Trial Outcomes & Findings for Bipolar Transcranial Alternating Current Stimulation (tACS) (NCT NCT05480124)

Results Overview

The score was calculated by summing the severity score of items that were rated by the participant as related to stimulation on the Stimulation Side Effects Questionnaire. There was a total of 14 symptoms listed on the questionnaire. Participants rated each item rated on a scale of 0-4, with 0 meaning no relation and 4 meaning definitely related. The total possible range of the questionnaire was 0-56.

Recruitment status

COMPLETED

Study phase

NA

Target enrollment

18 participants

Primary outcome timeframe

Up to 3 weeks

Results posted on

2025-01-14

Participant Flow

Participant milestones

Participant milestones
Measure	Sham First, Then tACS Participants in this arm received the sham stimulation treatment during session 2 and then received the tACS brain stimulation treatment in session 3.	tACS, Then Sham Participants in this arm received the tACS brain stimulation treatment in session 2 and then received the sham stimulation treatment during session 3.
Session 1 (Baseline) STARTED	10	8
Session 1 (Baseline) COMPLETED	10	8
Session 1 (Baseline) NOT COMPLETED	0	0
Session 2 STARTED	10	8
Session 2 COMPLETED	10	8
Session 2 NOT COMPLETED	0	0
Washout STARTED	10	8
Washout COMPLETED	10	8
Washout NOT COMPLETED	0	0
Session 3 STARTED	10	8
Session 3 COMPLETED	10	8
Session 3 NOT COMPLETED	0	0

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Bipolar Transcranial Alternating Current Stimulation (tACS)

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Sham First, Then tACS n=10 Participants Participants in this arm received the sham stimulation treatment during session 2 and then received the tACS brain stimulation treatment in session 3.	tACS, Then Sham n=8 Participants Participants in this arm received the tACS brain stimulation treatment in session 2 and then received the sham stimulation treatment during session 3.	Total n=18 Participants Total of all reporting groups
Age, Continuous	41.4 years STANDARD_DEVIATION 10.03 • n=5 Participants	42.75 years STANDARD_DEVIATION 12.44 • n=7 Participants	42.0 years STANDARD_DEVIATION 10.84 • n=5 Participants
Sex: Female, Male Female	6 Participants n=5 Participants	5 Participants n=7 Participants	11 Participants n=5 Participants
Sex: Female, Male Male	4 Participants n=5 Participants	3 Participants n=7 Participants	7 Participants n=5 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	1 Participants n=5 Participants	0 Participants n=7 Participants	1 Participants n=5 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	9 Participants n=5 Participants	8 Participants n=7 Participants	17 Participants n=5 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) Asian	1 Participants n=5 Participants	1 Participants n=7 Participants	2 Participants n=5 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) Black or African American	1 Participants n=5 Participants	0 Participants n=7 Participants	1 Participants n=5 Participants
Race (NIH/OMB) White	7 Participants n=5 Participants	7 Participants n=7 Participants	14 Participants n=5 Participants
Race (NIH/OMB) More than one race	1 Participants n=5 Participants	0 Participants n=7 Participants	1 Participants n=5 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Region of Enrollment United States	10 Participants n=5 Participants	8 Participants n=7 Participants	18 Participants n=5 Participants

PRIMARY outcome

Timeframe: Up to 3 weeks

The score was calculated by summing the severity score of items that were rated by the participant as related to stimulation on the Stimulation Side Effects Questionnaire. There was a total of 14 symptoms listed on the questionnaire. Participants rated each item rated on a scale of 0-4, with 0 meaning no relation and 4 meaning definitely related. The total possible range of the questionnaire was 0-56.

