Trial Outcomes & Findings for Home-based Brain Stimulation Treatment for Post-acute Sequelae of COVID-19 (PASC) (NCT NCT05092516)

NCT ID: NCT05092516

Last Updated: 2026-04-30

Results Overview

Performance during the incongruent trials of the Eriksen Flanker Task were assessed at baseline (before the beginning of the 4-week home tDCS intervention). The performance is quantified as the ratio of correct responses to all responses. For example, a score of 0.70 indicates that the participant responded to 70% of the trials correctly.

Recruitment status

ACTIVE_NOT_RECRUITING

Study phase

NA

Target enrollment

31 participants

Primary outcome timeframe

Baseline

Results posted on

2026-04-30

Participant Flow

Participant milestones

Participant milestones
Measure
Active tDCS
This group will receive daily active stimulation (2 mA) to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
Sham tDCS
This group will receive daily sham stimulation to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
Overall Study
STARTED
16
15
Overall Study
COMPLETED
12
12
Overall Study
NOT COMPLETED
4
3

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Home-based Brain Stimulation Treatment for Post-acute Sequelae of COVID-19 (PASC)

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure
Active tDCS
n=16 Participants
This group will receive daily active stimulation (2 mA) to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
Sham tDCS
n=15 Participants
This group will receive daily sham stimulation to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
Total
n=31 Participants
Total of all reporting groups
Age, Continuous
46.2 years
STANDARD_DEVIATION 15 • n=14 Participants
43.1 years
STANDARD_DEVIATION 10.5 • n=34 Participants
44.7 years
STANDARD_DEVIATION 12.9 • n=69 Participants
Sex: Female, Male
Female
11 Participants
n=14 Participants
12 Participants
n=34 Participants
23 Participants
n=69 Participants
Sex: Female, Male
Male
5 Participants
n=14 Participants
3 Participants
n=34 Participants
8 Participants
n=69 Participants
Race (NIH/OMB)
American Indian or Alaska Native
0 Participants
n=14 Participants
0 Participants
n=34 Participants
0 Participants
n=69 Participants
Race (NIH/OMB)
Asian
2 Participants
n=14 Participants
1 Participants
n=34 Participants
3 Participants
n=69 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
0 Participants
n=14 Participants
0 Participants
n=34 Participants
0 Participants
n=69 Participants
Race (NIH/OMB)
Black or African American
0 Participants
n=14 Participants
0 Participants
n=34 Participants
0 Participants
n=69 Participants
Race (NIH/OMB)
White
14 Participants
n=14 Participants
14 Participants
n=34 Participants
28 Participants
n=69 Participants
Race (NIH/OMB)
More than one race
0 Participants
n=14 Participants
0 Participants
n=34 Participants
0 Participants
n=69 Participants
Race (NIH/OMB)
Unknown or Not Reported
0 Participants
n=14 Participants
0 Participants
n=34 Participants
0 Participants
n=69 Participants
Ethnicity (NIH/OMB)
Hispanic or Latino
1 Participants
n=14 Participants
1 Participants
n=34 Participants
2 Participants
n=69 Participants
Ethnicity (NIH/OMB)
Not Hispanic or Latino
15 Participants
n=14 Participants
14 Participants
n=34 Participants
29 Participants
n=69 Participants
Ethnicity (NIH/OMB)
Unknown or Not Reported
0 Participants
n=14 Participants
0 Participants
n=34 Participants
0 Participants
n=69 Participants
Region of Enrollment
United States
16 Participants
n=14 Participants
15 Participants
n=34 Participants
31 Participants
n=69 Participants

PRIMARY outcome

Timeframe: Baseline

Population: Data for this outcome were missing at either baseline or posttreatment time points for 3 participants.

Performance during the incongruent trials of the Eriksen Flanker Task were assessed at baseline (before the beginning of the 4-week home tDCS intervention). The performance is quantified as the ratio of correct responses to all responses. For example, a score of 0.70 indicates that the participant responded to 70% of the trials correctly.

Outcome measures

Outcome measures
Measure
Active tDCS
n=10 Participants
This group will receive daily active stimulation (2 mA) to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
Sham tDCS
n=11 Participants
This group will receive daily sham stimulation to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
Inhibitory Control
0.80 Ratio of correct responses
Standard Deviation 0.08
0.79 Ratio of correct responses
Standard Deviation 0.11

PRIMARY outcome

Timeframe: Posttreatment (1 month follow-up)

Population: Data for this outcome were missing at either baseline or posttreatment time points for 3 participants.

Performance during the incongruent trials of the Eriksen Flanker Task were assessed approximately approximately 4-weeks after baseline. The performance is quantified as the ratio of correct responses to all responses. For example, a score of 0.70 indicates that the participant responded to 70% of the trials correctly.

