Transcranial Direct Current Stimulation (tDCS) and Cognitive Processing

Study Overview
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Brief Summary
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This research is being done to determine whether transcranial direct current stimulation (tDCS) can improve certain mental abilities. In this research, battery powered device is used to deliver very weak electrical current to the surface of the scalp while participants complete cognitive tasks. Our aim is to find out whether tDCS will improve task performance in both healthy adults and those with neurological impairment.

Detailed Description
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Participants enrolled into this study may be asked to do the following: Grant permission for the researchers to view medical records associated with their language/cognitive difficulties (if applicable. Complete a questionnaire, provide a health history, and take some pencil-and-paper tests of problem-solving and memory in order to verify eligibility to participate and to able to safely undergo the experimental procedures. Complete several tasks (i.e., saying words out loud, naming objects, drawing designs, remembering lists of words, searching for images or letters, and/or completing puzzles) based upon a number of cognitive functions such as language, memory, vision, processing, and perception. Wear electrodes that will be placed on the scalp with a large rubberized band. These electrodes will administer very weak electrical current (tDCS) from a battery powered device for 20 to 60 minutes. Participation in several study conditions. The exact conditions and their order will be randomized. Under some conditions, participants may receive active stimulation (tDCS) and under other conditions, they may receive sham stimulation. The experimental sessions will last approximately 2 hours and participants may be asked to have more than one testing session in a day or to return for additional sessions. Have a Magnetic Resonance Imaging (MRI) brain scan.

Official Title
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Transcranial Direct Current Stimulation (tDCS)and Cognitive Processing

Conditions
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Aphasia, Autism, Schizophrenia

Intervention / Treatment
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* Procedure: Transcranial Direct Current Stimulation (tDCS)


Participation Criteria
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Eligibility Criteria
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Eligibility Criteria by Study Group Normal Controls Inclusion Criteria: Right handed (as determined by the Edinburgh battery) English as native language Normal Controls Exclusion Criteria: Appreciable deficits in hearing Appreciable problems with articulation Schizophrenia, bipolar disorder, or major depression Appreciable accent Any neurological disorder associated with cognitive impairment or neuroanatomic abnormality Language-based learning disorder Any implanted metal device (precludes use of tDCS) Any implanted cardiac pacemaker Dementia or Mini-Mental State Exam < 24 Estimated verbal intelligence < 70 Aphasia Group Inclusion Criteria: Right handed (as determined by the Edinburgh battery) English as native language History of acquired left-hemisphere dysfunction Aphasia Group Exclusion Criteria: Appreciable deficits in hearing Schizophrenia, bipolar disorder, or major depression Appreciable accent Language-based learning disorder Any implanted metal device Any implanted cardiac pacemaker Mini-Mental State Exam < 21/27 (omitting naming & items) Estimated verbal intelligence < 70 Schizophrenia/First-degree Family Members Inclusion Criteria: Right handed (as determined by the Edinburgh battery) English as native language Diagnosis of schizophrenia (SZ) or bipolar disorder (BD) First degree family member of individual with SZ or BD Schizophrenia/First-degree Family Members Exclusion Criteria: Appreciable deficits in hearing Appreciable accent Any implanted metal device (precludes use of tDCS) Any implanted cardiac pacemaker Dementia or Mini-Mental State Exam < 24 Estimated verbal intelligence < 70 High-functioning Autism Inclusion Criteria: Right handed (as determined by the Edinburgh battery) English as native language Diagnosis of High-functioning autism (i.e., Asperger's) High-functioning Autism Exclusion Criteria: Appreciable deficits in hearing Schizophrenia, bipolar disorder, or major depression Appreciable accent Any implanted metal device Any implanted cardiac pacemaker Dementia or Mini-Mental State Exam < 24 Estimated verbal intelligence < 70

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 79 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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Controls<br>Healthy Controls with no known cognitive impairment will have Transcranial Direct Current Stimulation (tDCS) administered and receive either Anodal, Cathodal or Sham tDCS. | Procedure: Transcranial Direct Current Stimulation (tDCS)<br>* Anodal, Cathodal or Sham tDCS.<br>|
| Individuals with schizophrenia<br>Individuals with schizophrenia and first-degree relatives will have Transcranial Direct Current Stimulation (tDCS) administered and receive either Anodal, Cathodal or Sham tDCS. | Procedure: Transcranial Direct Current Stimulation (tDCS)<br>* Anodal, Cathodal or Sham tDCS.<br>|
| Individuals with aphasia<br>Individuals with aphasia will have Transcranial Direct Current Stimulation (tDCS) administered and receive either Anodal, Cathodal or Sham tDCS. | Procedure: Transcranial Direct Current Stimulation (tDCS)<br>* Anodal, Cathodal or Sham tDCS.<br>|
| Individuals with high-functioning autism<br>Individuals with high-functioning autism will have Transcranial Direct Current Stimulation (tDCS) administered and receive either Anodal, Cathodal or Sham tDCS. | Procedure: Transcranial Direct Current Stimulation (tDCS)<br>* Anodal, Cathodal or Sham tDCS.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Indices of cognitive function |  | The average time frame is 1 hour | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Persistence of cognitive enhancements following tDCS |  | The average time frame is 1 hour | 
| Initiation, endurance and cessation of skin sensations caused by tDCS | The initiation, endurance and cessation of skin sensations caused by tDCS will be examined in order to develop a more effective blinding procedure. | The average time frame is 1 hour | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Normal cognitive function, Aphasia, Autism, Schizophrenia