Background: 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 1960s, 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.
Objective: 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.
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 is easy to use and safe. The outcomes of tDCS in clinical researches are preferable with very little side effects.