Outcome measures

Outcome measures
Measure
Active tDCS
n=10 Participants
This group will receive daily active stimulation (2 mA) to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
Sham tDCS
n=11 Participants
This group will receive daily sham stimulation to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
Inhibitory Control
0.84 Ratio of correct responses
Standard Deviation 0.09
0.82 Ratio of correct responses
Standard Deviation 0.1

PRIMARY outcome

Timeframe: Baseline

Population: Data for this outcome were missing at either baseline or posttreatment time points for 3 participants.

Reaction time during the incongruent trials of the Eriksen Flanker Task were assessed at baseline (before the beginning of the 4-week home tDCS intervention)

Outcome measures

Outcome measures
Measure
Active tDCS
n=10 Participants
This group will receive daily active stimulation (2 mA) to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
Sham tDCS
n=11 Participants
This group will receive daily sham stimulation to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
Processing Speed
424.1 miliseconds
Standard Deviation 39
406.9 miliseconds
Standard Deviation 42.7

PRIMARY outcome

Timeframe: Posttreatment (1 month follow-up)

Population: Data for this outcome were missing at either baseline or posttreatment time points for 3 participants.

Reaction time during the incongruent trials of the Eriksen Flanker Task were assessed approximately 4-weeks after baseline.

Outcome measures

Outcome measures
Measure
Active tDCS
n=10 Participants
This group will receive daily active stimulation (2 mA) to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
Sham tDCS
n=11 Participants
This group will receive daily sham stimulation to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
Processing Speed
412.3 miliseconds
Standard Deviation 35.8
403.9 miliseconds
Standard Deviation 38.9

PRIMARY outcome

Timeframe: Baseline

Population: Data for this outcome were missing at either baseline or posttreatment time points for 4 participants.

EEG P300 amplitudes time-locked to the incongruent trials of the Eriksen Flanker Task were assessed at baseline (before the beginning of the 4-week home tDCS intervention). EEG event-related potential amplitudes (measured in microvolts, µV) were normalized across EEG channels using a scaling procedure, in which each channel was rescaled to reduce variability in signal magnitude among electrodes while preserving temporal and spectral characteristics. While larger P300 amplitudes are typically associated with better cognitive outcomes, this can vary among study populations.

Outcome measures

Outcome measures
Measure
Active tDCS
n=9 Participants
This group will receive daily active stimulation (2 mA) to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
Sham tDCS
n=11 Participants
This group will receive daily sham stimulation to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
EEG P300 Event-related Potential
0.59 microvolts
Standard Deviation 0.50
0.64 microvolts
Standard Deviation 0.38

PRIMARY outcome

Timeframe: Posttreatment (1 month follow-up)

Population: Data for this outcome were missing at either baseline or posttreatment time points for 4 participants.

EEG P300 amplitudes time-locked to the incongruent trials of the Eriksen Flanker Task were assessed approximately 4-weeks after baseline. EEG event-related potential amplitudes (measured in microvolts, µV) were normalized across EEG channels using a scaling procedure, in which each channel was rescaled to reduce variability in signal magnitude among electrodes while preserving temporal and spectral characteristics. While larger P300 amplitudes are typically associated with better cognitive outcomes, this can vary among study populations.

Outcome measures

Outcome measures
Measure
Active tDCS
n=9 Participants
This group will receive daily active stimulation (2 mA) to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
Sham tDCS
n=11 Participants
This group will receive daily sham stimulation to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
EEG P300 Event-related Potential
0.62 microvolts
Standard Deviation 0.63
0.85 microvolts
Standard Deviation 0.52

SECONDARY outcome

Timeframe: Baseline

Performance on the NIH Toolbox Dimensional Change Card Sort Test, a computerized measure of executive function assessing cognitive flexibility, attention, and set-shifting. Participants match target stimuli based on changing rules (e.g., color or shape). Scores are reported as fully corrected (for age, gender, race/ethnicity, and education) T-scores (mean = 50, SD = 10), with higher scores indicating better cognitive flexibility and executive control.

Outcome measures

Outcome measures
Measure
Active tDCS
n=12 Participants
This group will receive daily active stimulation (2 mA) to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
Sham tDCS
n=12 Participants
This group will receive daily sham stimulation to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
Cognitive Flexibility
41.4 Performance score (higher the better)
Standard Deviation 11.7
40 Performance score (higher the better)
Standard Deviation 12

SECONDARY outcome

Timeframe: Posttreatment (1 month follow-up)

Performance on the NIH Toolbox Dimensional Change Card Sort Test, a computerized measure of executive function assessing cognitive flexibility, attention, and set-shifting. Participants match target stimuli based on changing rules (e.g., color or shape). Scores are reported as fully corrected (for age, gender, race/ethnicity, and education) T-scores (mean = 50, SD = 10), with higher scores indicating better cognitive flexibility and executive control.

