For centuries, followers of ancient eastern practices such as meditation and yoga have claimed they could control body functions. In the western world, this ability has been documented in the last several decades. An NIH panel found biofeedback was moderately effective in relieving many types of chronic pain, such as tension headaches and some types of insomnia. They also found biofeedback was better than relaxation therapy for treating migraine headaches.

The effects of biofeedback can vary significantly from person to person. Under the guidance of a biofeedback therapist, the patient concentrates on changing a specific physiological process, such as heart rate, temperature, perspiration, blood flow, brain activity, or muscle tension. A monitor hooked to the skin with electrodes measures changes in the function being altered. Tones or images produced by the monitor inform the patient when he or she achieves the desired results. The process is repeated as often as necessary until the patient can reliably use conscious thought to change physical functions.

Biofeedback is often a matter of trial and error. Patients must learn to adjust their thinking, and mentally connect alterations in their thought, breathing, posture, and muscle tension with changes in their physiologic functions, something that is generally controlled unconsciously.

There are at least five different ways to measure body functions for biofeedback purposes. An electromyogram (EMG) measures muscle tension. It is used to help heal muscle injuries and relieve chronic pain and incontinence. Thermal biofeedback provides information about skin temperature, which is a good indicator of blood flow. Several health problems are related to blood flow, such as migraine headaches, Raynaud?s disease (problems of blood circulation in the fingers and toes which makes them feel very cold), anxiety, and high blood pressure. Electrodermal activity (EDA) shows changes in perspiration rates, which is used in treating anxiety. Finger pulse measurements are used to reflect high blood pressure, heart beat irregularities, and anxiety. Breathing rate, which is used to treat asthma and hyperventilation and to promote relaxation, is also monitored.

Although biofeedback has no direct effect on the development or progression of cancer, it can improve quality of life for some people with the disease. Research has found biofeedback can help patients regain urinary and bowel continence after surgery. However, in one randomized, controlled clinical trial, relaxation therapy was more useful than biofeedback in reducing some of the side effects of chemotherapy. The NIH has approved the use of biofeedback, in addition to conventional medicine, in the treatment of chronic pain and insomnia.

Biofeedback is considered a safe technique. It is noninvasive and requires little effort. It does, however, require a trained and certified professional to control the monitoring equipment and interpret the changes. Battery-operated devices sold for use in the home have not been found to be reliable.