Outcome measures

Outcome measures
Measure	Sham Stimulation Treatment n=18 Participants Sham stimulation during a computerized task and electroencephalogram (EEG) recording. Sham stimulation treatment: Participants will wear an EEG cap on the head attached with EEG-recording and tACS electrodes. Sham tACS will be delivered by passing a transient (approximately 12 seconds ) small electrical current via the tACS electrodes during a computerized behavioral task. The effect of sham stimulation on EEG will be measured via EEG-recording electrodes during short rests (between stimulation blocks). The sham stimulation session will last for approximately 60 minutes. After treatment, participants will be asked about the experience and if there are any side effects.	tACS Brain Stimulation Treatment n=18 Participants tACS brain stimulation during a computerized task and EEG recording. Participants will receive tACS using individualized peak Phase-amplitude coupling (PAC) frequency pairs determined in Session 1. tACS brain stimulation treatment: Participants will wear an EEG cap on the head attached with EEG-recording and tACS electrodes. tACS will be delivered by passing a small electrical current via the tACS electrodes to the scalp to stimulate brain activity during a computerized behavioral task. The effect of active stimulation on EEG will be measured via EEG-recording electrodes during short rests (between stimulation blocks). The stimulation session will last for approximately 60 minutes. After treatment, participants will be asked about the experience and if there are any side effects.
Severity of Side Effects Reported at End of Stimulation Session as Reported by the Participant on the Stimulation Side Effects Questionnaire.	5.66 score on a scale Standard Deviation 4.47	5.00 score on a scale Standard Deviation 0.90

PRIMARY outcome

Timeframe: Up to 3 weeks

Results reflect the number of participants who withdrew from the trial during or after a stimulation session with either the tACS or the sham stimulation treatment.

Outcome measures

Outcome measures
Measure	Sham Stimulation Treatment n=18 Participants Sham stimulation during a computerized task and electroencephalogram (EEG) recording. Sham stimulation treatment: Participants will wear an EEG cap on the head attached with EEG-recording and tACS electrodes. Sham tACS will be delivered by passing a transient (approximately 12 seconds ) small electrical current via the tACS electrodes during a computerized behavioral task. The effect of sham stimulation on EEG will be measured via EEG-recording electrodes during short rests (between stimulation blocks). The sham stimulation session will last for approximately 60 minutes. After treatment, participants will be asked about the experience and if there are any side effects.	tACS Brain Stimulation Treatment n=18 Participants tACS brain stimulation during a computerized task and EEG recording. Participants will receive tACS using individualized peak Phase-amplitude coupling (PAC) frequency pairs determined in Session 1. tACS brain stimulation treatment: Participants will wear an EEG cap on the head attached with EEG-recording and tACS electrodes. tACS will be delivered by passing a small electrical current via the tACS electrodes to the scalp to stimulate brain activity during a computerized behavioral task. The effect of active stimulation on EEG will be measured via EEG-recording electrodes during short rests (between stimulation blocks). The stimulation session will last for approximately 60 minutes. After treatment, participants will be asked about the experience and if there are any side effects.
Participants Who Withdrew During or After the Stimulation Session	0 Participants	0 Participants

PRIMARY outcome

Timeframe: Up to 3 weeks

The Go/NoGo task was a cognitive task, where participants were shown "go" stimuli (i.e., go trials) and "no-go" stimuli and responded by pressing a button when seeing "go" stimuli and not responding when seeing the "no-go" stimuli. Accuracy was measured by calculating D' (D prime), which provided a measure of perceptual sensitivity to the differing stimuli. Larger values of D' indicated greater discernability (i.e., accuracy) between the Go and NoGo trials. D-prime, also called the sensitivity index represents how well someone can detect a signal amidst background noise. At its core, D-prime is the standardized difference between the means of the Signal Present and Signal Absent distributions, which can be calculated by taking the difference between the Z-score of the False Alarm Rate and the Z-scores of the Hit Rate. A D-prime of 0 means no sensitivity. Negative D-prime values are rare and may indicate errors or reversed interpretations of hits and false alarms.

Outcome measures

Outcome measures
Measure	Sham Stimulation Treatment n=18 Participants Sham stimulation during a computerized task and electroencephalogram (EEG) recording. Sham stimulation treatment: Participants will wear an EEG cap on the head attached with EEG-recording and tACS electrodes. Sham tACS will be delivered by passing a transient (approximately 12 seconds ) small electrical current via the tACS electrodes during a computerized behavioral task. The effect of sham stimulation on EEG will be measured via EEG-recording electrodes during short rests (between stimulation blocks). The sham stimulation session will last for approximately 60 minutes. After treatment, participants will be asked about the experience and if there are any side effects.	tACS Brain Stimulation Treatment n=18 Participants tACS brain stimulation during a computerized task and EEG recording. Participants will receive tACS using individualized peak Phase-amplitude coupling (PAC) frequency pairs determined in Session 1. tACS brain stimulation treatment: Participants will wear an EEG cap on the head attached with EEG-recording and tACS electrodes. tACS will be delivered by passing a small electrical current via the tACS electrodes to the scalp to stimulate brain activity during a computerized behavioral task. The effect of active stimulation on EEG will be measured via EEG-recording electrodes during short rests (between stimulation blocks). The stimulation session will last for approximately 60 minutes. After treatment, participants will be asked about the experience and if there are any side effects.
Accuracy Signal Detection Theory Metric Sensitivity (d') Derived From the Behavioral Responses to Go and NoGo Trials on the Cognitive Control Task.	2.08 z-score Standard Deviation 0.51	2.20 z-score Standard Deviation 0.56

