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

Not Applicable

Completed

• Conditions: Fibromyalgia (FM); Chronic Pain

• Registration Number: NCT07173400
• Lead Sponsor: Hatice Betigul Meral

Brief Summary

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).

Detailed 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.

Study Timeline

• Study Start: 2025-01-10
• Primary Completion: 2025-06-20
• Study Completion: 2025-06-25
• Status Verified: 2025-09
• Study First Submitted: 2025-09-05
• Study First Submitted QC: 2025-09-12
• Last Update Submitted: 2025-09-12
• Study First Posted: 2025-09-15
• Last Update Posted: 2025-09-15

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 30

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

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Fibromyalgia Impact Questionnaire (FIQ)	Baseline, Week 2, Week 4, Week 8	The FIQ evaluates the overall health status and functional impact of fibromyalgia, including physical functioning, pain, fatigue, and mood. Scores range from 0 to 100, with higher scores reflecting greater disease impact.
Pittsburgh Sleep Quality Index (PSQI)	Baseline, Week 2, Week 4, Week 8	The PSQI is a validated self-report questionnaire that assesses subjective sleep quality and disturbances over the past month. Scores range from 0 to 21, with higher scores indicating poorer sleep quality.
Central Sensitization Inventory (CSI)	Baseline, Week 2, Week 4, Week 8	The CSI is a 25-item self-report questionnaire assessing symptoms related to central sensitization, including sensitivity to pain, fatigue, and cognitive complaints. Scores range from 0 to 100, with higher scores indicating greater sensitization.

Secondary Outcome Measures

Name	Time	Method
Tampa Scale for Kinesiophobia (TSK)	Baseline, Week 2, Week 4, Week 8	The TSK is a 17-item self-report questionnaire measuring fear of movement or reinjury. Items are scored on a 4-point Likert scale, with total scores ranging from 17 to 68. Higher scores indicate greater kinesiophobia.
Visual Analog Scale (VAS) for Pain	Baseline, Week 2, Week 4, Week 8	Pain intensity is assessed using a 10-cm visual analog scale, with 0 representing "no pain" and 10 representing "worst imaginable pain." Participants mark their pain level along the line, which is recorded as a numeric score.

Trial Locations

Locations (1)

Istanbul Medipol University, Faculty of Medicine, Department of Physical Medicine and Rehabilitation; Istanbul, Bagcılar, Turkey (Türkiye)