Transcutaneous Auricular Vagus Nerve Stimulation as a Treatment for Neuropathic Pain Following Spinal Cord Injury

NCT07588711 | Not Yet Recruiting

• 1 other identifier: ALLISON-03-2026
• Study Type: interventional
• Target: 32
• Locations: 1 country
• Sites: 1

Brief Summary

This pilot randomized, double-blind, sham-controlled clinical investigation will evaluate the feasibility and safety of a 30-day home-based transcutaneous auricular vagus nerve stimulation (taVNS) intervention in adults with spinal cord injury (SCI) and neuropathic pain. Participants will be randomized to receive either active taVNS targeting the auricular branch of the vagus nerve or sham taVNS delivered to the earlobe. Primary outcomes include feasibility, safety, adherence, acceptability, and blinding success. Exploratory outcomes include changes in neuropathic pain, systemic inflammatory biomarkers, vagal tone assessed via heart rate variability, and quality of life.

Conditions

Spinal Cord Injury; Neuropathic Pain

Keywords

vagus nerve stimulation; inflammation; spinal cord injury; neuropathic pain; taVNS

Outcome Measures

Primary Outcomes (6)

• Recruitment Rate and Time to Recruit Target Sample Size

  Recruitment feasibility will be assessed by documenting the number and proportion of eligible individuals who consent to participate and the total time required to recruit the target sample of 32 participants. Recruitment rate will be calculated as the percentage of eligible candidates who agree to participate. These data will be summarized descriptively for the overall study population.

  Up to 20 months

• Retention and Attrition During the 30-Day Intervention

  Retention will be assessed as the proportion of enrolled participants who complete the full 30-day intervention and post-intervention assessment. Attrition will be recorded as the number and proportion of participants who withdraw prior to study completion. Reasons for withdrawal or loss to follow-up will be documented where available. Retention and attrition rates will be summarized and compared descriptively between the active taVNS and sham taVNS groups.

  30 days

• Adherence to Daily taVNS Stimulation Prescription

  Adherence will be assessed using automated usage data recorded by the taVNS device and associated smartphone application. Daily adherence will be calculated as the percentage of the prescribed 4-hour daily stimulation period completed (actual stimulation time divided by prescribed stimulation time × 100). Overall adherence will be summarized as the mean daily adherence across the 30-day intervention period. Adherence will be compared descriptively between the active taVNS and sham taVNS groups.

  30 days

• Acceptability with the taVNS intervention

  Participant acceptability will be assessed at the end of the intervention using the Acceptability of Intervention Measure (AIM). Acceptability scores will be summarized descriptively and compared between the active taVNS and sham taVNS conditions.

  Day 30

• Incidence of Treatment-Emergent Adverse Events During Intervention

  All adverse events which occur during the intervention will be recorded during the twice weekly phone calls and/or study visits and compared between the active taVNS and sham taVNS conditions. A description of the adverse event, number of events, and total number of participants affected will be recorded.

  30 days

• Success of Participant and Investigator Blinding

  Blinding success will be assessed after completion of the intervention by asking participants and investigators to indicate which treatment group they believe the participant was assigned to (active taVNS or sham taVNS). Blinding effectiveness will be quantified using the James Blinding Index, calculated separately for participants and investigators. Blinding outcomes will be summarized descriptively.

  Day 30

Secondary Outcomes (9)

• Change in Neuropathic Pain Assessed by the Neuropathic Pain Symptoms Inventory

  Baseline and Day 30

• Change in Neuropathic Pain Assessed by the International Spinal Cord Injury Pain Basic Data Set (version 3)

  Baseline and Day 30

• Change in Circulating C-Reactive Protein

  Baseline and Day 30

• Change in Circulating Interleukin-1 Beta

  Baseline and Day 30

• Change in Circulating Interleukin-6

  Baseline and Day 30

Study Arms (2)

Active taVNS

EXPERIMENTAL

Participants receive active transcutaneous auricular vagus nerve stimulation delivered via the cymba conchae of the left ear using the using the tVNS R device (taVNS Technologies, Erlangen, Germany) for 4 hours per day for 30 days.