PRIMARY outcome

Timeframe: Up to 3 weeks

The Go/NoGo task was a cognitive task, where participants were shown "go" stimuli (i.e., go trials) and "no-go" stimuli and responded by pressing a button when seeing "go" stimuli and not responding when seeing the "no-go" stimuli. Response bias was measured using beta, such that more negative beta values indicated a stronger tendency to respond to all stimuli, regardless of "go" or "no-go" status. Response bias is indexed by taking the average between the Z-score of the False Alarm Rate and the Z-scores of the Hit Rate. A higher response bias indicates that the participant is more likely to respond "signal absent" (favors avoiding false alarms but increases misses). A response bias of 0 means the individual equally weighs the costs of misses and false alarms. A more negative response bias indicated that the participant is more likely to respond "signal present" (favors hits but increases false alarms).

Outcome measures

Outcome measures
Measure	Sham Stimulation Treatment n=18 Participants Sham stimulation during a computerized task and electroencephalogram (EEG) recording. Sham stimulation treatment: Participants will wear an EEG cap on the head attached with EEG-recording and tACS electrodes. Sham tACS will be delivered by passing a transient (approximately 12 seconds ) small electrical current via the tACS electrodes during a computerized behavioral task. The effect of sham stimulation on EEG will be measured via EEG-recording electrodes during short rests (between stimulation blocks). The sham stimulation session will last for approximately 60 minutes. After treatment, participants will be asked about the experience and if there are any side effects.	tACS Brain Stimulation Treatment n=18 Participants tACS brain stimulation during a computerized task and EEG recording. Participants will receive tACS using individualized peak Phase-amplitude coupling (PAC) frequency pairs determined in Session 1. tACS brain stimulation treatment: Participants will wear an EEG cap on the head attached with EEG-recording and tACS electrodes. tACS will be delivered by passing a small electrical current via the tACS electrodes to the scalp to stimulate brain activity during a computerized behavioral task. The effect of active stimulation on EEG will be measured via EEG-recording electrodes during short rests (between stimulation blocks). The stimulation session will last for approximately 60 minutes. After treatment, participants will be asked about the experience and if there are any side effects.
Accuracy Signal Detection Theory Metric Response Bias Derived From the Behavioral Responses to Go and NoGo Trials on the Cognitive Control Task.	-0.03 z-score Standard Deviation 0.28	-0.05 z-score Standard Deviation 0.22

PRIMARY outcome

Timeframe: Up to 3 weeks

Participants' reaction time to responding to the "Go" signal during the Go/NoGo task was measured.

Outcome measures

Outcome measures
Measure	Sham Stimulation Treatment n=18 Participants Sham stimulation during a computerized task and electroencephalogram (EEG) recording. Sham stimulation treatment: Participants will wear an EEG cap on the head attached with EEG-recording and tACS electrodes. Sham tACS will be delivered by passing a transient (approximately 12 seconds ) small electrical current via the tACS electrodes during a computerized behavioral task. The effect of sham stimulation on EEG will be measured via EEG-recording electrodes during short rests (between stimulation blocks). The sham stimulation session will last for approximately 60 minutes. After treatment, participants will be asked about the experience and if there are any side effects.	tACS Brain Stimulation Treatment n=18 Participants tACS brain stimulation during a computerized task and EEG recording. Participants will receive tACS using individualized peak Phase-amplitude coupling (PAC) frequency pairs determined in Session 1. tACS brain stimulation treatment: Participants will wear an EEG cap on the head attached with EEG-recording and tACS electrodes. tACS will be delivered by passing a small electrical current via the tACS electrodes to the scalp to stimulate brain activity during a computerized behavioral task. The effect of active stimulation on EEG will be measured via EEG-recording electrodes during short rests (between stimulation blocks). The stimulation session will last for approximately 60 minutes. After treatment, participants will be asked about the experience and if there are any side effects.
Reaction Time (in Milliseconds) of Go Trials on the Cognitive Control Task	584.88 milliseconds Standard Deviation 97.55	582.01 milliseconds Standard Deviation 88.98

PRIMARY outcome

Timeframe: Up to 3 weeks

Population: Data was not collected from 1 participant in the sham arm, as their EEG data was unreadable following administration of the sham.

