NCT06335199

Brief Summary

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.

Trial Health

87
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
21

participants targeted

Target at below P25 for not_applicable stroke

Timeline
Completed

Started Nov 2024

Geographic Reach
1 country

1 active site

Status
completed

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

First Submitted

Initial submission to the registry

March 15, 2024

Completed
13 days until next milestone

First Posted

Study publicly available on registry

March 28, 2024

Completed
8 months until next milestone

Study Start

First participant enrolled

November 14, 2024

Completed
12 months until next milestone

Primary Completion

Last participant's last visit for primary outcome

October 27, 2025

Completed
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

October 27, 2025

Completed
Last Updated

October 29, 2025

Status Verified

March 1, 2025

Enrollment Period

12 months

First QC Date

March 15, 2024

Last Update Submit

October 28, 2025

Conditions

Outcome Measures

Primary Outcomes (1)

  • Pupil size change

    Acute change in pupil size in response to electrical stimulation, relatively expressed as a percent change from the baseline

    Day 1

Study Arms (6)

Unilateral Left tVNS

EXPERIMENTAL

Electrical stimulation to the vagus nerve area of the outer ear on the left side.

Procedure: Unilateral Left tVNS stimulation

Bilateral tVNS

EXPERIMENTAL

Electrical stimulation to the vagus nerve area of the outer ear on both sides.

Procedure: Bilateral tVNS stimulation

Unilateral Left Sham

SHAM COMPARATOR

Electrical stimulation to the non-vagus nerve area of the outer ear on the left side.

Procedure: Unilateral Left Sham stimulation

Bilateral Sham

SHAM COMPARATOR

Electrical stimulation to the non-vagus nerve area of the outer ear on both sides.

Procedure: Bilateral Sham stimulation

Unilateral Right tVNS

EXPERIMENTAL

Electrical stimulation to the vagus nerve area of the outer ear on the right side.

Procedure: Unilateral Right tVNS stimulation

Unilateral Right Sham

SHAM COMPARATOR

Electrical stimulation to the non-vagus nerve area of the outer ear on the right side.

Procedure: Unilateral Right Sham stimulation

Interventions

Electrical stimulation to the cymba concha or tragus (depending on the ear dimension) of the outer ear on the left side after successful trials.

Unilateral Left tVNS

Electrical stimulation to the cymba concha or tragus (depending on the ear dimension) of the outer ear on both sides after successful trials.

Bilateral tVNS

Electrical stimulation to the earlobe of the outer ear on the left side after successful trials.

Unilateral Left Sham

Electrical stimulation to the earlobe of the outer ear on both sides after successful trials.

Bilateral Sham

Electrical stimulation to the cymba concha or tragus (depending on the ear dimension) of the outer ear on the right side after successful trials.

Unilateral Right tVNS

Electrical stimulation to the earlobe of the outer ear on the right side after successful trials.

Unilateral Right Sham

Eligibility Criteria

Age18 Years - 89 Years
Sexall
Healthy VolunteersYes
Age GroupsAdult (18-64), Older Adult (65+)

You may qualify if:

  • 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.

You may not qualify if:

  • 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
  • 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
  • +25 more criteria

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Human Neuromuscular Physiology Lab

Atlanta, Georgia, 30318, United States

Location

MeSH Terms

Conditions

Stroke

Condition Hierarchy (Ancestors)

Cerebrovascular DisordersBrain DiseasesCentral Nervous System DiseasesNervous System DiseasesVascular DiseasesCardiovascular Diseases

Study Officials

  • Minoru Shinohara, Ph.D.

    Georgia Institute of Technology

    PRINCIPAL INVESTIGATOR

Study Design

Study Type
interventional
Phase
not applicable
Allocation
RANDOMIZED
Masking
DOUBLE
Who Masked
PARTICIPANT, OUTCOMES ASSESSOR
Purpose
BASIC SCIENCE
Intervention Model
SINGLE GROUP
Sponsor Type
OTHER
Responsible Party
SPONSOR

Study Record Dates

First Submitted

March 15, 2024

First Posted

March 28, 2024

Study Start

November 14, 2024

Primary Completion

October 27, 2025

Study Completion

October 27, 2025

Last Updated

October 29, 2025

Record last verified: 2025-03

Data Sharing

IPD Sharing
Will share

De-identified individual participant data on pupil size change will be available to other researchers outside the primary research group.

Shared Documents
STUDY PROTOCOL, SAP, ICF
Time Frame
The data will become available after the publication of all papers from the study.
Access Criteria
The scientific data will be made available by a data repository after approval.

Locations