Biofeedback is a method for learned control of physiological responses of the body.

These responses can be either in the voluntary system, such as skeletal musculature, or in the involuntary, or autonomic nervous system such as heart rate, vascular responses (frequently indirectly measured as temperature), and sympathetic discharges (measured by the electrical skin response).

The experimental data to support the feasibility of such learned controls first appeared in the 1950s with the work of psychologists such as Neal E. Miller.

They increased in the 1960s, mostly through animal studies, although some experiments with humans were also performed. Next came a joint endeavor between experimental psychology and physiology. It became clear that certain dramatic gains could be achieved by using psychological techniques on patients with medical problems.

Autonomic and disease specificity and the patient's psychological state must be considered before treatment can begin. For example, learning to relax certain muscles may be somewhat useful in many disorders but may not be the most effective treatment.

An anxious patient with tachycardia (rapid heartbeat) benefits much more by learning to slow his or her heart rate rather then by relaxing muscles.

Biofeedback can be used to control certain biological responses that cause health problems, such as headaches, chronically taut muscles from accidents or sports injuries, asthma, high blood pressure, and heart arrhythmias.

It is often used instead of, or as a complement to, drugs in pain control.

The training methods are relatively simple, although they require complex and precise instrumentation.

After the desired mode of treatment has been determined for a given disorder, the patient is connected to a computer or an equivalent instrument by a polygraph, and the response is presented back to the patient in either a binary or an analog fashion.

In the binary approach, a threshold is set, and whenever the patient crosses that threshold, a light or music indicates that the patient is succeeding.

In the analog approach the patient monitors the actual numbers in electrical units that represent bodily states such as heart rate, temperature, or vasculature.

The two techniques can be combined. Initially the criteria are made easy by the therapist, and as the patient succeeds, the task is made more difficult.

Ultimately the patient should become his or her own therapist and eventually control specific body functions without the use of instrumentation.

What Bio-feedback is used for
1. Migraine headaches, tension headaches, and many other types of pain 2. Disorders of the digestive system 3. High blood pressure and its opposite, low blood pressure 4. Cardiac arrhythmias (abnormalities, sometimes dangerous, in the rhythm of the heartbeat) 5. Raynaud's disease (a circulatory disorder that causes uncomfortably cold hands) 6. Epilepsy 7. Paralysis and other movement disorders