Device: Active Transcutaneous Auricular Vagus Nerve Stimulation

Sham taVNS

SHAM COMPARATOR

Stimulation will target the ear lobe using the tVNS R device (taVNS Technologies, Erlangen, Germany) for 4 hours per day for 30 days. Stimulation will be applied to the ear lobe in order to ensure participant feel the stimulation while avoiding activation of the vagus nerve.

Device: Sham Transcutaneous Auricular Vagus Nerve Stimulation

Interventions

Active Transcutaneous Auricular Vagus Nerve Stimulation DEVICE

Stimulation will target the auricular branch of the vagus nerve by applying stimulation to the cymba conchae region of the ear using the tVNS R device (taVNS Technologies, Erlangen, Germany). To achieve adequate stimulation while avoiding unpleasant or painful sensations, the stimulation intensity will be gradually increased in increments of 0.1mA (milliamps) until the subjective pain threshold is reached, and then reduced to a stimulus intensity just below the individuals pain threshold (expected range based on prior studies 1 - 3.2mA). Pulse width will be set at 100μs (microseconds) and frequency will be set at 25Hz (Hertz). Parameters will be set for the duration of the intervention consisting of 4 hours of daily stimulation for a period of 30 days.

Active taVNS

Sham Transcutaneous Auricular Vagus Nerve Stimulation DEVICE

Stimulation will target the ear lobe using the tVNS R device (taVNS Technologies, Erlangen, Germany). To achieve adequate stimulation while avoiding unpleasant or painful sensations, the stimulation intensity will be gradually increased in increments of 0.1mA until the subjective pain threshold is reached, and then reduced to a stimulus intensity just below the individuals pain threshold (expected range based on prior studies 1 - 3.2mA). Pulse width will be set at 100μs and frequency will be set at 25Hz. Participants will perform 4 hours of stimulation per day for a period of 30 days. Stimulation will be applied to the ear lobe in order to ensure participant feel the stimulation while avoiding activation of the vagus nerve.

Sham taVNS

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• SCI of any level or severity
• years of age or older
• current neuropathic pain
• on no medications or on a stable prescribed dose (no change in prior 6-weeks) of anti-inflammatory, pain medications and/or depression medications

You may not qualify if:

• Prone to autonomic dysreflexia
• presence of cardiovascular disease
• pacemaker or other implanted electrical device
• cerebral shunts
• epilepsy
• pregnant or attempting to become pregnant
• current wound/infection
• unstable dose of prescribed anti-inflammatory, depression, or pain medications within past 6-weeks.

Sponsors & Collaborators

• London Health Sciences Centre Research Institute OR Lawson Research Institute of St. Joseph's: lead

Study Sites (1)

Parkwood Institute, St Joseph's Health Care London

London, Ontario, N6C0A7, Canada

Location

MeSH Terms

Conditions

Spinal Cord Injuries; Neuralgia; Inflammation

Condition Hierarchy (Ancestors)

Spinal Cord Diseases; Central Nervous System Diseases; Nervous System Diseases; Trauma, Nervous System; Wounds and Injuries; Peripheral Nervous System Diseases; Neuromuscular Diseases; Pain; Neurologic Manifestations; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Pathologic Processes

Central Study Contacts

David J Allison, PhD.

CONTACT

519 646 6100; David.Allison@sjhc.london.on.ca

Joy Jiang

CONTACT

519 646 6100; fjiang63@uwo.ca

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: This is a randomized, double-blind, sham-controlled, parallel-group pilot study. Thirty-two adults with spinal cord injury and neuropathic pain will be randomized in a 1:1 ratio to receive either active transcutaneous auricular vagus nerve stimulation (taVNS) or sham taVNS. Following a baseline visit for eligibility confirmation, outcome assessments, and device training, participants will complete a 30-day home-based intervention during which they will use the assigned stimulation device for 4 hours per day. Outcomes will be assessed at baseline and at the end of the 30-day intervention period. Participants, investigators, care providers, and outcome assessors will remain blinded to treatment allocation throughout the study.

Study Record Dates

• First Submitted: April 7, 2026
• First Posted: May 15, 2026
• Study Start (Estimated): October 1, 2026
• Primary Completion (Estimated): May 1, 2028
• Study Completion (Estimated): August 30, 2028
• Last Updated: May 15, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will not share

Locations

CA (1)