StrokeNCT06335199

tVNS Responsiveness Testing With Pupil Size

A study testing Unilateral Left tVNS stimulation, Bilateral tVNS stimulation and Unilateral Right tVNS stimulation in people with Stroke and Healthy Adult, run by Georgia Institute of Technology at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial summary

Who is it for?: Ages 18 to 89 yearsHealthy volunteers can take part
Conditions the study is for: Stroke, Healthy Adult
What is being tested?: Unilateral Left tVNS stimulation, Bilateral tVNS stimulation and Unilateral Right tVNS stimulation
Type of treatment: Surgery or procedure
Could I receive a placebo?: Yes, some participants may receive a placebo
How many people: 21 participants
Where: 1 siteUnited States
Study dates: 14 Nov 2024to 27 Oct 2025
Phase: Interventional
Are there results?: Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 18 to 89 years
All sexes
Healthy volunteers accepted
Adult, Older adult

Who may be able to join

18-89 years old across all races, genders, and ethnicities.
Post-stroke subjects will have persistent hemiparesis on the upper extremity (UE) with some residual UE voluntary movement.

Who cannot join

Able-bodied subjects:
Younger than 18 years old or older than 89 years old
Current or history of cardiac disease
Have a vision problem not corrected by glasses or contact lenses
Have an implanted device such as a neurostimulator or cochlear implant
Current or history of tympanic membrane perforation

Show all 40Show fewer

Had a stroke or lesion (including tumor) in your brain
Had a head injury or brain surgery
Suffer from frequent or severe headaches
Had a fainting spell or syncope
Have any metal in the head such as shrapnel, surgical clips, or fragments from welding or metal work
Have any implanted device such as cardiac pacemakers, medical pumps, or intra-cardiac lines
Had any brain-related conditions (i.e. multiple sclerosis, Parkinson, Alzheimer)
Had any illness that caused brain injury (i.e. meningitis, aneurysm, brain tumor)
Had any head trauma that was associated with a loss of consciousness or diagnosed as a concussion
Being treated for any psychiatric condition (i.e. depression, anxiety, PTSD, schizophrenia)
Suspected of pregnancy
Post-stroke subjects:
Younger than 18 years old or older than 89 years old
Current or history of cardiac disease
Have a vision problem not corrected by glasses or contact lenses
Have any implanted devices such as a neurostimulator or cochlear implant
Current or history of tympanic membrane perforation
No persistent hemiparesis on the upper extremity (UE)
No residual UE voluntary movement
A first stroke less than 4 months prior to the participation
Serious uncontrolled medical conditions
Excessive pain in any joint of the more affected extremity
Unable to stand independently for 2 min., transfer independently to and from the toilet or perform sit-to-stand
Suffer from frequent or severe headaches
Had a fainting spell or syncope
Have any metal in the head such as shrapnel, surgical clips, or fragments from welding or metal work
Have any implanted device such as cardiac pacemakers, medical pumps, or intra-cardiac lines
Had any illness that caused brain injury (i.e. meningitis, aneurysm, brain tumor)
Had any head trauma that was associated with a loss of consciousness or diagnosed as a concussion
Being treated for any psychiatric condition (i.e. depression, anxiety, PTSD, schizophrenia)
Suspected of pregnancy
A score of less than 24 on the Folstein Mini-Mental State Examination
Excessive frailty or lack of stamina (e.g., cannot attend to instructions, stay awake, engage in functional activities, etc.)
Excessive pain in any joint of the more affected extremity that could limit ability to cooperate with the intervention

Trial locations and contacts

1 site in 1 country.

United States1 site

Human Neuromuscular Physiology Lab
Atlanta, Georgia, 30318

Other trials in United States

About this study

Official title: Movement-Associated tVNS and Responsiveness Testing for Personalized Rehabilitation

The goal of this study is to learn about the acute pupil response to transcutaneous vagus nerve stimulation (tVNS) in stroke survivors and healthy adults. The main question it aims to answer is whether pupil size response is greater with bilateral tVNS compared to unilateral tVNS. Participants will receive tVNS and sham at the outer ear unilaterally and bilaterally in resting condition. The pupil size of the participants will be recorded during tVNS.

