Transcranial Direct Current Stimulation in the Treatment of Facial Pain.

Non-invasive neuromodulation techniques such as transcranial direct current stimulation (tDCS) enable researchers and health care professionals to gain unique insight into brain functions and to treat a number of neurological and psychiatric conditions. Repeated applications of anodal tDCS over the primary motor cortex (M1) have been shown to produce long-lasting relief of neuropathic pain. tDCS is a technique that can induce and modulate brain plasticity and thus be suitable for treating diverse chronic pain conditions, disorders associated with substantial reorganization of central nervous system activity. The number of published basic research and clinical papers in this field is increasing exponentially, but the number of studies that include patients with facial pain is still limited, and there are no "gold standards" with regard to how to treat the various kinds of pain disorders. Pharmacoresistant facial pain is a substantial burden for the patient as manifested by its interference with daily functioning and reduced health status associated with pain severity. Without doubt, further trials are needed to optimize stimulation parameters and find effective protocols for this disorder. In addition, evaluation of the clinical effects of tDCS shows that low-intensity electrical stimulation techniques are exceptionally suitable for gaining further insight into the functional role of a given brain region, e.g. how brain processes emerge and can be altered in anatomically distributed, but functionally connected, brain networks.