Theta-gamma phase-amplitude coupling (PAC) is a neural phenomenon observed in the brain, where the phase of slower theta oscillations modulates the amplitude of faster gamma oscillations. This type of coupling is thought to play a critical role in various cognitive control. For the trial, higher PAC values indicated higher levels of coupling or connection between the two frequencies (i.e., increased cognitive control).

Outcome measures

Outcome measures
Measure	Sham Stimulation Treatment n=17 Participants Sham stimulation during a computerized task and electroencephalogram (EEG) recording. Sham stimulation treatment: Participants will wear an EEG cap on the head attached with EEG-recording and tACS electrodes. Sham tACS will be delivered by passing a transient (approximately 12 seconds ) small electrical current via the tACS electrodes during a computerized behavioral task. The effect of sham stimulation on EEG will be measured via EEG-recording electrodes during short rests (between stimulation blocks). The sham stimulation session will last for approximately 60 minutes. After treatment, participants will be asked about the experience and if there are any side effects.	tACS Brain Stimulation Treatment n=18 Participants tACS brain stimulation during a computerized task and EEG recording. Participants will receive tACS using individualized peak Phase-amplitude coupling (PAC) frequency pairs determined in Session 1. tACS brain stimulation treatment: Participants will wear an EEG cap on the head attached with EEG-recording and tACS electrodes. tACS will be delivered by passing a small electrical current via the tACS electrodes to the scalp to stimulate brain activity during a computerized behavioral task. The effect of active stimulation on EEG will be measured via EEG-recording electrodes during short rests (between stimulation blocks). The stimulation session will last for approximately 60 minutes. After treatment, participants will be asked about the experience and if there are any side effects.
Theta-gamma Phase Amplitude Coupling (PAC) (Kullback-Leibler Modulation Index) During the Rest EEG Blocks Interleaved Between Stimulation Blocks.	0.14 arbitrary units Standard Deviation 0.12	0.20 arbitrary units Standard Deviation 0.32

OTHER_PRE_SPECIFIED outcome

Timeframe: Approximately 30-60 minutes after the Go-NoGo task at all three time points (baseline, session 1, session 2)

After completing the Emotion Go-NoGo task, participants will complete another cognitive control task (i.e., Emotional Flanker Task) with gray-scaled unpleasant, pleasant, and neural images from the International Affective Picture System. Participants are tasked with indicating which valance is presented in certain images while ignoring other images. Accuracy is defined as the percentage of trials that the participant correctly reports the valance of the target image. The total number of correct trials will be divided by the total number of trials to obtain an accuracy score. Average accuracy scores per condition and total will be calculated.

Outcome measures

Outcome data not reported

OTHER_PRE_SPECIFIED outcome

Timeframe: Approximately 30-60 minutes after the Go-NoGo task at all three time points (baseline, session 1, session 2).

Reaction time will also be collected during the Emotional Flanker Task. Reaction time is defined as the length of time it takes the participant to respond after the onset of the stimuli. Average reaction times per condition and total will be calculated.

Outcome measures

Outcome data not reported

OTHER_PRE_SPECIFIED outcome

Timeframe: Approximately 30-60 minutes after the Go-NoGo task at all three time points (baseline, session 1, session 2).

EEG will also be collected during the Emotional Flanker Task. Phase-amplitude coupling will be calculated and defined as the coupling between the amplitude of high frequency oscillations (e.g., gamma) and low frequency phase (e.g., theta). Average coupling scores per condition and total will be calculated.

Outcome measures

Outcome data not reported

Adverse Events

Sham Stimulation Treatment

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

tACS Brain Stimulation Treatment

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Adverse event data not reported

Additional Information

Stephan Taylor

University of Michigan

Phone: (734) 936-4955

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place