Read the detailed description

Participants will wear surface electrodes on the outer ear on both sides and a finger device that monitors heart rate. The attachment sites are the tragus or the cymba concha (depending on the shape and size of the ear) for tVNS and the ear lobe for sham. The electrical current will have a pulse duration of 0.1 ms at 30 Hz with an intensity below the pain threshold or 5 milliamp, whichever is lower, for a duration of 0.5 s. The experimental stimulation intensity will be determined as just below the pain threshold. Participants will receive multiple blocks of unilateral left, unilateral right, and bilateral stimulations to the sham or tVNS electrodes at rest, during which their pupil size will be recorded. The order of unilateral/bilateral and sham/tVNS stimulation will be randomized.

Conditions: Stroke, Healthy Adult
Being tested: Unilateral Left tVNS stimulation, Bilateral tVNS stimulation, Unilateral Left Sham stimulation, Bilateral Sham stimulation, Unilateral Right tVNS stimulation
Medical subject headings: Stroke

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Unilateral Left tVNS stimulationProcedure or surgery
Electrical stimulation to the cymba concha and tragus of the outer ear on the left side.
Bilateral tVNS stimulationProcedure or surgery
Electrical stimulation to the cymba concha and tragus of the outer ear on both sides.
Unilateral Left Sham stimulationProcedure or surgery
Electrical stimulation to the earlobe of the outer ear on the left side.
Bilateral Sham stimulationProcedure or surgery
Electrical stimulation to the earlobe of the outer ear on both sides.
Unilateral Right tVNS stimulationProcedure or surgery
Electrical stimulation to the cymba concha and tragus of the outer ear on the right side.
Unilateral Right Sham stimulationProcedure or surgery
Electrical stimulation to the earlobe of the outer ear on the right side.

Study groups in NCT06335199
Study group	Role	What they receive
Repeated-Measures Stimulation Protocol	Experimental	All participants receive all six stimulation conditions: unilateral left sham, unilateral right sham, bilateral sham, unilateral left transcutaneous vagus nerve stimulation (tVNS), unilateral right tVNS, and bilateral tVNS. Each participant completes 12 blocks during a single testing session, with each block containing one trial of each of the six stimulation conditions. Twelve blocks with different predefined orders of the six conditions were established before testing began. For each participant, the order of the 12 predefined blocks is randomized. Thus, each participant receives each of the six stimulation conditions once per block and 12 times in total. Receives: Procedure: Unilateral Left tVNS stimulation; Procedure: Bilateral tVNS stimulation; Procedure: Unilateral Left Sham stimulation; Procedure: Bilateral Sham stimulation; Procedure: Unilateral Right tVNS stimulation; Procedure: Unilateral Right Sham stimulation

What is being measured

The primary outcome is the main question the study is designed to answer.

Peak Percent Change in Pupil Diameter During Stimulation
For each stimulation trial, pupil diameter is recorded continuously. The outcome is the maximum percent change in pupil diameter during the stimulation period relative to the mean pupil diameter measured immediately before stimulation within the same trial.
Measured: During one study visit (within 1 day)
Mean Percent Change in Pupil Diameter During Stimulation
For each stimulation trial, pupil diameter is recorded continuously. The outcome is the mean percent change in pupil diameter during the stimulation period relative to the mean pupil diameter measured immediately before stimulation within the same trial.
Measured: During one study visit (within 1 day)

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

14 Nov 202427 Oct 2025

First posted28 Mar 2024
Study start14 Nov 2024
Primary completion27 Oct 2025
Study completion27 Oct 2025

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Other trials for StrokeStudies of the same condition, open and under way.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Interventional
Phase: Phase N/A
Primary purpose: Basic science
Allocation: Not applicable
Intervention model: Single group
Model description: All participants receive all six stimulation conditions in a randomized order. The six conditions are unilateral left sham, unilateral right sham, bilateral sham, unilateral left transcutaneous vagus nerve stimulation (tVNS), unilateral right tVNS, and bilateral tVNS. The order of the six conditions is randomized independently for each participant.
Masking: None (open label)
Enrolment: 21 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT06335199
Sponsor's protocol ID: H24109
Other IDs: 5P2CHD086844-09
Status last verified: Mar 2025
First submitted: 15 Mar 2024
Last updated: 14 Sep 2026
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: No
FDA-regulated drug: No
FDA-regulated device: No
Individual data sharing: Yes: De-identified individual participant data on pupil size change will be available to other researchers outside the primary research group.

