Fibromyalgia (FM), Chronic Pain
Conditions
Keywords
Vagal Nerve Stimulation, fibromyalgia, pain, chronic pain
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.
Interventions
Active TaVNS delivered with the VagusStim® device (Vagus Medical Technologies, Istanbul, Türkiye). The bipolar electrode was placed on the left cymba concha. Stimulation was applied for 30 minutes per day, 5 days per week, for 4 weeks (20 sessions). Parameters included frequency 1-30 Hz, pulse width 50-250 μs, and current intensity individually adjusted (0.1-36 mA) to the participant's sensory threshold.
Sham stimulation delivered with the same VagusStim® device under identical conditions. The electrode was rotated and placed on the left earlobe, which lacks vagal innervation. Sessions lasted 30 minutes per day, 5 days per week, for 4 weeks (20 sessions). No effective vagus nerve stimulation was delivered, preserving participant blinding.
Sponsors
Hatice Betigul Meral
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Subject)
Masking description
Participants and outcome assessors were blinded to group allocation. The treating clinician who applied stimulation was aware of assignment but did not participate in outcome assessment
Intervention model description
This study used a two-arm, randomized, sham-controlled, parallel group design with a 1:1 allocation ratio
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
No
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| 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
| Measure | Time frame | Description |
|---|---|---|
| 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. |
Countries
Turkey (Türkiye)
Outcome results
None listed