Trial Outcomes & Findings for Traveling-wave Transcranial Electric Stimulation (NCT NCT05399381)
NCT ID: NCT05399381
Last Updated: 2026-08-20
Results Overview
Accuracy (proportion of correct responses) during performance of the N-back working memory task within each stimulation block. Values represent absolute task performance during active or sham stimulation in a within-subject crossover design.
Recruitment status
COMPLETED
Study phase
NA
Target enrollment
34 participants
Primary outcome timeframe
During each stimulation block (approximately 20 minutes per block) in two study sessions conducted on separate days and separated by a minimum 48-hour washout period.
Results posted on
2026-08-20
Participant Flow
A total of 34 participants were enrolled in the study. Of these, 29 participants completed all study procedures and received all stimulation conditions.
All participants were assigned to a single randomized within-subject crossover arm. Each participant completed two study sessions separated by a washout period, receiving two active stimulation conditions per session. Across both sessions, every participant received all four active stimulation conditions exactly once. Counts shown for individual conditions are session-specific and do not represent separate treatment arms.
Participant milestones
| Measure |
All Study Participants
Participants were enrolled in a randomized, triple-blind, sham-controlled, within-subject crossover study. Each participant completed two stimulation sessions separated by a minimum 48-hour washout period. During each session, participants received two active stimulation blocks separated by a sham stimulation block, resulting in two active conditions being administered in Session 1 and the remaining two active conditions being administered in Session 2.
Across both sessions, each participant received all four active stimulation conditions: Frontoparietal Slow Theta (4 Hz, 45° phase difference), Parietofrontal Slow Theta (4 Hz, 315° phase difference), Frontoparietal Fast Theta (7 Hz, 45° phase difference), and Parietofrontal Fast Theta (7 Hz, 315° phase difference).
Randomization determined both (1) which two active stimulation conditions were assigned to each session and (2) the order in which the four active conditions were administered across the four active stimulation blocks. Thus, participants were randomized to different crossover sequences while all participants received the same four active stimulation conditions. The sham stimulation block was fixed between the two active stimulation blocks within each session to minimize potential carryover effects. Baseline characteristics are presented for the overall study population prior to receiving any stimulation.
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|---|---|
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Overall Study
STARTED
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34
|
|
Overall Study
Received Frontoparietal Slow Theta Stimulation
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29
|
|
Overall Study
Frontoparietal Slow Theta (4 Hz, 45°)
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15
|
|
Overall Study
Parietofrontal Slow Theta (4 Hz, 315°)
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13
|
|
Overall Study
Frontoparietal Fast Theta (7 Hz, 45°)
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14
|
|
Overall Study
Parietofrontal Fast Theta (7 Hz, 315°)
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16
|
|
Overall Study
Total Active Stimulation Conditions Administered
|
58
|
|
Overall Study
Active Conditions Received by Each Participant
|
2
|
|
Overall Study
COMPLETED
|
29
|
|
Overall Study
NOT COMPLETED
|
5
|
Reasons for withdrawal
| Measure |
All Study Participants
Participants were enrolled in a randomized, triple-blind, sham-controlled, within-subject crossover study. Each participant completed two stimulation sessions separated by a minimum 48-hour washout period. During each session, participants received two active stimulation blocks separated by a sham stimulation block, resulting in two active conditions being administered in Session 1 and the remaining two active conditions being administered in Session 2.
Across both sessions, each participant received all four active stimulation conditions: Frontoparietal Slow Theta (4 Hz, 45° phase difference), Parietofrontal Slow Theta (4 Hz, 315° phase difference), Frontoparietal Fast Theta (7 Hz, 45° phase difference), and Parietofrontal Fast Theta (7 Hz, 315° phase difference).
Randomization determined both (1) which two active stimulation conditions were assigned to each session and (2) the order in which the four active conditions were administered across the four active stimulation blocks. Thus, participants were randomized to different crossover sequences while all participants received the same four active stimulation conditions. The sham stimulation block was fixed between the two active stimulation blocks within each session to minimize potential carryover effects. Baseline characteristics are presented for the overall study population prior to receiving any stimulation.
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|---|---|
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Overall Study
Lost to Follow-up
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1
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|
Overall Study
Could not be fitted with the EEG cap due to head size/hairstyle constraints
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2
|
|
Overall Study
Withdrew after reporting headache (not considered an adverse event)
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2
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Baseline Characteristics
Traveling-wave Transcranial Electric Stimulation
Baseline characteristics by cohort
| Measure |
All Study Participants
n=29 Participants
Participants were enrolled in a randomized, triple-blind, sham-controlled, within-subject crossover study. Participants completed up to two stimulation sessions separated by a minimum 48-hour washout period. During each session, participants received two active stimulation conditions and one sham stimulation block. The four active stimulation conditions were Frontoparietal Slow Theta (4 Hz, 45° phase difference), Parietofrontal Slow Theta (4 Hz, 315° phase difference), Frontoparietal Fast Theta (7 Hz, 45° phase difference), and Parietofrontal Fast Theta (7 Hz, 315° phase difference). Active stimulation conditions were assigned in randomized order across sessions. Baseline characteristics are presented for the overall study population prior to receiving any stimulation.
