Biofeedback

Biofeedback is the process of measuring and quantifying an aspect of a subject's physiology, analyzing the data, and then feeding back the information to the subject in a form that allows the subject to enact physiological change.

The word "biofeedback" was coined in the late 1969 to describe laboratory procedures (developed in the 1940's) that trained research subjects to alter brain activity, blood pressure, muscle tension, heart rate, galvanic skin response and other bodily functions that are not normally controlled voluntarily. Biofeedback is a training technique in which people are taught to improve their health and performance by using signals from their own bodies.

Biofeedback describes a process in which a subject is given immediate information about his or her bodily processes, which are usually unconscious. The subject is able to control those processes through training and practice. It is an experimental treatment for disturbances of bodily regulation, such as hypertension. The best-known applications of biofeedback include high blood pressure, migraines, and epilepsy, though recently promise has been shown—particularly when using EEG neurofeedback—regarding ADD/ADHD, stroke/ischemia, traumatic brain injury, phobias, mood disorders, tourette's syndrome, obsessive-compulsive disorder, autism, and schizophrenia.

For a mechanical analogy, consider the classic feedback device: the steam valve. As the steam causes a rotor to turn, the centrifugal force of the rotation causes levers to rise, or strings to fly out, in the same way that if you rapidly turn yourself, your arms fly outward.

The levers on a steam device control the flow of steam, the faster the rotation the smaller the steam vent, the smaller the vent the slower the rotation. The size of the vent, the speed of rotation and the force of the arms closing the valve can all be adjusted so that the rotating axle maintains a consistent speed, so long as the supply of steam is constant.

The same principles hold for feedback within the human body: as a subject eats food, its mouth and stomach fills, and internal sensors send a signal ("satisfied") causing the subject to stop eating.

The ordinary biological feedback of daily living can be enhanced by using mechanical transducers (devices which measure energies). One can press a piece of plastic against one's palm which turns color depending on temperature. Quickly one learns to make the color redder and redder (the color is arbitrary, it could be bluer and bluer). If a subject is prone to headaches, it can prevent, inhibit or relieve a headache by warming its hand. One may measure the way one's skin conducts electricity and learn to make the skin less conductive.

There is significant evidence that hyperactive boys tend to make high amplitude slow brain waves which are associated with inefficient faster brain waves. The child can be taught to reduce the amplitude of signals slower than 7 pulses per second (Hertz) and to increase the strength of the signals running 13-14 Hertz. Such children tend to become more social, more effective at school work, and they perform more adroitly on IQ and other tests.

Various forms of biofeedback are said to relieve differing symptoms: EEG biofeedback is used to relieve pain and insomnia; GSR (skin conductance) tends to be used for anxiety suppression; muscle tension (EMG) for headache relief and restoration of movement and strength.

Technology allows monitoring of internal sources for nearly silent and invisible information and converts it to visual and/or auditory feedback to provide the user or subject a new basis upon which to act. As a result, autonomic functions can be moderated, as well as new therapies learned.

The learning achieved by biofeedback is robust, stable, reliable and readily acquired.

Blood pressure feedback is less readily accomplished than temperature feedback. However, as temperature and blood pressure are strongly correlated it is possible to learn to manage one physiological dynamic directly while indirectly influencing another.

A trend which is readily discernible is that biofeedback practitioners who initiated their practice using temperature change (which is easily done and is markedly reliable), tend to add muscle tension (EMG) (which is perhaps even more easily done than temperature). Temperature and muscle tension biofeedback are the most widely practiced forms.

Significantly, two methods which are more difficult to achieve and to stabilize, have begun consistently to be used to supplement muscle tension and temperature based training. These methods are Heart Rate (HRV) and EEG. Heart rate is less commonly observed by the ordinary person, although most individuals have noticed the heart rate acceleration and increase in pressure that accompanies startle, fear and marked physical effort. Animals include the human animal seem to be entirely unconscious of the complex electrical activity of the brain. However, it is relatively simple to train animals and humans to produce specific signals in the brain, or to intensify or to reduce the strenghth of certain frequencies.

See related links below.

External Links

• EEG Biofeedback FAQ (http://www.eegbiofeedback.cz/english/english.php?menu=faq)
• Biofeedback and Neurofeedback Yahoogroup (http://health.groups.yahoo.com/group/biofeedback/)
• Biofeedback articles, workshops, equipment, and supplies (http://www.bio-medical.com)de:Biofeedback