Noninvasive Brain Stimulation: Challenges and Opportunities for a New Clinical Specialty

Noninvasive brain stimulation refers to a set of technologies and techniques with which to modulate the excitability of the brain via transcranial stimulation. Two major modalities of noninvasive brain stimulation are transcranial magnetic stimulation (TMS) and transcranial current stimulation. Six TMS devices now have approved uses by the U.S. Food and Drug Administration and are used in clinical practice: five for treating medication refractory depression and the sixth for presurgical mapping of motor and speech areas. Several large, multisite clinical trials are currently underway that aim to expand the number of clinical applications of noninvasive brain stimulation in a way that could affect multiple clinical specialties in the coming years, including psychiatry, neurology, pediatrics, neurosurgery, physical therapy, and physical medicine and rehabilitation. In this article, the authors review some of the anticipated challenges facing the incorporation of noninvasive brain stimulation into clinical practice. Specific topics include establishing efficacy, safety, economics, and education. In discussing these topics, the authors focus on the use of TMS in the treatment of medication refractory depression when possible, because this is the most widely accepted clinical indication for TMS to date. These challenges must be thoughtfully considered to realize the potential of noninvasive brain stimulation as an emerging specialty that aims to enhance the current ability to diagnose and treat disorders of the brain.