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Systematic Evaluation of VNS Parameters

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
 
ClinicalTrials.gov Identifier: NCT05395026
Recruitment Status : Enrolling by invitation
First Posted : May 27, 2022
Last Update Posted : December 6, 2022
Sponsor:
Information provided by (Responsible Party):
Duke University

Study Description
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Brief Summary:
The goal of this study is to measure the activation of the vagus nerve and the side effects of vagus nerve stimulation (VNS) (neck muscle contractions, changes in heart rate) across a range of stimulation parameters typically used in VNS therapy for epilepsy (pulse durations, pulse amplitudes, pulse repetition rates). This mapping of the parameter space may inform future device programming to improve electrical activation of the vagus nerve and/or to reduce side effects, and it may be used for validation of computational models. The study will recruit adult participants with epilepsy who are undergoing surgery either for an initial implant of a VNS device or for replacement of the implanted pulse generator (IPG) due to battery depletion. During surgery, the study will involve stimulating the vagus nerve via the standard implanted clinical VNS electrodes over a range of stimulation parameters while recording the activity of the vagus nerve (electroneurogram (ENG)), electromyogram (EMG) response of neck/throat muscles, and the heart rate (electrocardiogram (EKG)). Stimulation parameters will be within the ranges used for clinical therapy and below limits established for non-damaging electrical stimulation.

Condition or disease Intervention/treatment Phase
Epilepsy Other: electrical stimulation of vagus nerve Not Applicable

Detailed Description:

This study will recruit adult participants with epilepsy who are undergoing planned surgery either for an initial implant of a vagus nerve stimulation (VNS) device or for replacement of their VNS implanted pulse generator (IPG) due to battery depletion. The primary study goals are to measure the activation of the vagus nerve and the side effects of vagus nerve stimulation (neck muscle contractions, changes in heart rate) across a range of stimulation parameters typically used in VNS therapy for epilepsy. This mapping of the parameter space may inform future device programming to improve electrical activation of the vagus nerve and/or to reduce side effects. All study participants will be assigned to a single study group and will complete the same study procedures.

The research study will take place during VNS surgery. For participants undergoing a first VNS implant surgery, once the vagus nerve is exposed and before placing the VNS electrodes, the investigators may image the nerve with ultrasound. Mapping of the parameter space will then occur after placement of the cuff electrodes around the cervical vagus nerve for participants undergoing a first VNS implant surgery or removal of the IPG with the depleted battery for patients undergoing IPG replacement surgery. Temporary sterile extension wires will connect the implanted VNS electrode to the research stimulation system. Research procedures will involve stimulating the vagus nerve through the standard implanted clinical VNS electrodes over a range of stimulation parameters. At the same time, the investigators will record how changes in stimulation affect the activity of the vagus nerve (measured by electroneurogram (ENG)), the response of the neck and throat muscles (by electromyogram (EMG)) and the heart rate (by electrocardiogram (EKG)). Several stimulation trials will be conducted with different VNS parameters (pulse duration, pulse amplitude, and pulse repetition rate) delivered in randomized order. Stimulation parameters will be within the ranges used for clinical therapy and will not exceed those that produce a 25% reduction in heart rate. Measurements will be made during 10 to 60 second trials, in which stimulation will be off for the first section (baseline), on for the second section (responses to stimulation), and off for the final section (recovery). The stimulus waveform will be a charge-balanced biphasic pulse, with values of charge density (D) limited to values below the nondamaging limits that are well-established in literature.

Study Design
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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 18 participants
Allocation: N/A
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Basic Science
Official Title: Systematic Evaluation of Vagus Nerve Stimulation Parameters on Cardiac Rhythm, Laryngeal Muscle Electromyography, and Vagus Nerve Activation in Acute and Chronic Implantations
Actual Study Start Date : November 28, 2022
Estimated Primary Completion Date : April 30, 2024
Estimated Study Completion Date : April 30, 2024

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Epilepsy

Arms and Interventions
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Arm Intervention/treatment
Experimental: Investigational Stimulation Parameters Other: electrical stimulation of vagus nerve
VNS electrical stimulation parameters (pulse duration, pulse amplitude, and pulse frequency) will be systematically changed to determine the effect on vagus nerve activation, laryngeal muscle contraction, and heart rate.


Outcome Measures
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Primary Outcome Measures :
  1. stimulation amplitude threshold [ Time Frame: During procedure (30 minutes) ]
    The stimulation amplitude threshold is the amplitude when vagus nerve stimulation (VNS) activates the laryngeal muscles and has potential to cause subject discomfort during stimulation. The stimulation amplitude threshold will be measured with the NIM-EMG endotracheal tube recording, and the threshold will be determined as the amplitude that causes the first evoked potential in the laryngeal muscles.


Eligibility Criteria
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Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.


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Ages Eligible for Study:   18 Years to 65 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  • adult epilepsy patients undergoing VNS electrode implantation or implanted pulse generator (IPG) replacement surgery
  • in good health
  • neurologically stable aside from epilepsy
  • able to provide informed consent

Exclusion Criteria:

  • patients with another implanted electrical device (besides VNS)
  • a history of heart conditions that the surgeon considers a contraindication to study participation
Contacts and Locations
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Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT05395026


Locations
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United States, North Carolina
Duke University Medical Center
Durham, North Carolina, United States, 27710
Sponsors and Collaborators
Duke University
Investigators
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Principal Investigator: Warren M Grill, PhD Duke University
More Information
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Publications:

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Responsible Party: Duke University
ClinicalTrials.gov Identifier: NCT05395026    
Other Study ID Numbers: Pro00103473
First Posted: May 27, 2022    Key Record Dates
Last Update Posted: December 6, 2022
Last Verified: December 2022
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Additional relevant MeSH terms:
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Epilepsy
Brain Diseases
Central Nervous System Diseases
Nervous System Diseases