At-home Transcranial Alternating Current Stimulation During Multitasking

Study Overview
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Brief Summary
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The goal is to replicate in-lab results from transcranial alternating current stimulation (tACS) with at-home tACS.

Detailed Description
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Participants will be assessed in-lab on multitasking and sustained attention abilities. Participants will be sent home with a tACS device to be used at-home for five days while engaged in a multitasking paradigm that is different from the multitasking outcome measure used pre/post tACS. After the at-home stimulation is complete, participants return to UCSF for a final in-lab assessment of multitasking and sustained attention ability.

Official Title
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At-home Transcranial Alternating Current Stimulation During Multitasking

Conditions
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Multitasking Behavior

Intervention / Treatment
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* Device: Transcranial alternating current stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: English speaking Grade 12 or more education Normal or corrected to normal vision and hearing Ability to complete cognitive tasks Ability to cooperate and comply with all study procedures Ability to tolerate tACS Exclusion Criteria: Neurological or psychiatric disorders Family history of epilepsy History of seizures Prior head trauma Pregnant Implanted electronic devices (e.g., pacemaker) IQ < 80 Taking psychotropic medication Taking anti-depressants or anti-anxiety medication Substance abuse Color blind Glaucoma Macular degeneration Amblyopia Strabismus

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 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
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Verum Stimulation<br>This group will receive 6-Hz tACS | Device: Transcranial alternating current stimulation<br>* Transcranial alternating current stimulation across the prefrontal cortex using electrodes F3 and F4.<br>|
| Active Comparator: Frequency Control<br>This group will receive 1-Hz tACS | Device: Transcranial alternating current stimulation<br>* Transcranial alternating current stimulation across the prefrontal cortex using electrodes F3 and F4.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Multitasking Performance Cost (Neuroracer Performance Change From Baseline) | Assessment of multitasking ability using change from baseline scores in d' cost (metric of discriminability). Discrimination performance (d') was measured for each participant by comparing hit (correct responses to target signs) rates and false alarm (responses to non-targets) rates and calculated as d' = Z (hits) - Z (false alarms). d' cost was then calculated as the ratio of d' during single task target discrimination task to multitask target discrimination, expressed as percentage cost. | Pre-tACS and post-tACS (1 week later) | 
| Single Task Performance Change | Discrimination performance (d') was measured during single task performance for each participant by comparing hit (correct responses to target signs) rates and false alarm (responses to non-targets) rates and calculated as d' = Z (hits) - Z (false alarms). Performance data was collected during the single task condition. | Pre-tACS and post-tACS (1 week later) | 
| Multitask Performance Change | Discrimination performance (d') was measured while multitasking for each participant by comparing hit (correct responses to target signs) rates and false alarm (responses to non-targets) rates and calculated as d' = Z (hits) - Z (false alarms). Performance data was collected during the multitask condition. | Pre-tACS and post-tACS (1 week later) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Continuous Performance Test RT Change (Test of Visual Attention / Sustained Attention) | Assessment of sustained attention ability using response time (in ms) during the continuous performance test | Pre-tACS and post-tACS (1 week later) | 
| Continuous Performance Test RTV Change (Test of Visual Attention / Sustained Attention) | Assessment of sustained attention ability using response time variability (standard deviation of response times in ms) during the continuous performance test | Pre-tACS and post-tACS (1 week later) |