Effects of Transcutaneous Auricular Vagus Nerve Stimulation on Symptom Severity, Sleep Quality, Central Sensitization, and Kinesiophobia in Fibromyalgia

Hatice Betigul Meral

Status: Completed

Conditions: Fibromyalgia (FM); Chronic Pain

Treatments: Device: Active Transcutaneous Auricular Vagus Nerve Stimulation (TaVNS); Device: Sham Transcutaneous Auricular Vagus Nerve Stimulation

Study type: Interventional

Funder types: Other

Identifiers

NCT07173400

E-10840098-202.3.02-4945 (30/0

Details and patient eligibility

About

Fibromyalgia is a chronic condition characterized by widespread musculoskeletal pain, fatigue, sleep disturbances, and sensitivity to touch. Current treatments often provide only partial relief. This study evaluates a non-invasive technique called transcutaneous auricular vagus nerve stimulation (TaVNS), which delivers gentle electrical impulses to a part of the ear connected to the vagus nerve. The vagus nerve plays an important role in regulating pain, stress, and autonomic body functions such as sleep.

In this randomized controlled pilot trial, participants with fibromyalgia are assigned to receive either active TaVNS or sham (placebo) stimulation for 30 minutes per day, five days per week, over a four-week period. Participants are followed for a total of 8 weeks. The investigators will assess outcomes including pain intensity, sleep quality, central sensitization, and fear of movement (kinesiophobia).

Full description

Fibromyalgia (FM) is a chronic pain syndrome associated with widespread musculoskeletal pain, fatigue, sleep disturbances, and autonomic dysregulation. Current treatments provide only partial relief, highlighting the need for novel therapeutic approaches.

Rationale:

The vagus nerve is a key regulator of autonomic and inflammatory processes. Transcutaneous auricular vagus nerve stimulation (TaVNS) is a non-invasive technique that can modulate vagal activity through electrodes placed on the external ear, offering a potential alternative to surgically implanted vagus nerve stimulators.

Study Design:

This is a randomized, sham-controlled pilot trial conducted at Istanbul Medipol University. Thirty participants with fibromyalgia are randomized in a 1:1 ratio to receive either active TaVNS or sham stimulation.

Intervention:

Device: VagusStim® (Vagus Medical Technologies, Istanbul, Türkiye; CE-marked).

Electrode placement: left cymba concha (active group) vs. left earlobe (sham group).

Stimulation parameters: frequency 1-30 Hz, pulse width 50-250 μs, current intensity individually adjusted (0.1-36 mA) to each participant's sensory threshold.

Schedule: 30 minutes per day, 5 days per week, for 4 consecutive weeks (20 sessions total).

Supervision: All sessions are clinician-supervised.

Outcome Measures:

Primary outcomes:

Pittsburgh Sleep Quality Index (PSQI) - subjective sleep quality.

Fibromyalgia Impact Questionnaire (FIQ) - disease severity and functional impact.

Central Sensitization Inventory (CSI) - symptoms related to central sensitization.

Secondary outcomes:

Visual Analog Scale (VAS) - pain intensity.

Tampa Scale for Kinesiophobia (TSK) - fear of movement.

Symptom Severity Scale (SSS).

Widespread Pain Index (WPI).

Assessment timepoints: baseline, week 2, week 4, and week 8.

Enrollment: 30 patients

Sex: All

Ages: 18 to 65 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

Age between 18 and 65 years

Diagnosis of fibromyalgia according to the 2016 revised ACR criteria

Receiving stable pharmacological and/or non-pharmacological treatment for at least 3 months

Ability to understand study procedures and provide informed consent

Exclusion criteria

Pregnancy

History of epilepsy or cardiac arrhythmia

Acute or chronic infection

Heart failure (NYHA class II-IV)

Renal failure stage II or higher

Active malignancy

Psychotic disorders or current psychiatric treatment

Diagnosis of immune-mediated rheumatic disease

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Single Blind

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30 participants in 2 patient groups, including a placebo group

Active TaVNS

Experimental group

Description:

Participants received active transcutaneous auricular vagus nerve stimulation (TaVNS) using the VagusStim® device (Vagus Medical Technologies, Istanbul, Türkiye). The electrode was placed on the left cymba concha and stimulation was applied for 30 minutes per day, 5 days per week, over 4 weeks (20 sessions). Stimulation parameters included 1-30 Hz frequency, 50-250 μs pulse width, and current individually adjusted (0.1-36 mA) to each participant's sensory threshold.

Treatment:

Device: Active Transcutaneous Auricular Vagus Nerve Stimulation (TaVNS)

Sham TaVNS

Placebo Comparator group

Description:

Participants underwent sham stimulation using the same VagusStim® device under identical conditions. The electrode was placed on the left earlobe, an area without vagal innervation, and sessions lasted 30 minutes per day, 5 days per week, for 4 weeks. No effective vagus nerve stimulation was delivered, maintaining participant blinding.

Treatment:

Device: Sham Transcutaneous Auricular Vagus Nerve Stimulation