Emerging subspecialties in Neurology: transcranial stimulation

Treating neurologic disorders with noninvasive brain stimulation techniques has always been one of the major goals of neurophysiology and to a broad extent, of modern neurology and psychiatry. The first attempts date back at least to 50 AD, when the Roman physician Scribonius Largus used electric currents from torpedo fishes to treat headaches.1 Unfortunately, these initial efforts sank into oblivion until the 18th century. In the last 2 decades, thanks to technological improvements, noninvasive transcranial stimulation is re-emerging as an appealing and promising approach to be used in different fields of neurology and neuroscience, with the number of related publications increasing exponentially in both clinical and basic science studies. This new age is particularly due to the broad-spectrum use of 2 techniques called transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS). Despite the undoubted importance of conventional brain stimulation methods such as deep brain stimulation (DBS) or electroconvulsive therapy, TMS and tDCS present many favorable advantages both in terms of noninvasiveness and safety, with minimal or no side effects.