Humans have many methods of changing their states of consciousness, which in turn impacts their brain waves. For instance, meditation has been used since ancient times to change thought patterns in various cultures around the world. Neurofeedback is a technique which uses modern technology and scientific knowledge to control and train brain waves. It is non-invasive, and must be done as part of a regular training program, usually between 30 and 40 sessions, each lasting 30-40 minutes.
Neurofeedback, also known as EEG biofeedback belongs to a group of therapies called biofeedback. Biofeedback works on the principle that if a person can see his or her bodily functions in real time, s/he can learn to control them. Biofeedback can be applied to different bodily processes which are usually involuntary, such as muscle tension, body temperature and blood pressure. It is used to treat a variety of conditions including anxiety, migraines, chronic pain, and incontinence.
The goal of neurofeedback is to train the brain to regulate itself, and to help the person training to understand when their brain is in the desired state. Eventually, the patient can control these processes without being monitored. The feedback is given based on sensors which are placed on the head using Electroencephalography (EEG) readings of brain wave activity in the form of games or videos.
For instance, someone with Attention Deficit Disorder (ADD) may not be aware of when their brain is in a focused state, or recognize when their mind is wandering. During the neurofeedback training, they can see exactly when their mind is wandering in real time, and learn how to return their focus to the activity at hand. (Read more about who can benefit from neurofeedback).
Using neurofeedback, the brain learns to regulate its activity by playing games or watching videos as part of a training program. Over time, the ability to control the brain waves can be applied in real world situations, for instance, by helping them relax in stressful situations, or concentrate during class.
Neurofeedback is a form of therapy, not a medication, and therefore is non-invasive and has little to no negative side effects. The electrodes simply monitor brain waves using EEG, and the client receives feedback instantly based on the EEG readings. Like every form of exercise, neurofeedback requires regular training. Most studies have found that patients start seeing improvements after 5-10 sessions, and a full course of training is usually between 30 and 40 sessions. Studies have shown that after completing a complete neurofeedback program, patients experienced improvements which lasted years.
https://www.webmd.com/a-to-z-guides/biofeedback-therapy-uses-benefits#1
https://www.medicalnewstoday.com/articles/265802.php