Whether the transcranial direct current stimulation (tDCS) can help to relieve pain?

Abstract

The neuromodulating techniques are promising additional methods in chronic pain treatment, specially for the patients with chronic pain resistant to other methods of treatment. Difficulties in effective pain therapy may be caused by the cortical reorganization in the central nervous system in chronic pain patients. Methods used to alter central nervous system functioning, can be the useful tool for the treatment patients with chronic pain. According to the recent years publications, transcranial direct current stimulation (tDCS) can be effective as a method of treatment in some chronic pain conditions. Physiological researches performed during tDCS stimulation indicates a multidirectional mode of action of it. In this technique the weak current, causing only a moderate change in the polarity and excitability of the cortex laying under the stimulating electrode is being used. Positive, anodal stimulation increased the level of excitation, cathodal stimulation causes inhibition of the excitation. Some evidences confirmed possibility of action tDCS by mi-opioid system, by voltage gated sodium channel, dopamine receptors (D2), serotonin receptors (5-HT). After tDCS stimulation of the NMDA receptor activation was observed. The efficacy of transcranial direct current stimulation was confirmed in studies in patients with central pain after stroke, pain after spinal cord injury, visceral pain, migraine headaches, complex regional pain syndrome (CRPS), fibromyalgia, phantom pain. In this pain conditions series of tDCS stimulation with 2 mA current over motor cortex resulted in significant decreased in pain. There is some information about efficacy of tDCS in acute pain treatment. In the published studies no serious adverse events were described after tDCS stimulation.