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

The University of Texas System (UT)

Status: Completed

Conditions: Central Pain Syndrome; Knee Osteoarthritis

Treatments: Device: Transcutaneous vagus nerve stimulation

Study type: Interventional

Funder types: Other

Identifiers

NCT05625178

1966880-1

Details and patient eligibility

About

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).

Enrollment: 30 patients

Sex: All

Ages: 45 to 90 years old

Volunteers: No Healthy Volunteers

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

Trial design

Primary purpose: Treatment

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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30 participants in 1 patient group

tVNS group

Experimental group

Description:

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.

Treatment:

Device: Transcutaneous vagus nerve stimulation