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Transcranial Direct Current Stimulation

Background and objective : Transcranial direct current stimulation (tDCS) was a neurophysiologic technique using weak electrical currents (1-2 mA) to modulate the activity of neurons in the brain. It was discovered in the 1800, and then reintroduced by the reasonably well-controlled experiments 12 years ago. They suggested that electrodes placed on the head can produce noticeable neurological changes depended on the current direction. This study aims to review a basic technique of the instrument, mechanism of action, and application in clinical researches of tDCS. Material and Method: The tDCS studies were thoroughly reviewed in MEDLINE database using the key words “Transcranial direct current stimulation, tDCS, noninvasive brain stimulation, neurophysiologic technique” from 1998 to 2010. Some information was derived from transcranial stimulation textbook. Results: The basic technique of the instrument, mechanism of action, application in clinical researches such as stroke, pain syndrome, and craving; safety, side effect, and precaution of tDCS are described. Conclusion: tDCS study is rapidly increasing and accepted as a noninvasive technique. It’s easy to use and safe. And for the date, the outcomes of tDCS in clinical researches are preferable with very little side effects.    Key words: Transcranial direct current stimulation, tDCS, noninvasive brain stimulation, neurophysiologic technique.