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

See locations

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All Stroke trials

Study at a glance

From the registry record, last updated by the sponsor on 14 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Movement-Associated tVNS and Responsiveness Testing for Personalized Rehabilitation
ClinicalTrials.gov ID: NCT06335199
Acronym / sponsor ID: H24109
Conditions: Stroke, Healthy Adult
Study type: Interventional
Recruitment status: Completed
Enrolment: 21 participants (actual)
Lead sponsor: Georgia Institute of TechnologyUniversity, hospital or other
Collaborators: Emory University, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
Study start: 14 Nov 2024 (actual)
Primary completion: 27 Oct 2025 (actual)
Study completion: 27 Oct 2025 (actual)
First posted: 28 Mar 2024 (actual)
Results: Posted 14 Sep 2026

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Detailed description

Study design

Primary purpose: Basic science
Allocation: Not applicable
Intervention model: Single group
Masking: None (open label)
Number of arms: 1
Model description: All participants receive all six stimulation conditions in a randomized order. The six conditions are unilateral left sham, unilateral right sham, bilateral sham, unilateral left transcutaneous vagus nerve stimulation (tVNS), unilateral right tVNS, and bilateral tVNS. The order of the six conditions is randomized independently for each participant.

Arm	Type	Receives
Repeated-Measures Stimulation Protocol	Experimental	Procedure: Unilateral Left tVNS stimulation, Procedure: Bilateral tVNS stimulation, Procedure: Unilateral Left Sham stimulation, Procedure: Bilateral Sham stimulation, Procedure: Unilateral Right tVNS stimulation, Procedure: Unilateral Right Sham stimulationAll participants receive all six stimulation conditions: unilateral left sham, unilateral right sham, bilateral sham, unilateral left transcutaneous vagus nerve stimulation (tVNS), unilateral right tVNS, and bilateral tVNS. Each participant completes 12 blocks during a single testing session, with each block containing one trial of each of the six stimulation conditions. Twelve blocks with different predefined orders of the six conditions were established before testing began. For each participant, the order of the 12 predefined blocks is randomized. Thus, each participant receives each of the six stimulation conditions once per block and 12 times in total.

Who may qualify

Ages: 18 to 89 years
Sex: All
Healthy volunteers: Accepted
Age groups: Adult, Older adult

Key inclusion criteria (2 listed)

18-89 years old across all races, genders, and ethnicities.
Post-stroke subjects will have persistent hemiparesis on the upper extremity (UE) with some residual UE voluntary movement.

Key exclusion criteria (40 listed)

Younger than 18 years old or older than 89 years old
Current or history of cardiac disease
Have a vision problem not corrected by glasses or contact lenses
Have an implanted device such as a neurostimulator or cochlear implant
Current or history of tympanic membrane perforation

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
Unilateral Left tVNS stimulationElectrical stimulation to the cymba concha and tragus of the outer ear on the left side.	Procedure or surgery	Repeated-Measures Stimulation Protocol
Bilateral tVNS stimulationElectrical stimulation to the cymba concha and tragus of the outer ear on both sides.	Procedure or surgery	Repeated-Measures Stimulation Protocol
Unilateral Left Sham stimulationElectrical stimulation to the earlobe of the outer ear on the left side.	Procedure or surgery	Repeated-Measures Stimulation Protocol
Bilateral Sham stimulationElectrical stimulation to the earlobe of the outer ear on both sides.	Procedure or surgery	Repeated-Measures Stimulation Protocol
Unilateral Right tVNS stimulationElectrical stimulation to the cymba concha and tragus of the outer ear on the right side.	Procedure or surgery	Repeated-Measures Stimulation Protocol
Unilateral Right Sham stimulationElectrical stimulation to the earlobe of the outer ear on the right side.	Procedure or surgery	Repeated-Measures Stimulation Protocol

