A parent explains how it works:neurofeedback

“When the computer recognizes the brain waves performing correctly it releases a picture of the puzzle and an auditory ding as positive feedback or reinforcement to the brain. This encourages the brain to perform this way again.”

In more Detail:

Sensors are placed safely and comfortably on the head. These sensors listen to the brain’s electrical activity. The result of this monitoring is called an electroencephalograph, or EEG. The EEG brain waves are very tiny, so this information is digitized and amplified so it can be seen on a computer screen. The neurofeedback professional sets the computer so it will reward a mix of brain waves that will increase the brain’s healthy brain waves. This reward is called reinforcement. In this case, the behavior that is being increased is a healthy EEG or healthy brain behavior. When you have the right kind of brain waves, images on the computer screen appear that are pleasant and rewarding. This reward teaches the brain to produce healthier brain waves.

When more than one location on the brain is being trained at a time, all the locations must make healthy brain waves simultaneously for there to be a reward. Training multiple locations simultaneously increases the brain’s ability to coordinate its activity between locations. We have found that this healthy coordination, called comodulation, is the best measure of improvement when you do neurofeedback. We check for comodulation changes when we do our follow up brain map.

What does it look like when someone is doing neurofeedback?
Video: What is Neurofeedback?

You are sitting in a recliner facing a computer screen and up to seven sensors, which look like buttons, are attached to your head and ears. You relax and watch the computer screen. Whenever your brain is making better brain waves in all of up to four locations, puzzle pieces come up on the screen accompanied by a sound. You enjoy the change on the computer screen. While you are looking at the puzzle pieces that have resulted from your brain’s good work, there is a pause that allows your brain to consolidate the learning. Then the cycle starts again and another puzzle piece comes up on the screen as your brain makes healthy brain waves. Over time, your brain gets better and better at making more healthy and controlled brain waves. You might not be consciously aware of the changes. The neurofeedback professional follows the improvements, helping your brain make more controlled brain waves. Amazingly your brain learns to control your brain waves and your brain works better naturally. You do not have to do anything to make it work better. Your brain has learned while you were watching the computer screen. Like learning to ride a bike, your brain does not forget.. In fact, your brain keeps improving for quite a while even after you have completed your neurofeedback training sessions.

This is the easiest learning you will ever do.

NPR explains how it works:
Advanced Neurotherapy

Train The Brain: Using Neurofeedback To Treat ADHD from NPR Considering Neurofeedback For ADHD?
A growing number of parents see neurofeedback as an appealing alternative to medication to treat their child’s ADHD. The treatment is relatively simple and painless. First, a practitioner attaches three to 10 electrodes to the child’s head. Each electrode sprouts a lead, or wire, connecting it to a computer. The child sits in front of a screen displaying images that respond to the child’s brain activity. When the child has the right kind of brain activity — the images are rewarding or positive, for example — puzzle pieces might fall into place. Proponents say this helps encourage better behavior over time.
Follow this link and listen to “The Story” from the NPR website today November 1st, 2010.