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|---|---|
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Age, Categorical
<=18 years
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0 Participants
n=5 Participants
|
|
Age, Categorical
Between 18 and 65 years
|
29 Participants
n=5 Participants
|
|
Age, Categorical
>=65 years
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0 Participants
n=5 Participants
|
|
Sex: Female, Male
Female
|
14 Participants
n=5 Participants
|
|
Sex: Female, Male
Male
|
15 Participants
n=5 Participants
|
|
Race (NIH/OMB)
American Indian or Alaska Native
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0 Participants
n=5 Participants
|
|
Race (NIH/OMB)
Asian
|
0 Participants
n=5 Participants
|
|
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
|
0 Participants
n=5 Participants
|
|
Race (NIH/OMB)
Black or African American
|
0 Participants
n=5 Participants
|
|
Race (NIH/OMB)
White
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0 Participants
n=5 Participants
|
|
Race (NIH/OMB)
More than one race
|
0 Participants
n=5 Participants
|
|
Race (NIH/OMB)
Unknown or Not Reported
|
29 Participants
n=5 Participants
|
PRIMARY outcome
Timeframe: During each stimulation block (approximately 20 minutes per block) in two study sessions conducted on separate days and separated by a minimum 48-hour washout period.Population: All participants were enrolled in a randomized, within-subject crossover design and received all stimulation conditions across two sessions
Accuracy (proportion of correct responses) during performance of the N-back working memory task within each stimulation block. Values represent absolute task performance during active or sham stimulation in a within-subject crossover design.
Outcome measures
| Measure |
Frontoparietal Slow Theta Stimulation
n=29 Participants
Participants will receive multi-electrode transcranial alternating current stimulation over the prefrontal and parietal brain regions that induces frontal-to-parietal traveling wave at the frequency of 4 Hz with the intensity of up to 2 mA and duration up to 20 min.
Transcranial alternating current stimulation (tACS): Non-invasive, multi-electrode transcranial alternating current stimulation (tACS) over frontal and parietal brain areas.
|
Frontoparietal Fast Theta Stimulation
n=29 Participants
Participants will receive multi-electrode transcranial alternating current stimulation over the prefrontal and parietal brain regions that induces frontal-to-parietal traveling wave at the frequency of 7 Hz with the intensity of up to 2 mA and duration up to 20 min.
Transcranial alternating current stimulation (tACS): Non-invasive, multi-electrode transcranial alternating current stimulation (tACS) over frontal and parietal brain areas.
|
Parietofrontal Slow Theta Stimulation
n=29 Participants
Participants will receive multi-electrode transcranial alternating current stimulation over the prefrontal and parietal brain regions that induces parietal-to-frontal traveling wave at the frequency of 4 Hz with the intensity of up to 2 mA and duration up to 20 min.
Transcranial alternating current stimulation (tACS): Non-invasive, multi-electrode transcranial alternating current stimulation (tACS) over frontal and parietal brain areas.
|
Parietofrontal Fast Theta Stimulation
n=29 Participants
Participants will receive multi-electrode transcranial alternating current stimulation over the prefrontal and parietal brain regions that induces parietal-to-frontal traveling wave at the frequency of 7 Hz with the intensity of up to 2 mA and duration up to 20 min.
Transcranial alternating current stimulation (tACS): Non-invasive, multi-electrode transcranial alternating current stimulation (tACS) over frontal and parietal brain areas.
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|---|---|---|---|---|
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Working Memory Accuracy (N-back Task)
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0.77 proportion
Standard Deviation 0.11
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0.79 proportion
Standard Deviation 0.13
|
0.82 proportion
Standard Deviation 0.1
|
0.78 proportion
Standard Deviation 0.1
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SECONDARY outcome
Timeframe: During each stimulation block (approximately 20 minutes per block) in two study sessions conducted on separate days and separated by a minimum 48-hour washout period.Population: All participants were enrolled in a randomized, within-subject crossover design and received all stimulation conditions across two sessions
Reaction time (milliseconds) during performance of the N-back working memory task within each stimulation block. Values represent absolute reaction time during active or sham stimulation conditions in a within-subject crossover design
Outcome measures
| Measure |
Frontoparietal Slow Theta Stimulation
n=29 Participants
Participants will receive multi-electrode transcranial alternating current stimulation over the prefrontal and parietal brain regions that induces frontal-to-parietal traveling wave at the frequency of 4 Hz with the intensity of up to 2 mA and duration up to 20 min.
