Transcutaneous Vagus Nerve Stimulation on Fibromyalgia- Double-blind, Sham-controlled Randomized Clinical Trial

Stimulation of the vagus nerve, a parasympathetic nerve that controls the digestive, the vascular and immune systems, produces pain relief in various clinical conditions. Transmission via vagal afferents to the nucleus of the solitary tract has been proposed as the primary physiological mechanism that reduces pain intensity following vagal stimulation. Medication is one of the pillars of dealing with chronic pain, with several benefits, but also side effects. Fibromyalgia is an idiopathic chronic pain syndrome with few, effective and safe treatments. However, current research in the field of vagal innervation suggests psychophysiological and electrical ways by which the syndrome may be treated.The chronic pain symptoms of fibromyalgia patients may benefit from vagus nerve stimulation, by normalizing the autonomic and immune system dysfunction that causes their respective symptoms. However, the effects of multiple sessions of transcutaneous vagus nerve stimulation (tVNS) in fibromyalgia have not been evaluated in randomized clinical trials. The hypothesis of our study is to evaluate if the addition of transcutaneous stimulation of the auricular branch of the vagus nerves in patients with fibromyalgia, can lead to better pain control and quality of life. We will offer a 2-week treatment (14 sessions of 30 minutes) in a randomized double-blind controlled trial. The sample of the study, which will be conducted in the pain clinic of the Aretaieion University General Hospital, will be consisted of 120 patients, who will be divided into 2 groups (1st group: standard pharmacological treatment + active tVNS, 2nd group: standard pharmacological treatment + sham tVNS). The study is designed to determine, if standard pharmacological treatment combined with 14 sessions of tVNS is able to improve pain symptomatology in fibromyalgia and all symptoms of this syndrome, by using appropriate scales. This study examines a new and potentially impactful way to address a major public health issue where prevalence is high in given groups, its impact is multidimensional and treatment options are limited. The holistic treatment of chronic pain, including its neurobiological, cognitive, behavioral and psychological components, may become a valuable aid in the completion of the research project, with the ultimate aim of the study being the establishment of non-invasive stimulation of the vagus nerve for the treatment of chronic pain in clinical practice in the future.