Outcome measures

Outcome measures
Measure
Active tDCS
n=12 Participants
This group will receive daily active stimulation (2 mA) to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
Sham tDCS
n=12 Participants
This group will receive daily sham stimulation to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
Cognitive Flexibility
47.5 Performance score (higher the better)
Standard Deviation 10.6
44.1 Performance score (higher the better)
Standard Deviation 15.3

SECONDARY outcome

Timeframe: Baseline

Performance on the NIH Toolbox List Sorting Working Memory Test, which assesses working memory capacity through sequencing and recall of visually and verbally presented stimuli in size order. The task requires temporary storage and manipulation of information across increasing list lengths. Scores are reported as fully corrected (for age, gender, race/ethnicity, and education) T-scores (mean = 50, SD = 10), with higher scores indicating better working memory performance.

Outcome measures

Outcome measures
Measure
Active tDCS
n=12 Participants
This group will receive daily active stimulation (2 mA) to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
Sham tDCS
n=12 Participants
This group will receive daily sham stimulation to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
Working Memory
46.9 Performance score (higher the better)
Standard Deviation 8.7
43.7 Performance score (higher the better)
Standard Deviation 10.6

SECONDARY outcome

Timeframe: Posttreatment (1 month follow-up)

Performance on the NIH Toolbox List Sorting Working Memory Test, which assesses working memory capacity through sequencing and recall of visually and verbally presented stimuli in size order. The task requires temporary storage and manipulation of information across increasing list lengths. Scores are reported as fully corrected (for age, gender, race/ethnicity, and education) T-scores (mean = 50, SD = 10), with higher scores indicating better working memory performance.

Outcome measures

Outcome measures
Measure
Active tDCS
n=12 Participants
This group will receive daily active stimulation (2 mA) to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
Sham tDCS
n=12 Participants
This group will receive daily sham stimulation to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
Working Memory
52.1 Performance score (higher the better)
Standard Deviation 7.7
50.1 Performance score (higher the better)
Standard Deviation 15.3

SECONDARY outcome

Timeframe: Baseline

Performance on the NIH Toolbox Picture Sequence Memory Test, a measure of episodic memory in which participants reproduce the order of a sequence of visually presented pictures. The task assesses the ability to encode, store, and retrieve sequential information. Scores are reported as fully corrected (for age, gender, race/ethnicity, and education) T-scores (mean = 50, SD = 10), with higher scores indicating better episodic memory function.

Outcome measures

Outcome measures
Measure
Active tDCS
n=12 Participants
This group will receive daily active stimulation (2 mA) to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
Sham tDCS
n=12 Participants
This group will receive daily sham stimulation to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
Episodic Memory
56.4 Performance score (higher the better)
Standard Deviation 11.9
52.5 Performance score (higher the better)
Standard Deviation 14.9

SECONDARY outcome

Timeframe: Posttreatment (1 month follow-up)

Performance on the NIH Toolbox Picture Sequence Memory Test, a measure of episodic memory in which participants reproduce the order of a sequence of visually presented pictures. The task assesses the ability to encode, store, and retrieve sequential information. Scores are reported as fully corrected (for age, gender, race/ethnicity, and education) T-scores (mean = 50, SD = 10), with higher scores indicating better episodic memory function.

Outcome measures

Outcome measures
Measure
Active tDCS
n=12 Participants
This group will receive daily active stimulation (2 mA) to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
Sham tDCS
n=12 Participants
This group will receive daily sham stimulation to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
Episodic Memory
59.1 Performance score (higher the better)
Standard Deviation 12.2
57.5 Performance score (higher the better)
Standard Deviation 18

Adverse Events

Active tDCS

Serious events: 0 serious events
Other events: 7 other events
Deaths: 0 deaths

Sham tDCS

Serious events: 0 serious events
Other events: 9 other events
Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Other adverse events
Measure
Active tDCS
n=16 participants at risk
This group will receive daily active stimulation (2 mA) to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
Sham tDCS
n=15 participants at risk
This group will receive daily sham stimulation to the left dorsolateral prefrontal cortex for 4 weeks through a home-based tDCS device in remotely-supervised 30-min sessions.
General disorders
Warmth sensation
6.2%
1/16 • from baseline until end of treatment (4-weeks)
13.3%
2/15 • from baseline until end of treatment (4-weeks)
General disorders
Distractibility
31.2%
5/16 • from baseline until end of treatment (4-weeks)
40.0%
6/15 • from baseline until end of treatment (4-weeks)
General disorders
Headache
6.2%
1/16 • from baseline until end of treatment (4-weeks)
26.7%
4/15 • from baseline until end of treatment (4-weeks)
General disorders
Neck pain
6.2%
1/16 • from baseline until end of treatment (4-weeks)
6.7%
1/15 • from baseline until end of treatment (4-weeks)
General disorders
Scalp pain
6.2%
1/16 • from baseline until end of treatment (4-weeks)
0.00%
0/15 • from baseline until end of treatment (4-weeks)
General disorders
Skin tingling
6.2%
1/16 • from baseline until end of treatment (4-weeks)
13.3%
2/15 • from baseline until end of treatment (4-weeks)

Additional Information

Hamdi Eryilmaz, PhD

Massachusetts General Hospital

Phone: (617) 643-7462

Results disclosure agreements

  • Principal investigator is a sponsor employee
  • Publication restrictions are in place