Microelectrode Recordings From the Vagus Nerve in Awake Humans

Epilepsy Clinical Trial

Official title:

Microelectrode Recordings From the Vagus Nerve in Awake Humans

Clinical Trial Details — Status: Recruiting

Administrative data

• NCT number: NCT06016686
• Other study ID #: VNS
• Status: Recruiting
• Phase: Phase 1
• Start date: April 1, 2024
• Est. completion date: April 1, 2025

Study information

• Verified date: May 2024
• Source: University of Minnesota
• Contact: Kathryn Vera, PhD
• Phone: 612-625-5018
• Email: giero002[@]umn.edu
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

This Anchillary project uses a refined technique of ultrasound-guided microneurography of the human cervical vagus nerve, an approach developed by Professor Vaughan Macefield and used safely to-date in 44 prior study participants.

The overall goal of this project is to build upon prior data obtained using this approach by undertaking a detailed neurophysiological investigation of the human vagus nerve and to identify the nerve fibers activated during vagal nerve stimulation (VNS) in participants with implanted VNS devices in response to different stimulation parameters. In addition to providing data in unprecedented detail into the physiology of the human vagus nerve, this project will investigate different stimulus intensities, durations and frequencies that differentially excite myelinated and unmyelinated nerve fibers. These results will inform the CSP and guide future development of novel neural interfaces for VNS for various clinical applications.

Recruitment information / eligibility

• Status: Recruiting
• Enrollment: 60
• Est. completion date: April 1, 2025
• Est. primary completion date: April 1, 2025
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years to 40 Years

Eligibility

Inclusion Criteria:

• The participant is greater than or equal to (=)18 years and is less than or equal to (=) 40 years of age

• English speaking

• Medicare covered or equivalent health insurance from a partner country

Exclusion Criteria:

• Pregnant

• Smokes and is unwilling to abstain from smoking on the day of the experiment.

• Inability or unwillingness to provide written informed consent.

• Individuals with difficulty standing unassisted for 5 minutes during the tilt-table testing

• Individuals found to have a significant carotid artery plaque or intima-media thickness > 1 mm as assessed by ultrasonography during the ultrasound-screening steps of the study visit

• Vagus nerve not visible on ultrasound

• VNS electrodes are not in a suitable location to allow for microelectrode insertion

• Any other clinical reasons deemed by the investigators

Related Conditions & MeSH terms

• Epilepsy

Intervention

Other:
• VNS stimulation and intraneural recordings
A minimum of three stimulation frequencies (1, 10 and 30 Hz), each up to 60s in duration, will be delivered via the VNS device. Intraneural recordings proximal or distal to the VNS electrodes during delivery of VNS will be performed. Approximately two to five fascicles will be explored in each nerve.
• Record multi-unit activity from intraneural sites
Perform a more detailed vagal nerve mapping study by recording from single nerve fibers, including those fibers supplying the heart, lungs, airways and other end-organs. The investigators shall perform functional mapping of the left and right vagus nerves, such as those with cardiac-related and/or respiratory-related neural activity. The research team will also record activity from other nearby fibers to map the differences in neurological behavior in fascicles that control the heart, lungs, airways and other systems.

Locations

Country	Name	City	State
Australia	99 Commercial Road	Prahan Victoria
United States	University of Minnesota	Minneapolis	Minnesota

Sponsors (1)

Lead Sponsor	Collaborator
University of Minnesota

Countries where clinical trial is conducted

United States,  Australia, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	identify action potential morphology of specific fibers activated by vagal nerve stimulation (VNS)	assessing vagal nerve activity in epilepsy participants during and in the absence of stimulation. Labchart; spike histogram module	4 hours
Primary	identify ratio of myelinated fibers in specific fibers activated by vagal nerve stimulation (VNS)	assessing vagal nerve activity in epilepsy participants during and in the absence of stimulation. Labchart; spike histogram module. Whether a nerve fiber is (un)myelinated can be determined by visual inspection. Myelinated fibers typically produce "a positive-going narrow spike profile.	4 hours
Primary	physiological identification of the specific fibers activated by vagal nerve stimulation (VNS)	assessing vagal nerve activity in epilepsy participants during and in the absence of stimulation. Labchart; spike histogram module. use of tracing and nerve recordings analysis to identify the types of nerves	4 hours
Primary	identify firing rates of the specific fibers activated by vagal nerve stimulation (VNS)	assessing vagal nerve activity in epilepsy participants during and in the absence of stimulation. Labchart; spike histogram module. in Hertz	4 hours
Primary	identify stimulus current required to activate specific fibers activated by vagal nerve stimulation (VNS)	assessing vagal nerve activity in epilepsy participants during and in the absence of stimulation. Labchart; spike histogram module. in milli-amps	4 hours
Primary	differences in firing rates of cardiac parasympathetic vagal activity	compare any changes in parasympathetic vagal activity with participants who have not been implanted with a vagal nerve stimulator (Non-VNS Participants).; Labchart; spike histogram module. Unit: Hz.	4 hours
Primary	Discharge variability of cardiac parasympathetic nerve fibers	Vagal nerve stimulator device. Coefficient of variation, %	4 hours