ClinicalTrials.gg
Enrolling by invitationNCT04534556Updated Jun 15, 2026

Wireless Nerve Stimulation Device To Enhance Recovery After Stroke

An interventional study of Active Vagus Nerve Stimulation and Placebo Vagus Nerve Stimulation in Stroke, Chronic Stroke and Upper Extremity Paresis, sponsored by Baylor Research Institute. Enrolling by invitation at 1 site in United States. Open to participants aged 22 Years to 79 Years. Per ClinicalTrials.gov, last updated 2026-06-15.

Sponsored by Baylor Research Institute · Not applicable, Interventional, and Device feasibility

Phase
Not applicable
Study type
Interventional
Enrollment
42
Allocation
Randomized
Ages
22 Years to 79 Years
Sex
All
01

Study summary

Texas Biomedical Device Center (TxBDC) has developed an innovative strategy to enhance recovery of motor and sensory function after neurological injury termed targeted plasticity therapy (TPT). This technique uses brief pulses of vagus nerve stimulation to engage pro-plasticity neuromodulatory circuits during rehabilitation exercises. Preclinical findings demonstrate that VNS paired with rehabilitative training enhances recovery in multiple models of neurological injury, including stroke, spinal cord injury, intracerebral hemorrhage, and traumatic brain injury. Recovery is associated with neural plasticity in spared motor networks in the brain and spinal cord. Moreover, two initial studies and a recently completed Phase 3 clinical trial using a commercially available device demonstrates that paired VNS with rehabilitation is safe and improves motor recovery after stroke. The purpose of this study is to extend these findings and evaluate whether VNS delivered with the new device paired with rehabilitation represents a safe and feasible strategy to improve recovery of motor and sensory function in participants with stroke.

02

Conditions studied

  • Stroke
  • Chronic Stroke
  • Upper Extremity Paresis
  • Ischemic Stroke
  • Hemorrhagic Stroke

Keywords

  • Vagus Nerve Stimulation (VNS)
  • Rehabilitation
  • Targeted Plasticity Therapy
03

In context

Stroke

8,255 studies on the registry are indexed under Stroke; 2,056 are open to participants now.

This study's planned enrollment of 42 is below the median of 49 across 6,024 interventional studies indexed under Stroke.

Browse Stroke studies →

Lead sponsor

Baylor Research Institute is the lead sponsor of 223 studies on the registry; 48 are open to participants now.

Of its 23 completed or terminated interventional studies of FDA-regulated products, 9 (39%) have results posted.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
22 Years to 79 Years
Sexes eligible
All
Accepts healthy volunteers
No

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

In order to be eligible to participate in this study, an individual must meet all of the following criteria:

  • Provision of signed and dated form
  • Stated willingness to comply with all study procedures and availability for the duration of the study
  • Adult, aged 22-79
  • Ischemic or hemorrhagic stroke that occurred ≥ 12 months prior to enrollment
  • UEFM score of 20 to 50
  • Modified Rankin Score of 2, 3, or 4
  • Right vocal cord has normal movement when assessed by laryngoscopy
  • Women of must use protection
  • Meets all clinical criteria for the surgical VNS implantation as determined by the PI, surgeon, and anesthesiologist

Exclusion criteria

Exclusion Criteria:

An individual who meets any of the following criteria will be excluded from participation in this study:

  • Deficits in language or attention that interfere with study participation
  • Severe spasticity (Modified Ashworth ≥ 3)
  • Medical or mental instability that would likely interfere with study protocol
  • Receiving any therapy (medication or otherwise) that would interfere with VNS, such as drugs that perturb neurotransmitter action (anticholinergics, adrenergic blockers, etc.)
  • Presence of any other implanted electrical stimulation device
  • Prior injury to vagus nerve
  • Lactating, pregnant, or plan to become pregnant
  • Participation in another interventional clinical trial
  • Clinical complications that hinder or contraindicate the surgical procedure
  • Abusive use of alcohol and/or illegal substances use
  • Participants with sickle cell, lupus, clotting disorders or active neoplastic disease.
  • Participants with any any medical condition or other circumstances that might interfere with their ability to return for follow-up visits in the judgment of the Investigator.
  • Any condition which, in the judgment of the Investigator, would preclude adequate evaluation of device's safety and performance.
  • Recent history of syncope
  • Recent history of dysphagia
  • Current or anticipated requirement for diathermy
  • Uncontrolled hypertension
  • Diagnosed with Cerebral amyloid angiopathy
Terms in these criteria, in plain language(3)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

Informed consent

Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.

