The Effect of Intermittent Theta Burst Stimulation to the Primary Motor Cortex on Pain Intensity, Pain Catastrophizing, Quality of Life and Mood in Fibromyalgia Patients

Fibromyalgia syndrome (FMS) is a chronic condition characterized by generalized body pain, fatigue, sleep disturbance, impaired cognitive function and anxiety of unknown etiology. Potential causes include genetic, neurologic, psychological, sleep and immunologic factors. In the literature, complaints or symptoms reported by more than 25% of patients with FMS include widespread body pain, fatigue, morning stiffness, headache, paresthesia, sleep disturbance, subjective swelling, dry mouth, irritable bowel, dysmenorrhea, joint hypermobility, temporomandibular joint dysfunction, dermographism, Raynaud's phenomenon and reticular skin discoloration. Although some factors are known to predispose individuals to FMS (e.g. genes, adverse life events and physical trauma), the etiology of FMS is still unknown.

One of the best-supported hypotheses regarding its pathophysiology is the presence of central sensitization to pain and deficiencies in endogenous pain inhibitory mechanisms. Its prevalence has been reported as 0.2% to 6.6%. This rate increases to 2.4% to 6.8% in women. This rate increases in the 40-60 age group and in Turkey, the prevalence of fibromyalgia is reported to be 3.6% in women, with the highest rate (10.1%) observed in women aged 50-59 years. Studies show that fibromyalgia is more common in the female gender, among people with low education and socioeconomic status, and in the 40-60 age group.

The clinical picture of the patients shows that the pain is usually localized at first, but then involves many muscle groups. Hyperalgesia and allodynia are important features of fibromyalgia, although it can often be described as burning, gnawing pain, stiffness or aching sensation. Patients often complain of swollen joints and paresthesia despite the absence of any objective clinical findings during physical examination. Pain is often exacerbated by cold and damp weather, inadequate sleep, physical and mental stress.

There is no gold standard for the diagnosis of fibromyalgia. There are no laboratory markers or tests for the diagnosis of FMS and the diagnosis is made entirely clinically. Although the 1990 and 2010 criteria were also used in the diagnosis of FMS until recently, the latest version of the 2016 American College of Rheumatology (ACR) revised criteria are used. According to the 2016 ACR diagnostic criteria, the presence of generalized pain defined as pain in at least four of the five regions (four quadrants and axial) (however, jaw, chest, abdomen, headache and facial pain should not be included in the quadrant or regional definition of generalized pain), symptoms should be present at a similar level for at least 3 months, and scores should be WPI ≥ 7 and SS ≥ 5 or WPI 4-6 and SS ≥ 9.

The main goal of treatment should be to alleviate the patient's symptoms and improve quality of life. Current evidence-based guidelines emphasize the value of multimodal therapies, including both non-pharmacological and selected pharmacological treatments tailored to individual symptoms, including pain, fatigue, sleep problems and mood problems.According to EULAR, in the treatment of fibromyalgia, non-pharmacological treatment should be the first-line treatment and, if there is a lack of efficacy, individualized treatment should be applied, which may include pharmacological treatment according to the patient's needs, and these recommendations are now firmly evidence-based. Through various interventions such as non-pharmacological treatment methods; cognitive-behavioral therapy (CBT), physical therapy, mindfulness, acupuncture, physical therapy and exercise, mindfulness and meditation, acupuncture and acupressure, individuals can develop effective strategies to cope with pain, improve their functional abilities and increase their quality of life. Exercise has been shown to reduce stress, depression and anxiety and has been successfully applied in the treatment of chronic pain disorders such as chronic pelvic pain, migraine and fibromyalgia. There are different mechanisms that may explain the beneficial effect of exercise on fibromyalgia, including causing an increase in endogenous opioids, stimulating brain structures involved in diminished analgesic pathways and/or maintaining the balance between excitatory (glutamate) and inhibitory (GABA) neurotransmitters in the brain. It has been shown that the greatest improvement in fibromyalgia patients is seen after prolonged (12 weeks) moderate intensity aerobic training. Another form of non-pharmacological treatment is Cognitive Behavioral Therapy, which involves educating patients about their pain, how to cope with their pain, such as relaxation training, and how to apply these cognitive coping techniques in real life situations. Among recent studies on fibromyalgia treatment, EEG-guided neurofeedback targeting specific brain regions such as the anterior cingulate cortex and supplementary motor area has shown initial success in alleviating chronic pain in fibromyalgia patients.