Effects of Vagus Nerve Stimulation on Central Pain Sensitivity & Parasympathetic Function in Knee Osteoarthritis

NCT ID: NCT05625178

Last Updated: 2025-04-02

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 30 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2022-12-15
• Study Completion Date: 2023-06-08

Brief Summary

The goal of this clinical trial is to test the feasibility and effectiveness of transcutaneous vagus nerve stimulation (tVNS) to the ear on pain and autonomic function in people with knee osteoarthritis (OA). The main questions it aims to answer are: 1) whether tVNS is feasible to be used in people with knee OA; 2) whether tVNS demonstrates the trend in improving knee pain; and 3) whether tVNS has physiological effects on autonomic function (e.g., parasympathetic function) and pain perception in the central nervous system such as brain (i.e., central pain mechanisms). Participants will be asked to complete a battery of self-reported questionnaires about their demographic and behavioral information, ethnicity, pain, sleep, psychological/emotional symptoms. Subsequently, participants will complete baseline assessment where investigators will assess their knee pain severity, central pain sensitivity, and heart rate variability (a measurement for autonomic function). Then participants will receive a 60-minute tVNS. Investigators will redo the same assessment as baseline assessment after tVNS intervention to see the degree of knee pain, central pain sensitivity, and autonomic function changes. At the end of the study, investigators will assess their satisfaction level with the tVNS intervention and the feasibility of the intervention (e.g., completion rate, side effects).

Conditions

Knee Osteoarthritis; Central Pain Syndrome

Study Design

• Allocation Method: NA
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: TREATMENT
• Blinding Strategy: NONE

Study Groups

tVNS group

This will be a single-arm study where all study participants will receive transcutaneous vagus nerve stimulation (tVNS) at the cymba concha of the left ear for 60 minutes. The tVNS parameters will be a below-discomfort-threshold intensity with 25 Hz and a pulse width of 250 uS.

Group Type: EXPERIMENTAL

Transcutaneous vagus nerve stimulation

Intervention Type: DEVICE

tVNS will be performed by the application of an auricular electrode placed at the cymba concha of the left ear. The auricular electrode containing the anode will be applied with a conductive gel without prior disinfection. Once the electrode fits the cymba concha comfortably, the participant will lie down or take a position that is comfortable for them. Once in position, investigators initiate tVNS for 60 minutes with a below-discomfort-threshold intensity with 25 Hz and pulse width 250 uS. The electrical parameters will be modified accordingly to keep the below-discomfort threshold during the intervention.

Interventions

Transcutaneous vagus nerve stimulation

tVNS will be performed by the application of an auricular electrode placed at the cymba concha of the left ear. The auricular electrode containing the anode will be applied with a conductive gel without prior disinfection. Once the electrode fits the cymba concha comfortably, the participant will lie down or take a position that is comfortable for them. Once in position, investigators initiate tVNS for 60 minutes with a below-discomfort-threshold intensity with 25 Hz and pulse width 250 uS. The electrical parameters will be modified accordingly to keep the below-discomfort threshold during the intervention.

Intervention Type: DEVICE

Eligibility Criteria

Inclusion Criteria

• chronic knee pain consistent with a clinical osteoarthritis diagnosis, which does not require radiographic evidence (age ≥ 45 years, activity-related knee pain, and no knee morning stiffness lasting >30 minutes)
• knee pain ≥ 3 months
• average pain intensity ≥ 4 on a scale from 0 to 10
• knee pain as the chief complaint
• able to understand English

Exclusion Criteria

• current skin disease of the left ear interfering with the application of the auricular electrode for stimulation(eczema, urticarial lesion, skin infection, external otitis, etc.)
• auditory canal not adapted to the application of the ear electrode
• known history of cardiac rhythm disturbances or atrioventricular block > 1st degree, conduction disturbances
• recurrent vagal syncope
• history of vagotomy
• use of other medical devices electrically active (pacemaker, transcutaneous electrical nerve stimulation, etc)
• serious and uncontrolled concomitant disease, including cardiovascular, nervous system, pulmonary, renal, hepatic, endocrine, gastrointestinal, epileptic disease or malignant diseases
• pregnant or breastfeeding woman
• numbness or sensation loss on the body sites for pain measurements (i.e., the wrist, knee, the forearm)
• any intervention procedures for knee pain in the past 3 months
• age less than 45 years old

• Minimum Eligible Age: 45 Years
• Maximum Eligible Age: 90 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

University of Texas, El Paso

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Locations

University of Texas at El Paso

El Paso, Texas, United States

Countries

United States

References

Aoyagi K, Rivas E, Shababi R, Edwards R, LaValley M, Lechuga J, Napadow V, Neogi T. Safety and preliminary efficacy of transcutaneous auricular vagus nerve stimulation on chronic knee pain: A pilot trial. Osteoarthr Cartil Open. 2024 Nov 23;7(1):100545. doi: 10.1016/j.ocarto.2024.100545. eCollection 2025 Mar.

Reference Type: DERIVED

PMID: 39687279 (View on PubMed)

Other Identifiers

1966880-1

Identifier Type: -

Identifier Source: org_study_id