You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.

Reproductive potential

Able to have children. For women this usually means from the first period until menopause, unless permanently unable to through surgery; for men, unless permanently sterile. Read who the line is about — participants, women, men, or their partners.

Criteria about it usually ask for contraception during the study and for a time after it.

Contraception

Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.

Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.

05

Study design

Phase
Not applicable
Primary purpose
Device feasibility
Allocation
Randomized
Intervention model
Crossover assignment
Masking
Triple (Participant, Care provider, Investigator)
Enrollment
42 participants (estimated)

Study arms

  • Experimental
    Immediate Start Vagus Nerve Stimulation group

    The Immediate Start VNS group will receive rehabilitation and active stimulation for 18 in-office sessions over the course of approximately six weeks during Phase 1. For Phase 2, all subjects will be provided with the option to participate in an open-label extension consisting of an additional 18 sessions of in-office rehabilitation with active VNS over the course of approximately six weeks. Additionally, participants may be provided with a system of rehabilitative devices to utilize at home.

    Device: Active Vagus Nerve Stimulation

  • Placebo comparator
    Delayed Start Vagus Nerve Stimulation group

    The Delayed Start VNS group will receive equivalent rehabilitation with placebo stimulation for 18 in-office sessions over the course of approximately six weeks during Phase 1. For Phase 2, all subjects will be provided with the option to participate in an open-label extension consisting of an additional 18 sessions of in-office rehabilitation with active VNS over the course of approximately six weeks. Additionally, participants may be provided with a system of rehabilitative devices to utilize at home.

    Device: Placebo Vagus Nerve Stimulation

  • Experimental
    Follow-On Study Group

    The Follow-On Study group will receive up to 112 rehabilitation sessions with active VNS over the course of approximately 36 weeks after completion of Phase II. Participants will be provided with a system of rehabilitative devices to utilize at home.

    Device: Active Vagus Nerve Stimulation

Interventions

  • DeviceActive Vagus Nerve Stimulation

    Stimulation of the vagus nerve that is paired with upper limb rehabilitation. VNS stimulation as described in the current study consists of 0.5 second trains of 0.8 mA; 100 µsec biphasic pulses at 30 Hz. Stimulation trains are delivered only during rehabilitation.

    Also known as: VNS, vagus nerve stimulation, paired VNS

  • DevicePlacebo Vagus Nerve Stimulation

    During Phase 1 of the study, the placebo group will receive a minimal amount of stimulation that fails to sufficiently activate the nerve, unknown to the participant and therapists. All participants will receive active stimulation during the Phase 2 open-label portion of the study.

    Also known as: placebo, control

06

What researchers measure

Primary outcomes

  1. Incidence of Adverse Events [Device Safety]

    Review of adverse events reported throughout the trial will be used to inform the potential risks associated with the ReStore system and provide a better understanding of risk/benefit analysis

    Time frame: From Week 1 through study follow-up, approximately two years after the implant date or final session of rehabilitation (whichever comes second)

Secondary outcomes

  1. ReStore Stimulation Successes

    The percentage of stimulation attempts classified as 'Success' from the total number of stimulation attempts made will be calculated for each participant and the mean percent of successful attempts across all participants will be used as the outcome measure.

