Healthy Adult, Stroke
Conditions
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.
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.
Interventions
PROCEDUREUnilateral Left tVNS stimulation
Electrical stimulation to the cymba concha and tragus of the outer ear on the left side.
PROCEDUREBilateral tVNS stimulation
Electrical stimulation to the cymba concha and tragus of the outer ear on both sides.
PROCEDUREUnilateral Left Sham stimulation
Electrical stimulation to the earlobe of the outer ear on the left side.
PROCEDUREBilateral Sham stimulation
Electrical stimulation to the earlobe of the outer ear on both sides.
PROCEDUREUnilateral Right tVNS stimulation
Electrical stimulation to the cymba concha and tragus of the outer ear on the right side.
PROCEDUREUnilateral Right Sham stimulation
Electrical stimulation to the earlobe of the outer ear on the right side.
Sponsors
Georgia Institute of Technology
Emory University
Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE
Masking
NONE
Intervention 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.
Eligibility
Sex/Gender
ALL
Age
18 Years to 89 Years
Healthy volunteers
Yes
Inclusion criteria
* 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.
Exclusion criteria
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 * 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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Peak Percent Change in Pupil Diameter During Stimulation | 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 | 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. |
Countries
United States
Contacts
PRINCIPAL_INVESTIGATORMinoru Shinohara, Ph.D.
Georgia Institute of Technology
Baseline characteristics
| Characteristic | — |
|---|---|
| Age, Continuous | 42.1 Years STANDARD_DEVIATION 21.1 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 1 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 20 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants |
| Race (NIH/OMB) Asian | 7 Participants |
| Race (NIH/OMB) Black or African American | 4 Participants |
| Race (NIH/OMB) More than one race | 1 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants |
| Race (NIH/OMB) White | 9 Participants |
| Sex: Female, Male Female | 5 Participants |
| Sex: Female, Male Male | 16 Participants |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | 0 / 21 |
| other Total, other adverse events | 0 / 21 |
| serious Total, serious adverse events | 0 / 21 |
Outcome results
None listed