Influence of Transcranial Direct Current Stimulation of the Primary Motor Cortex on Pain Sensation in Patients Suffering From Fibromyalgia Syndrome

Inclusion Criteria: * Patients who have an established diagnosis of fibromyalgia according to the 1990 criteria of the "American College of Rheumatology" * Symptoms have been present at a similar level for at least 3 months * Stable medication for at least 2 months * visual analog scale ≥ 3 (0=no pain; 10=worst possible pain) * The patient does not have a disorder that would otherwise explain the pain Exclusion Criteria: * Alcohol/substance abuse * Pregnancy * Neuropsychiatric disorders * Metal implants near stimulation area * Cardiac pace maker * Local injuries * Inflammatory rheumatic disease * Acute tumor * Acute fracture * Well-defined neuropathic induced pain