    Time frame: Weeks 6-11, during follow-on intervention visits 2-13, 14-25, and 25-36

  2. Upper-Extremity Fugl-Meyer Assessment (UEFM)

    The UEFM Assessment is a sixty-six point assessment of mobility administered by a therapist designed to facilitate consistent collection and reporting of basic upper extremity findings. The endpoint will be: estimate the shift in UEFM assessment following active VNS

    Time frame: Weeks 1, 3, 10, 17

  3. Wolf Motor Task Functional Ability Scale

    The Wolf Motor Task Functional Ability Scale (WMFT-FAS) is a quantitative measure of upper extremity motor ability through timed and functional tasks. The task includes evaluation of dexterity, strength, and upper extremity function. Functional ability is measured on a 6-point ordinal scale (0-5) with a maximum total score of 75. The endpoint will be: estimate the shift in WMFT-FAS assessment following active VNS

    Time frame: Weeks 1, 3, 10, 17

  4. Action Research Arm Test

    The ARAT is a nineteen-item observational assessment of upper limb function. The areas of assessment include activities of daily living, coordination, dexterity, and upper extremity function. The endpoint will be: Estimate the shift in ARAT assessment following active VNS

    Time frame: Weeks 1, 5, 12, 19, 20, 24, 32

  5. Modified Rankin Scale

    The Modified Rankin Scale (MRS) is a single item global outcomes rating scale that categorizes level of functional independence. The measure reflects ability to perform activities of daily living and functional mobility. The MRS is a 6 point scale with 0 being no disability and 5 being severe disability. A score of 6 indicates that the patient has expired. The endpoint will be: Estimate the shift in MRS assessment following active VNS

    Time frame: Weeks 1, 5, 12, 19, 20, 24, 32

  6. Quantitative Force and Range of Motion Assessment

    The Quantitative Force and Range of Motion Assessment form is a physical assessment of upper limb changes in force/torque as a result of VNS paired rehabilitation. The endpoints will be: 10% increase in finger pinch and flexion force following active VNS; 10% increase in wrist flexion and extension force following active VNS; 10% increase in wrist pronation and supination force following active VNS

