Trial Outcomes & Findings for Examining Transcutaneous Vagal Nerve Stimulation as a Facilitator of Social Bonding (NCT NCT05899413)

NCT ID: NCT05899413

Last Updated: 2025-05-04

Results Overview

RSA was assessed continuously throughout the conversation.

Recruitment status

COMPLETED

Target enrollment

160 participants

Primary outcome timeframe

Continuously throughout conflict conversation

Results posted on

2025-05-04

Participant Flow

A total of 80 couples (i.e., 160 participants) were recruited from February 2024.

Couples were randomly assigned to either the active or sham stimulation condition after confirming their eligibility and completing a background questionnaire at home. Although all sessions were completed, technical issues (e.g., tVNS device malfunction) occurred in some cases. When this happened, the affected couple was excluded from the random assignment, and the next couple was reassigned to that condition.

Participant milestones

Participant milestones
Measure	Active tVNS We delivered stimulation at the individually calibrated intensity continuously during the interactions, and the default device settings we adopted were as follows: frequency = 30Hz, phase duration = 250μs, interphase interval = 50μs, and max voltage = 65V. In the active stimulation condition, both partners will have the stimulation clip attached to the outer auditory canal. In the sham stimulation condition, they will have the stimulation clip attached to their earlobe.	Sham tVNS In the sham condition, both partners will have electrodes attached to the center of the left ear lobe. They will still receive stimulation but at a placement that should not activate the vagus nerve.
Overall Study STARTED	86	74
Overall Study COMPLETED	86	74
Overall Study NOT COMPLETED	0	0

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Examining Transcutaneous Vagal Nerve Stimulation as a Facilitator of Social Bonding

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Active tVNS n=63 Participants We delivered stimulation at the individually calibrated intensity continuously during the interactions, and the default device settings we adopted were as follows: frequency = 30Hz, phase duration = 250μs, interphase interval = 50μs, and max voltage = 65V. In the active stimulation condition, both partners will have the stimulation clip attached to the outer auditory canal.	Sham tVNS n=71 Participants In the sham condition, both partners will have electrodes attached to the center of the left ear lobe. They will still receive stimulation but at a placement that should not activate the vagus nerve.	Total n=134 Participants Total of all reporting groups
Age, Continuous	28.17 years STANDARD_DEVIATION 4.33 • n=5 Participants	27.65 years STANDARD_DEVIATION 4.26 • n=7 Participants	27.90 years STANDARD_DEVIATION 4.29 • n=5 Participants
Sex/Gender, Customized Female/Male/Other · Female	30 Participants n=5 Participants	34 Participants n=7 Participants	64 Participants n=5 Participants
Sex/Gender, Customized Female/Male/Other · Male	32 Participants n=5 Participants	34 Participants n=7 Participants	66 Participants n=5 Participants
Sex/Gender, Customized Female/Male/Other · Other	1 Participants n=5 Participants	3 Participants n=7 Participants	4 Participants n=5 Participants
Race (NIH/OMB) American Indian or Alaska Native	1 Participants n=5 Participants	2 Participants n=7 Participants	3 Participants n=5 Participants
Race (NIH/OMB) Asian	27 Participants n=5 Participants	35 Participants n=7 Participants	62 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	0 Participants n=5 Participants	3 Participants n=7 Participants	3 Participants n=5 Participants
Race (NIH/OMB) White	33 Participants n=5 Participants	23 Participants n=7 Participants	56 Participants n=5 Participants
Race (NIH/OMB) More than one race	1 Participants n=5 Participants	4 Participants n=7 Participants	5 Participants n=5 Participants
Race (NIH/OMB) Unknown or Not Reported	1 Participants n=5 Participants	4 Participants n=7 Participants	5 Participants n=5 Participants
Relationship duration	4.23 Years STANDARD_DEVIATION 3.06 • n=5 Participants	4.41 Years STANDARD_DEVIATION 2.41 • n=7 Participants	4.33 Years STANDARD_DEVIATION 2.73 • n=5 Participants

PRIMARY outcome

Timeframe: Once, self-reported in a survey immediately following conflict interaction, up to 10 minutes

Population: Our analysis included 134 participants with complete physiological and self-report data. Missing data resulted from session failures (e.g., unstable or missing physiological measurements) or survey non-response

During the conversation, overall, I felt… (1: not at all positive, 7: extremely positive)

Outcome measures

Outcome measures
Measure	Active tVNS n=63 Participants We delivered stimulation at the individually calibrated intensity continuously during the interactions, and the default device settings we adopted were as follows: frequency = 30Hz, phase duration = 250μs, interphase interval = 50μs, and max voltage = 65V. In the active stimulation condition, both partners will have the stimulation clip attached to the outer auditory canal.	Sham tVNS n=71 Participants In the sham condition, both partners will have electrodes attached to the center of the left ear lobe. They will still receive stimulation but at a placement that should not activate the vagus nerve.
Self-reported Positive Affect	5.89 units on a scale Standard Deviation 0.92	5.69 units on a scale Standard Deviation 1.15

PRIMARY outcome

Timeframe: Once, self-reported in a survey immediately following conflict interaction, up to 10 minutes

During the conversation, overall, I felt… (1: not at all negative, 7: extremely negative)

Outcome measures

Outcome measures
Measure	Active tVNS n=63 Participants We delivered stimulation at the individually calibrated intensity continuously during the interactions, and the default device settings we adopted were as follows: frequency = 30Hz, phase duration = 250μs, interphase interval = 50μs, and max voltage = 65V. In the active stimulation condition, both partners will have the stimulation clip attached to the outer auditory canal.	Sham tVNS n=71 Participants In the sham condition, both partners will have electrodes attached to the center of the left ear lobe. They will still receive stimulation but at a placement that should not activate the vagus nerve.
Self-reported Negative Affect	5.79 units on a scale Standard Deviation 1.18	5.62 units on a scale Standard Deviation 1.32

PRIMARY outcome

Timeframe: Continuously throughout conflict conversation

RSA was assessed continuously throughout the conversation.

Outcome measures

Outcome measures
Measure	Active tVNS n=63 Participants We delivered stimulation at the individually calibrated intensity continuously during the interactions, and the default device settings we adopted were as follows: frequency = 30Hz, phase duration = 250μs, interphase interval = 50μs, and max voltage = 65V. In the active stimulation condition, both partners will have the stimulation clip attached to the outer auditory canal.	Sham tVNS n=71 Participants In the sham condition, both partners will have electrodes attached to the center of the left ear lobe. They will still receive stimulation but at a placement that should not activate the vagus nerve.
Respiratory Sinus Arrhythmia	6.47 ms Standard Error 0.74	6.54 ms Standard Error 0.89

PRIMARY outcome

Timeframe: Continuously throughout the conflict conversation

IBI was assessed continuously throughout the conversation.

Outcome measures

Outcome measures
Measure	Active tVNS n=63 Participants We delivered stimulation at the individually calibrated intensity continuously during the interactions, and the default device settings we adopted were as follows: frequency = 30Hz, phase duration = 250μs, interphase interval = 50μs, and max voltage = 65V. In the active stimulation condition, both partners will have the stimulation clip attached to the outer auditory canal.	Sham tVNS n=71 Participants In the sham condition, both partners will have electrodes attached to the center of the left ear lobe. They will still receive stimulation but at a placement that should not activate the vagus nerve.
Interbeat Interval	793.71 ms Standard Deviation 101.74	808.20 ms Standard Deviation 100.63

Adverse Events

Active tVNS

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Sham tVNS

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. Yoobin Park

University of California, San Francisco

Phone: 6289461325

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place