Neurofeedback (NFB), also called neurotherapy or neurobiofeedback, is a type of biofeedback that uses real-time displays of brain activity—most commonly electroencephalography (EEG)—in an attempt to teach self-regulation of brain function. Typically, sensors are placed on the scalp to measure electrical activity, with measurements displayed using video displays or sound. There is significant evidence supporting neurotherapy for generalized treatment of mental disorders and has been practiced over four decades, although never gaining prominence in the medical mainstream. NFB is relatively non-invasive and is administered as a long term treatment option, typically taking a month to complete. It is estimated over 15,000 clinicians, world-wide are using this technology.