    Time frame: Weeks 1, 3, 10, 17

07

Study locations

1 site
08

References and documents

Publications

  • Engineer ND, Kimberley TJ, Prudente CN, Dawson J, Tarver WB, Hays SA. Targeted Vagus Nerve Stimulation for Rehabilitation After Stroke. Front Neurosci. 2019 Mar 29;13:280. doi: 10.3389/fnins.2019.00280. eCollection 2019. PubMed 30983963 ↗
  • Khodaparast N, Hays SA, Sloan AM, Hulsey DR, Ruiz A, Pantoja M, Rennaker RL 2nd, Kilgard MP. Vagus nerve stimulation during rehabilitative training improves forelimb strength following ischemic stroke. Neurobiol Dis. 2013 Dec;60:80-8. doi: 10.1016/j.nbd.2013.08.002. Epub 2013 Aug 15. PubMed 23954448 ↗
  • Khodaparast N, Hays SA, Sloan AM, Fayyaz T, Hulsey DR, Rennaker RL 2nd, Kilgard MP. Vagus nerve stimulation delivered during motor rehabilitation improves recovery in a rat model of stroke. Neurorehabil Neural Repair. 2014 Sep;28(7):698-706. doi: 10.1177/1545968314521006. Epub 2014 Feb 18. PubMed 24553102 ↗
  • Hays SA, Khodaparast N, Ruiz A, Sloan AM, Hulsey DR, Rennaker RL 2nd, Kilgard MP. The timing and amount of vagus nerve stimulation during rehabilitative training affect poststroke recovery of forelimb strength. Neuroreport. 2014 Jun 18;25(9):676-82. doi: 10.1097/WNR.0000000000000154. PubMed 24818637 ↗
  • Hays SA, Khodaparast N, Hulsey DR, Ruiz A, Sloan AM, Rennaker RL 2nd, Kilgard MP. Vagus nerve stimulation during rehabilitative training improves functional recovery after intracerebral hemorrhage. Stroke. 2014 Oct;45(10):3097-100. doi: 10.1161/STROKEAHA.114.006654. Epub 2014 Aug 21. PubMed 25147331 ↗
  • Hays SA, Ruiz A, Bethea T, Khodaparast N, Carmel JB, Rennaker RL 2nd, Kilgard MP. Vagus nerve stimulation during rehabilitative training enhances recovery of forelimb function after ischemic stroke in aged rats. Neurobiol Aging. 2016 Jul;43:111-8. doi: 10.1016/j.neurobiolaging.2016.03.030. Epub 2016 Apr 7. PubMed 27255820 ↗
  • Khodaparast N, Kilgard MP, Casavant R, Ruiz A, Qureshi I, Ganzer PD, Rennaker RL 2nd, Hays SA. Vagus Nerve Stimulation During Rehabilitative Training Improves Forelimb Recovery After Chronic Ischemic Stroke in Rats. Neurorehabil Neural Repair. 2016 Aug;30(7):676-84. doi: 10.1177/1545968315616494. Epub 2015 Nov 4. PubMed 26542082 ↗
  • Pruitt DT, Schmid AN, Kim LJ, Abe CM, Trieu JL, Choua C, Hays SA, Kilgard MP, Rennaker RL. Vagus Nerve Stimulation Delivered with Motor Training Enhances Recovery of Function after Traumatic Brain Injury. J Neurotrauma. 2016 May 1;33(9):871-9. doi: 10.1089/neu.2015.3972. Epub 2015 Aug 5. PubMed 26058501 ↗
  • Ganzer PD, Darrow MJ, Meyers EC, Solorzano BR, Ruiz AD, Robertson NM, Adcock KS, James JT, Jeong HS, Becker AM, Goldberg MP, Pruitt DT, Hays SA, Kilgard MP, Rennaker RL 2nd. Closed-loop neuromodulation restores network connectivity and motor control after spinal cord injury. Elife. 2018 Mar 13;7:e32058. doi: 10.7554/eLife.32058. PubMed 29533186 ↗
  • Meyers EC, Solorzano BR, James J, Ganzer PD, Lai ES, Rennaker RL 2nd, Kilgard MP, Hays SA. Vagus Nerve Stimulation Enhances Stable Plasticity and Generalization of Stroke Recovery. Stroke. 2018 Mar;49(3):710-717. doi: 10.1161/STROKEAHA.117.019202. Epub 2018 Jan 25. PubMed 29371435 ↗
  • Engineer ND, Riley JR, Seale JD, Vrana WA, Shetake JA, Sudanagunta SP, Borland MS, Kilgard MP. Reversing pathological neural activity using targeted plasticity. Nature. 2011 Feb 3;470(7332):101-4. doi: 10.1038/nature09656. Epub 2011 Jan 12. PubMed 21228773 ↗
  • Kimberley TJ, Pierce D, Prudente CN, Francisco GE, Yozbatiran N, Smith P, Tarver B, Engineer ND, Alexander Dickie D, Kline DK, Wigginton JG, Cramer SC, Dawson J. Vagus Nerve Stimulation Paired With Upper Limb Rehabilitation After Chronic Stroke. Stroke. 2018 Nov;49(11):2789-2792. doi: 10.1161/STROKEAHA.118.022279. PubMed 30355189 ↗
  • Dawson J, Pierce D, Dixit A, Kimberley TJ, Robertson M, Tarver B, Hilmi O, McLean J, Forbes K, Kilgard MP, Rennaker RL, Cramer SC, Walters M, Engineer N. Safety, Feasibility, and Efficacy of Vagus Nerve Stimulation Paired With Upper-Limb Rehabilitation After Ischemic Stroke. Stroke. 2016 Jan;47(1):143-50. doi: 10.1161/STROKEAHA.115.010477. Epub 2015 Dec 8. PubMed 26645257 ↗
  • Kilgard MP, Rennaker RL, Alexander J, Dawson J. Vagus nerve stimulation paired with tactile training improved sensory function in a chronic stroke patient. NeuroRehabilitation. 2018;42(2):159-165. doi: 10.3233/NRE-172273. PubMed 29562561 ↗
  • Darrow MJ, Mian TM, Torres M, Haider Z, Danaphongse T, Rennaker RL Jr, Kilgard MP, Hays SA. Restoration of Somatosensory Function by Pairing Vagus Nerve Stimulation with Tactile Rehabilitation. Ann Neurol. 2020 Feb;87(2):194-205. doi: 10.1002/ana.25664. Epub 2020 Jan 7. PubMed 31875975 ↗
  • Meyers EC, Kasliwal N, Solorzano BR, Lai E, Bendale G, Berry A, Ganzer PD, Romero-Ortega M, Rennaker RL 2nd, Kilgard MP, Hays SA. Enhancing plasticity in central networks improves motor and sensory recovery after nerve damage. Nat Commun. 2019 Dec 19;10(1):5782. doi: 10.1038/s41467-019-13695-0. PubMed 31857587 ↗
  • Darrow MJ, Torres M, Sosa MJ, Danaphongse TT, Haider Z, Rennaker RL, Kilgard MP, Hays SA. Vagus Nerve Stimulation Paired With Rehabilitative Training Enhances Motor Recovery After Bilateral Spinal Cord Injury to Cervical Forelimb Motor Pools. Neurorehabil Neural Repair. 2020 Mar;34(3):200-209. doi: 10.1177/1545968319895480. Epub 2020 Jan 22. PubMed 31969052 ↗
  • Heck C, Helmers SL, DeGiorgio CM. Vagus nerve stimulation therapy, epilepsy, and device parameters: scientific basis and recommendations for use. Neurology. 2002 Sep 24;59(6 Suppl 4):S31-7. doi: 10.1212/wnl.59.6_suppl_4.s31. PubMed 12270966 ↗
  • Agnew WF, McCreery DB, Yuen TG, Bullara LA. Histologic and physiologic evaluation of electrically stimulated peripheral nerve: considerations for the selection of parameters. Ann Biomed Eng. 1989;17(1):39-60. doi: 10.1007/BF02364272. PubMed 2537589 ↗
  • Hays SA, Adehunoluwa EA, Epperson JD, Malley KM, Porter AL, Gallaway HL, Swank C, Carrera AJ, Stevens C, Gillespie J, Arnold D, Kian S, Bynum ZS, Meyers EC, Bleker N, Naftalis RC, Foreman ML, Hamilton RG, Rennaker RL, Kilgard MP, Wigginton JG. Closed-Loop Vagus Nerve Stimulation Delivered With a Miniaturized System Produces Lasting Recovery in Individuals With Chronic Stroke. Stroke. 2026 Jan;57(1):38-49. doi: 10.1161/STROKEAHA.125.052937. Epub 2025 Oct 7. PubMed 41054846 ↗

