Neurofeedback/EEG entails the use of sensors, placed on the scalp in order to retrain the brainwaves.  Brainwaves vary from slow to fast.  Generally, the faster they go, the more alert and focused we become (to a point).  In this way patients can learn to reduce anxiety, depression, pain and distractibility, and to improve mental focus, learning, memory and specific bodily functioning.  Neurofeedback can also be used to enhance peak mental performance in areas of work, school or sports.