Primary outcome

Peak Percent Change in Pupil Diameter During Stimulation
Time frame: During one study visit (within 1 day)
For each stimulation trial, pupil diameter is recorded continuously. The outcome is the maximum percent change in pupil diameter during the stimulation period relative to the mean pupil diameter measured immediately before stimulation within the same trial.
Mean Percent Change in Pupil Diameter During Stimulation
Time frame: During one study visit (within 1 day)
For each stimulation trial, pupil diameter is recorded continuously. The outcome is the mean percent change in pupil diameter during the stimulation period relative to the mean pupil diameter measured immediately before stimulation within the same trial.

Results and safety

Results posted to the registry on 14 Sep 2026, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Repeated-Measures Stimulation Protocol	21	20

Primary outcome: Peak Percent Change in Pupil Diameter During Stimulation

Time frame: During one study visit (within 1 day). Mean (Standard Deviation). Unit: Percent change

Measure	Randomized 2×3 Factorial Crossover n = 20
Unilateral left tVNS	7.799 (5.06)
Unilateral right tVNS	8.635 (4.124)
Bilateral tVNS	10.519 (4.979)
Unilateral left sham	4.200 (2.535)
Unilateral right sham	5.788 (2.579)
Bilateral sham	5.943 (2.777)

Randomized 2×3 Factorial Crossover: F statistic: 31.5, p = 0.000021, ANOVA
Randomized 2×3 Factorial Crossover: F statistic: 13.7, p = 0.000034, ANOVA
Randomized 2×3 Factorial Crossover: F statistic: 1.9, p = 0.167, ANOVA

Population analysed: The number of participants in this analysis (20) is fewer than the enrollment (21) because pupil data were not collected from one participant due to technical difficulties.

Primary outcome: Mean Percent Change in Pupil Diameter During Stimulation

Time frame: During one study visit (within 1 day). Mean (Standard Deviation). Unit: Percent change

Measure	Randomized 2×3 Factorial Crossover n = 20
Unilateral left tVNS	6.192 (3.868)
Unilateral right tVNS	6.726 (3.065)
Bilateral tVNS	8.223 (3.751)
Unilateral left sham	3.346 (1.995)
Unilateral right sham	4.591 (1.928)
Bilateral sham	4.790 (2.150)

Randomized 2×3 Factorial Crossover: F statistic: 32.0, p = 0.000019, ANOVA
Randomized 2×3 Factorial Crossover: F statistic: 16.3, p = 0.000008, ANOVA
Randomized 2×3 Factorial Crossover: F statistic: 1.7, p = 0.192, ANOVA

Population analysed: The number of participants in this analysis (20) is fewer than the enrollment (21) because pupil data were not collected from one participant due to technical difficulties.

Adverse events

Time frame: From enrollment to the end of the experiment, up to 1 day. Other adverse events reported at 0% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Randomized 2×3 Factorial Crossover	0 of 21 (0%)	0 of 21 (0%)	0 of 21

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 14 Sep 2026.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Individual participant dataSharing planned: Yes. De-identified individual participant data on pupil size change will be available to other researchers outside the primary research group.

Related trials for Stroke

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Closed-Loop SCS-BCI for Post-Stroke Hemiplegia
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Transferring Speed of Processing Gains to Everyday Cognitive Tasks After Stroke
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Not yet recruitingObservational study
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Not yet recruiting
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Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

Minoru Shinohara, Ph.D. principal investigator

Georgia Institute of Technology

1 site in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 2 inclusion and 40 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 14 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

Yes. Results are posted in the registry (first posted 14 Sep 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Peak Percent Change in Pupil Diameter During Stimulation (time frame: During one study visit (within 1 day)). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT06335199.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 14 Sep 2026.