Individual participant data

Plan to share: No

09

Timeline

Tracking since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reachedSimilar studies: half by the dot; the band is the middle halfHalf of similar studies reached it by the dot; the band is the middle half, from a quarter to three quarters

Started Sep 2021 (actual). Primary completion is estimated for Jan 2027, 63 months after the start.

Of 3,108 non-industry interventional studies with no phase under Stroke, half reached primary completion within 23 months of starting (the median), counting those still running; a quarter within 10 and three quarters within 46. This study's planned 63 months is above that.

Counting every sponsor, half of 3,252 studies reached it within 23 months; a quarter within 10 and three quarters within 46.

How these figures are worked out, and which studies are left out of them.

Registered
Aug 18, 2020
First posted
Sep 1, 2020
StartActual
Sep 24, 2021
Primary completionEst.
Jan 1, 2027
CompletionEst.
Jan 1, 2027
Last update
Jun 15, 2026
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on Jun 15, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT04534556
Responsible party
Sponsor
First posted
Sep 1, 2020
Start date
Sep 24, 2021
Primary completion
Jan 1, 2027 (estimated)
Completion
Jan 1, 2027 (estimated)
Last update
Jun 15, 2026

Study contacts

Michael Kilgard, PhD
principal investigator · The University of Texas at Dallas
Robert Rennaker, PhD
principal investigator · The University of Texas at Dallas
Seth Hays, PhD
study director · The University of Texas at Dallas
Jane Wigginton, MD
principal investigator · University of Texas Southwestern Medical Center
Rita Hamilton, DO
principal investigator · Baylor Scott & White Institute for Rehabilitation
Michael Foreman, MD, FACS
study director · Baylor Health Care System
Richard Naftalis, MD, FAANS, FACS
study director · Baylor Health Care System
Mark Powers, PhD
study director · Baylor Health Care System
Ann Marie Warren, PhD
study director · Baylor Health Care System

Oversight

Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
Yes
View the source record on ClinicalTrials.gov ↗

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