Transcranial alternating current stimulation (tACS): Non-invasive, multi-electrode transcranial alternating current stimulation (tACS) over frontal and parietal brain areas.
|
Frontoparietal Fast Theta Stimulation
n=29 Participants
Participants will receive multi-electrode transcranial alternating current stimulation over the prefrontal and parietal brain regions that induces frontal-to-parietal traveling wave at the frequency of 7 Hz with the intensity of up to 2 mA and duration up to 20 min.
Transcranial alternating current stimulation (tACS): Non-invasive, multi-electrode transcranial alternating current stimulation (tACS) over frontal and parietal brain areas.
|
Parietofrontal Slow Theta Stimulation
n=29 Participants
Participants will receive multi-electrode transcranial alternating current stimulation over the prefrontal and parietal brain regions that induces parietal-to-frontal traveling wave at the frequency of 4 Hz with the intensity of up to 2 mA and duration up to 20 min.
Transcranial alternating current stimulation (tACS): Non-invasive, multi-electrode transcranial alternating current stimulation (tACS) over frontal and parietal brain areas.
|
Parietofrontal Fast Theta Stimulation
n=29 Participants
Participants will receive multi-electrode transcranial alternating current stimulation over the prefrontal and parietal brain regions that induces parietal-to-frontal traveling wave at the frequency of 7 Hz with the intensity of up to 2 mA and duration up to 20 min.
Transcranial alternating current stimulation (tACS): Non-invasive, multi-electrode transcranial alternating current stimulation (tACS) over frontal and parietal brain areas.
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|---|---|---|---|---|
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Changes in Reaction Time
|
626.26 ms
Standard Deviation 193.46
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710.71 ms
Standard Deviation 215.8
|
694.57 ms
Standard Deviation 212.93
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670.22 ms
Standard Deviation 206.62
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SECONDARY outcome
Timeframe: Resting-state EEG was recorded immediately before and immediately after each stimulation block in two sessions conducted on separate days (≥48-hour washout).Population: All participants were enrolled in a randomized, within-subject crossover design and received all stimulation conditions across two sessions
Frontoparietal phase synchronization in the theta band (4-7 Hz), quantified using the debiased weighted Phase-Lag Index (dwPLI) between frontal and parietal electrode pairs. Connectivity values range from 0 to 1, with higher values indicating stronger phase synchronization
Outcome measures
| Measure |
Frontoparietal Slow Theta Stimulation
n=29 Participants
Participants will receive multi-electrode transcranial alternating current stimulation over the prefrontal and parietal brain regions that induces frontal-to-parietal traveling wave at the frequency of 4 Hz with the intensity of up to 2 mA and duration up to 20 min.
Transcranial alternating current stimulation (tACS): Non-invasive, multi-electrode transcranial alternating current stimulation (tACS) over frontal and parietal brain areas.
|
Frontoparietal Fast Theta Stimulation
n=29 Participants
Participants will receive multi-electrode transcranial alternating current stimulation over the prefrontal and parietal brain regions that induces frontal-to-parietal traveling wave at the frequency of 7 Hz with the intensity of up to 2 mA and duration up to 20 min.
Transcranial alternating current stimulation (tACS): Non-invasive, multi-electrode transcranial alternating current stimulation (tACS) over frontal and parietal brain areas.
|
Parietofrontal Slow Theta Stimulation
n=29 Participants
Participants will receive multi-electrode transcranial alternating current stimulation over the prefrontal and parietal brain regions that induces parietal-to-frontal traveling wave at the frequency of 4 Hz with the intensity of up to 2 mA and duration up to 20 min.
Transcranial alternating current stimulation (tACS): Non-invasive, multi-electrode transcranial alternating current stimulation (tACS) over frontal and parietal brain areas.
|
Parietofrontal Fast Theta Stimulation
n=29 Participants
Participants will receive multi-electrode transcranial alternating current stimulation over the prefrontal and parietal brain regions that induces parietal-to-frontal traveling wave at the frequency of 7 Hz with the intensity of up to 2 mA and duration up to 20 min.
Transcranial alternating current stimulation (tACS): Non-invasive, multi-electrode transcranial alternating current stimulation (tACS) over frontal and parietal brain areas.
|
|---|---|---|---|---|
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Theta-band Frontoparietal EEG Phase Connectivity (dwPLI)
|
-0.008 dwPLI value
Standard Deviation 0.04
|
0.02 dwPLI value
Standard Deviation 0.04
|
0.06 dwPLI value
Standard Deviation 0.07
|
0.01 dwPLI value
Standard Deviation 0.05
|
Adverse Events
Frontoparietal Slow Theta Stimulation
Serious events: 0 serious events
Other events: 0 other events
Deaths: 0 deaths
Frontoparietal Fast Theta Stimulation
Serious events: 0 serious events
Other events: 0 other events
Deaths: 0 deaths
Parietofrontal Slow Theta Stimulation
Serious events: 0 serious events
Other events: 0 other events
Deaths: 0 deaths
Parietofrontal Fast Theta Stimulation
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
Results disclosure agreements
- Principal investigator is a sponsor employee
- Publication restrictions are in place