Trial Outcomes & Findings for Task-dependent Effects of TMS on the Neural Biomarkers of Episodic Memory (NCT NCT04694131)

Last Updated: 2025-07-04

Results Overview

Participants completed a memory task with simultaneous EEG acquisition and transcranial magnetic stimulation (TMS) delivered to either a memory-relevant parietal lobe target or a vertex control site. Participants were shown a series of objects in one of four quadrants on the screen, with TMS delivered either prior to or concurrent with the trial onset. They were instructed to remember the object and the location. This outcome measure examines the accuracy of memory for the item and the location (context), presented as the percentage of successful trials. Accuracy is shown for each stimulation condition (parietal or vertex location, before or during the trial)

Recruitment status

COMPLETED

Study phase

Target enrollment

43 participants

Primary outcome timeframe

1 hour

Results posted on

2025-07-04

Participant Flow

Participants were recruited from the NIH healthy volunteer database and the NIH postbac list serve, as well as individuals who self-referred. Recruitment of study participants occurred from July 2021 to February 2023.

43 participants were consented to the study and 32 participants successfully completed all study requirements.

Participant milestones

Participant milestones
Measure	Healthy Participants Healthy participants undergoing all study procedures
Overall Study STARTED	43
Overall Study COMPLETED	32
Overall Study NOT COMPLETED	11

Reasons for withdrawal

Reasons for withdrawal
Measure	Healthy Participants Healthy participants undergoing all study procedures
Overall Study Withdrawal by Subject	7
Overall Study Screen Failure	1
Overall Study High stimulation threshold	3

Baseline Characteristics

Task-dependent Effects of TMS on the Neural Biomarkers of Episodic Memory

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Healthy Participants n=32 Participants Healthy participants undergoing all study procedures
Age, Categorical <=18 years	0 Participants n=5 Participants
Age, Categorical Between 18 and 65 years	32 Participants n=5 Participants
Age, Categorical >=65 years	0 Participants n=5 Participants
Age, Continuous	25.1 years STANDARD_DEVIATION 4.2 • n=5 Participants
Sex: Female, Male Female	19 Participants n=5 Participants
Sex: Female, Male Male	13 Participants n=5 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	5 Participants n=5 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	27 Participants n=5 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=5 Participants
Race (NIH/OMB) Asian	8 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	8 Participants n=5 Participants
Race (NIH/OMB) White	15 Participants n=5 Participants
Race (NIH/OMB) More than one race	1 Participants n=5 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants

PRIMARY outcome

Timeframe: 1 hour

Outcome measures

Outcome measures
Measure	Item n=32 Participants Memory for item recognition	Context n=32 Participants Memory for spatial location of item
Memory Performance Parietal, before TMS	0.89 proportion accuracy Standard Deviation 0.01	0.64 proportion accuracy Standard Deviation 0.03
Memory Performance Parietal, during TMS	0.91 proportion accuracy Standard Deviation 0.01	0.66 proportion accuracy Standard Deviation 0.03
Memory Performance Vertex, before TMS	0.92 proportion accuracy Standard Deviation 0.01	0.69 proportion accuracy Standard Deviation 0.02
Memory Performance Vertex, during TMS	0.89 proportion accuracy Standard Deviation 0.01	0.66 proportion accuracy Standard Deviation 0.03

PRIMARY outcome

Timeframe: During encoding (with TMS) and during retrieval (after TMS)

Population: Due to EEG trigger issues, only 14 subjects were able to complete the retrieval arm and have data analyzed as ERPs.

Participants completed a memory task with simultaneous EEG acquisition and transcranial magnetic stimulation (TMS) delivered to either a memory-relevant parietal lobe target or a vertex control site. Participants were shown a series of objects in one of four quadrants on the screen, with TMS delivered either prior to or concurrent with the trial onset. They were instructed to remember the object and the location. This outcome measure examines the neural response to trials which were later remembered relative to trials which were later forgotten. Values represent the difference in average EEG amplitude, in uV, between remembered and forgotten trials and compared across each stimulation condition (parietal or vertex location, before or during the trial)

Outcome measures

Outcome measures
Measure	Item n=32 Participants Memory for item recognition	Context n=14 Participants Memory for spatial location of item
Late Positive Posterior (ERP) Event Related Potential Parietal, before TMS	1.49 uV Standard Deviation 0.83	-0.11 uV Standard Deviation 1.47
Late Positive Posterior (ERP) Event Related Potential Parietal, during TMS	1.43 uV Standard Deviation 0.63	1.29 uV Standard Deviation 1.88
Late Positive Posterior (ERP) Event Related Potential Vertex, before TMS	0.96 uV Standard Deviation 0.76	-0.91 uV Standard Deviation 1.35
Late Positive Posterior (ERP) Event Related Potential Vertex, during TMS	-1.07 uV Standard Deviation 1.41	0.79 uV Standard Deviation 2.16

SECONDARY outcome

Timeframe: During encoding (with TMS) and during retrieval (after TMS)

Population: Due to EEG trigger issues, only 14 subjects had retrieval data analyzed as task-evoked power

Participants completed a memory task with simultaneous EEG acquisition and transcranial magnetic stimulation (TMS) delivered to either a memory-relevant parietal lobe target or a vertex control site. Participants were shown a series of objects in one of four quadrants on the screen, with TMS delivered either prior to or concurrent with the trial onset. They were instructed to remember the object and the location. This outcome measure examines the neural response to trials which were later remembered relative to trials which were later forgotten. Values represent the difference in average task-evoked power in the theta/alpha range (4-13Hz), in uV, between remembered and forgotten trials and compared across each stimulation condition (parietal or vertex location, before or during the trial)

Outcome measures

Outcome measures
Measure	Item n=32 Participants Memory for item recognition	Context n=14 Participants Memory for spatial location of item
Theta/Alpha Power Vertex, before trial TMS	2.25 uV Standard Deviation 5.04	0.18 uV Standard Deviation 0.50
Theta/Alpha Power Vertex, during trial TMS	1.07 uV Standard Deviation 3.50	-0.06 uV Standard Deviation 0.56
Theta/Alpha Power Parietal, before trial TMS	1.46 uV Standard Deviation 2.29	-0.18 uV Standard Deviation 0.56
Theta/Alpha Power Parietal during trial TMS	0.94 uV Standard Deviation 3.20	0.06 uV Standard Deviation 0.46

Adverse Events

Healthy Participants

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

Dr. Eric Wassermann

National Institutes of Health

Phone: 301-496-0151

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place