Brief Summary

Investigation of frequency specific transcranial alternating current stimulation on cognitive control signals in frontal cortex

Trial Health

On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment

participants targeted

Target at below P25 for not_applicable

Timeline

Completed

Started Oct 2018

Shorter than P25 for not_applicable

Geographic Reach

1 country

1 active site

Status

completed

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

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Study Timeline

Key milestones and dates

10 months study duration

Study Start

First participant enrolled

October 7, 2018

Completed

2 months until next milestone

First Submitted

Initial submission to the registry

December 18, 2018

Completed

23 days until next milestone

First Posted

Study publicly available on registry

January 10, 2019

Completed

7 months until next milestone

Primary Completion

Last participant's last visit for primary outcome

July 25, 2019

Completed

Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

July 25, 2019

Completed

10 months until next milestone

Results Posted

Study results publicly available

May 18, 2020

Completed

Last Updated

May 18, 2020

Status Verified

September 1, 2019

Enrollment Period

10 months

First QC Date

December 18, 2018

Results QC Date

May 1, 2020

Last Update Submit

May 1, 2020

Conditions

Cognitive Control Executive Function

Keywords

tACSCognitive ControlExecutive Function

Outcome Measures

Primary Outcomes (6)

Reaction Time for Trials With High Abstraction Relative to Low Abstraction
For low abstraction conditions, subjects must memorize a color to button mapping. For high abstraction conditions, subject must make a perceptual judgement on the similarity of two objects based on either texture or shape as cued by a color. The reaction time difference between high and low abstraction conditions was hypothesized to decrease when delta-beta tACS was delivered. As a control for the placebo effect of stimulation, the difference between delta-beta tACS and sham tACS, or placebo, was used for statistical analysis.
through study completion, an average of 3 weeks
Reaction Time for Trials With High Set-size Relative to Low Set-size
The reaction time difference between high and low set-size conditions was hypothesized to decrease when theta-gamma tACS is delivered. As a control for the placebo effect of stimulation, the difference between theta-gamma tACS and sham tACS, or placebo, was used for statistical analysis.
through study completion, an average of 3 weeks
Delta Phase to Beta Amplitude Coupling Strength
Delta-beta tACS was hypothesized to increase cross frequency coupling strength (higher value) between the targeted frequency bands. Phase amplitude coupling between delta phase and beta amplitude was calculated for the two minute electrical brain recordings after stimulation. A null distribution was calculated by shuffling the beta amplitude time series relative to the delta phase time series and then calculating coupling strength. The outcome measure is the z-transformed value of the genuine phase amplitude coupling relative to the null distribution.
through study completion, an average of 3 weeks
Theta Phase to Gamma Amplitude Coupling Strength
Theta-gamma tACS was hypothesized to increase cross frequency coupling strength (higher value) between the targeted frequency bands. Phase amplitude coupling between theta phase and gamma amplitude was calculated for the two minute electrical brain recordings after stimulation. A null distribution was calculated by shuffling the gamma amplitude time series relative to the theta phase time series and then calculating coupling strength. The outcome measure is the z-transformed value of the genuine phase amplitude coupling relative to the null distribution.
through study completion, an average of 3 weeks
Percent Correct for Trials With High Abstraction Relative to Low Abstraction
For low abstraction conditions, subjects must memorize a color to button mapping. For high abstraction conditions, subject must make a perceptual judgement on the similarity of two objects based on either texture or shape as cued by a color. The accuracy difference between high and low abstraction conditions was hypothesized to decrease when delta-beta tACS was delivered. As a control for the placebo effect of stimulation, the difference between delta-beta tACS and sham tACS, or placebo, was used for statistical analysis.
through study completion, an average of 3 weeks
Percent Correct for Trials With High Set-size Relative to Low Set-size
The accuracy difference between high and low set-size conditions was hypothesized to decrease when theta-gamma tACS is delivered. As a control for the placebo effect of stimulation, the difference between theta-gamma tACS and sham tACS, or placebo, was used for statistical analysis.
through study completion, an average of 3 weeks

Study Arms (6)

Theta-gamma, Delta-beta, Sham

EXPERIMENTAL

Every participant will receive Theta-gamma tACS, Delta-beta tACS, and Sham tACS on separate sessions during performance of a computerized task. Sequence: Theta-gamma tACS, then Delta-beta tACS, then Sham tACS