Neurofeedback works based on the principles of operant conditioning as a way to reinforce positive/balanced brain functioning while inhibiting less optimal or dysregulated brain activity. Simply put, the person gets rewarded when healthy, balanced brainwave patterns are occurring, which then get strengthened by repetition.
Sensors are placed on the scalp over specific regions of the brain associated with a given symptom profile, which then assess and monitor the person's actual electrical brainwave patterns. There is nothing that is invasive, as the sensors only serve to read brainwave activity. The sensors allow the person and clinician to "get a peek" at the brainwave activity that is processed by a computer, and which is converted into images that are presented virtually "live" as they are occurring.
What appears on the screen can be either simple or complex, and the client can choose from various feedback programs that would be pleasant and engaging. A child might choose a video game where a rocket ship flies through space; a teen might choose to play a jet-ski game, while an adult might like to see some pleasant scenery. Something relatively simple, such as the flame of a candle or snow falling on a Celtic countryside among many more feedback programs can be chosen. All of these templates, though, will serve to realign, reshape, and rebalance the brainwave activity to more optimal and functional patterns.
The "game" one plays in a Neurofeedback training session are not like the ones played on a PC, Play Station or X-Box. The client watches a screen but there are no hand-held controllers, keyboards, or joysticks. The space ship will fly faster and pick up bonus points, or the flame of the candle might rise, or a gentle summer rain shower may fall when more balanced brain activity is being produced. The training game is calibrated so that the brain is gradually challenged to correct imbalances and to regulate itself. By changing the targeted brainwave patterns, one learns how to gain control over and to regulate brain states, feeling more relaxed, flexible, and centered.
Everything happening in the game is offering the brain information about its own functioning so it can regulate itself. Your job is to just to sit back and allow the brain to respond to the feedback.
It is important to note that the changes in brainwave activity are not introduced or programmed into the brain by the clinician; their role is to monitor the brainwave activity, setting the threshold levels for when goals are met and when rewards are applied. The changes might be only brief at first, but with additional training, they become more easily accessed and sustained as the brain learns how to become more self-regulated. In essence, with the help of a computer, a child or adult learns how to strengthen and re-train their brain, producing new positive patterns while breaking up old negative or maladaptive patterns that have been created in response to various stressors.
Some people describe Neurofeedback training as a way to build "brain strength" and flexibility. Others see it as increasing mental/brain "fitness", similar to cardiovascular training for the body. Unlike physical exercise, though, a life-long commitment to training is not required. Once these new patterns have been trained, it's hard for your brain to forget them, meaning that once the brain has been trained the positive effects remain.