaging Research Center Recruiting
Sacramento, California, United States, 95817
Contact: Vanessa Zarubin, BS/BA    916-734-3749    vczarubin@ucdavis.edu   
Principal Investigator: Cameron Carter, M.D.         
Sponsors and Collaborators
University of California, Davis

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Responsible Party: University of California, Davis
ClinicalTrials.gov Identifier: NCT03814967     History of Changes
Other Study ID Numbers: 1344169
First Posted: January 24, 2019    Key Record Dates
Last Update Posted: June 11, 2019
Last Verified: June 2019
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Yes
Plan Description: Select data from this study may be submitted to the National Institute of Mental Health Data Archive (NDA). NDA is a data repository run by the National Institute of Mental Health (NIMH) that allows researchers studying mental illness to collect and share de-identified information with each other. The data repository is accessible only to qualified investigators. All subject data will be de-identified (subject names will not be used) and each subject will have a separate identifier called a Global Unique Identifier (GUID) to remove any possibility that "the identities of the subjects cannot be readily ascertained or otherwise associated with the data by the repository staff or secondary data users." (45 CFR, 46.102).

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: Yes
Device Product Not Approved or Cleared by U.S. FDA: Yes
Pediatric Postmarket Surveillance of a Device Product: No
Product Manufactured in and Exported from the U.S.: No
Keywords provided by University of California, Davis:
schizophrenia
EEG
tDCS
dorsolateral prefrontal cortex
cognitive control
language
transcranial direct current stimulation
Additional relevant MeSH terms:
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Schizophrenia
Schizophrenia Spectrum and Other Psychotic Disorders
Mental Disorders