Home-based Transcranial Direct Current Stimulation in Fibromyalgia Patients

In this phase II, randomized, double-blind clinical trial, the investigators intended to evaluate the home-based effect of transcranial direct current stimulation (tDCS) in patients with fibromyalgia. This syndrome affects between 3-5% of the population in an age group 40-60 years also occurring in childhood and old age. Reaches 3.4% of women and 0.5% of men. Fibromyalgia is a chronic widespread pain syndrome in various parts of the body. The neuromodulation techniques have as a principle produce inhibition or cortical arousal. The tDCS is a non-invasive brain stimulation method used to modulate the cortical excitability, using a low intensity direct current (1-2mA) directed to the scalp via the cathode and anode electrodes. The current reaches the cortex, producing hyperpolarization or depolarization of the axonal membrane potential. Evidence has shown that this method is presented as a technique able to alter cortical and subcortical neural networks. This technique has been used to treat psychiatric disorders such as depression, acute mania, bipolar affective disorder, panic, hallucinations, obsessive compulsive disorder, schizophrenia, withdrawal, rehabilitation after stroke, pain syndromes such as neuropathic pain, migraine, pancreatitis pain chronic and fibromyalgia. The tDCS is a low cost technique, with virtually no side effects and which exerts therapeutic effect by neuromodulatory pathways by distinct pathways activated by the drugs. In this scenario falls within the importance of developing this device for home use by fibromyalgia patients, since it is easy to use and thereby enables maintaining the benefit observed in studies performed and supervised frequently used in care centers. The use of tDCS over the long term is not feasible in hospital by patients demands, sometimes every day or more than once a week, removing the patient from their activities, and cost shifting and overload the healthcare system. Therefore, the objective of this study is to evaluate the effect of home-based tDCS in fibromyalgia patients in long-term treatment.

Will be included women aged between 18 and 65 years, chronic pain fibromyalgia according to the criteria of the American College of Rheumatology, pain unresponsive to analgesics such as paracetamol, acetylsalicylic acid, ibuprofen, Carisoprodol, Zanaflex (Tizanidine) and Codeine. And give informed consent to participate after initial evaluation. Primary outcome is to evaluate the effect of treatment with home-base tDCS in patients with fibromyalgia. Secondary outcomes are: compare the effect of active home-based tDCS and sham in cortical neurophysiological processes and subcortical to stimulation with TMS and standardized noxious stimuli with and without concomitant conditioned Pain Modulation (CPM) in pain threshold outcomes to the test mechanical pressure, heat-algesic stimulus, cortical excitability parameters \[evoked rest motor (MEP) MEP enough to evoke amplitude of 1 mV peak to peak, silent period (SP), motor threshold (MT), variation in blood volume and oxygenation cortical motor area \[oxy-hemoglobin concentrations (Hbo) / deoxy-hemoglobin (HBr)\] optically functional neuroimaging (NIRS) and variation in the frequency of alpha and beta waves of motor area stimulated by tDCS assessed by electroencephalogram (EEG). In surrogate outcome, the investigators will compare the effect of active home-sham tDCS the tDCS in pain levels and functional capacity, catastrophic thinking, bookmark levels of neurotrophic activity (BDNF) and astrocytic (S100 beta).

Eligibility Criteria:
Inclusion Criteria:

* have chronic pain fibromyalgia according to the criteria of the American College of Rheumatology
* Pain unresponsive to analgesics such as paracetamol, acetyl salicylic acid, Ibuprofen, Carisoprodol, Zanaflex (Tizanidine) and Codeine
* Give informed consent to participate after initial evaluation.

Exclusion Criteria:

* Pregnancy
* Treatment with carbamazepine and gabapentin
* The. Metallic implant in the brain
* Medical devices implanted in the brain
* Alcohol or drug abuse history in the last 6 months
* Suffering from severe depression (with score\> 30 on the Beck Depression Inventory)
* History of neurological disorders
* Unexplained fainting History
* History of head trauma or momentary loss of consciousness (self reported)
* Neurosurgery History
* Decompensated systemic diseases, and chronic inflammatory diseases (lupus, rheumatoid arthritis, renal failure and hepatitis).