Biofeedback

Biofeedback is a form of complementary and alternative medicine (CAM) which involves measuring bodily processes such as blood pressure, heart rate, skin temperature, galvanic skin response (sweating), and muscle tension in order to raise a subject's awareness and conscious control of these functions. Devices as simple as mirrors and bathroom scales can be considered rudimentary biofeedback devices, insofar as the information they provide can help a person with issues related to posture and weight; more complex biofeedback devices have been used therapeutically with several conditions, including epilepsy, asthma, incontinence, irritable bowel syndrome, Raynaud's disease, chemotherapy-related nausea and vomiting, headaches, high blood pressure, and cardiac arrhythmias. Electraencephalogram-based biofeedback, which measures brainwaves and is usually called neurofeedback, has gained popularity in recent years as a treatment for attention deficit hyperactivity disorder, and is being studied as a potential treatment for anxiety, depression, and drug addiction.

By providing access to physiological information about which the user is generally unaware, biofeedback allows users to gain control over physical processes previously considered automatic.

Interest in biofeedback has waxed and waned since its inception in the 1960s; currently it is undergoing a bit of renaissance, which some ascribe to the general upswing of interest in complementary and alternative medicine modalities. Neurofeedback has become a popular treatment for ADHD, electromyogram (muscle tension) biofeedback has been widely studied and accepted as a treatment for incontinence disorders, and small home biofeedback machines are becoming available for a variety of uses.

Origins of biofeedback
Neal Miller, a psychology Ph.D and neuroscientist who worked and studied at Yale University, is generally considered to be the father of modern-day biofeedback. He came across the basic principles of biofeedback when doing animal experimentation conditioning the behavior of rats. His team found that, by stimulating the pleasure centers of the rats' brains with electricity, it was possible to train rats to control phenomena ranging from their heart rates to their brainwaves. Until that point, it was believed that bodily processes like heart rate were under the control of the autonomic nervous system and not responsive by conscious effort.

Dr. James S. Gordon, of the Washington DC-based Center for Mind-Body Medicine, testified before a House committee that "In 1961 when Neal Miller first suggested that the autonomic nervous system could be as susceptible to training as the voluntary nervous system, that people might learn to control their heart rate and bowel contractions just as they learned to walk or play tennis, his audiences were aghast. He was a respected researcher, director of a laboratory at Yale, but this was a kind of scientific heresy. Everyone 'knew' that the autonomic nervous system was precisely that: automatic, beyond our control."

Types of biofeedback
One variety of biofeedback is EEG feedback, which uses electrodes placed on the scalp to garner information about the user's brainwaves. This type of biofeedback is discussed in the article neurofeedback.

Other types of biofeedback include the following:
 * electromyogram biofeedback, which uses sensors and electrodes to measure muscle tension, and which is used to treat stress-related illnesses, such as asthma and ulcers
 * galvanic skin tension biofeedback, which measures the minute activities of sweat glands and which is used to treat anxiety-related illnesses, such as phobias and stuttering
 * temperature biofeedback, which measures skin temperature and has been used to treat migraine headaches and circulatory disorders.

Criticisms
While there is ample information about the use of neurofeedback for ADHD or electromyogram biofeedback for incontinence disorders, limited research has been done on some of biofeedback's other uses. Additionally, some believe that the use of biofeedback for stress and anxiety is an expensive treatment for difficulties which could be addressed with relaxation training, meditation, and self-hypnosis.

Possible beneficial side effects
Possible beneficial side effects attested by biofeedback supporters include improved ability to relax and concentrate, and either controlling or reducing levels of stress and pain.