Transcutaneous Auricular Vagus Nerve Stimulation in Psoriatic Arthritis

Psoriatic arthritis (PsA) is a chronic, immune-mediated inflammatory disease characterized by heterogeneous clinical manifestations including peripheral arthritis, spondylitis, enthesitis, and dactylitis. Although currently available pharmacological therapies such as conventional synthetic disease-modifying antirheumatic drugs (DMARDs), biologic DMARDs, and targeted synthetic DMARDs are effective in many patients, treatment response may vary, and long-term use may be associated with adverse effects, infection risk, high cost, and treatment resistance. Recent neuroimmunology studies have demonstrated that the vagus nerve plays a significant role in modulation of inflammatory responses through the cholinergic anti-inflammatory pathway. Transcutaneous auricular vagus nerve stimulation (taVNS) is a non-invasive neuromodulation technique targeting the auricular branch of the vagus nerve and has emerged as a potentially safe and reproducible therapeutic approach in inflammatory disorders. Previous studies have shown that vagus nerve stimulation may reduce inflammatory cytokine production and improve clinical outcomes in diseases such as rheumatoid arthritis and systemic lupus erythematosus. However, evidence regarding the clinical and biological effects of taVNS in patients with psoriatic arthritis remains limited. The aim of this prospective, single-center, single-arm interventional study is to evaluate the effects of taVNS on disease activity, pain, functional status, quality of life, autonomic dysfunction symptoms, sleep quality, anxiety/depression symptoms, and inflammatory biomarkers including C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) in patients with PsA diagnosed according to the Classification Criteria for Psoriatic Arthritis (CASPAR). Eligible participants aged 18-65 years with moderate-to-severe disease activity will undergo non-invasive auricular vagus nerve stimulation using the Vagustim device. Electrodes will be placed on the tragus and cymba conchae regions of the auricle, and electrical stimulation will be applied for 20 minutes per session according to predefined stimulation parameters. Clinical assessments including the Disease Activity Index for Psoriatic Arthritis (DAPSA), Ankylosing Spondylitis Disease Activity Score based on C-reactive protein (ASDAS-CRP), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Visual Analog Scale (VAS) pain scores, the Short Form-12 Health Survey (SF-12), Pittsburgh Sleep Quality Index (PSQI), Composite Autonomic Symptom Score-31 (COMPASS-31), Hospital Anxiety and Depression Scale (HADS), and Fibromyalgia Rapid Screening Tool (FiRST) will be evaluated before and after treatment.