Biofeedback is a technique in which people use feedback from a devise such as an EEG (electroencephalograph) used to measure brain wave activity and EMG (electromyography) used to measure muscle tension. These and other similar machines give the practitioner and patient information needed to control involuntary functions such as blood pressure and heart rate. By monitoring and then controlling these functions, the patient is able to treat such ailments as chronic pain, headaches, and migraines.
How does Biofeedback work?

Exactly how this healing technique works is still not understood scientifically. Logically, putting the patient in a more relaxed state, thus lowering blood pressure, eases the stress on other involuntary functions and thus lowers or eliminates the pain and discomfort of headaches, migraines and chronic pains

To learn more about this healing method, numerous websites and biofeedback organizations will help you get started. You may want to try www.dmoz/health/alternative/biofeedback to get a more detailed understanding of the treatment, places to find practitioners, and biofeedback organizations throughout the world.