Biofeedback

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Biofeedback is a non-medical process that involves measuring a subject's specific and quantifiable bodily functions such as blood pressure, heart rate, skin temperature, sweat gland activity, and muscle tension, conveying the information to the patient in real-time. This raises the patient's awareness and therefore the possibility of conscious control of those functions.

By providing the user access to physiological information about which he or she may be unaware, biofeedback may allow users to gain control of physical processes previously considered an automatic response of the autonomous nervous system. Interest in biofeedback has waxed and waned since its inception in the 1960s; it is, however, undergoing something of a renaissance during the early 21st century, which some experts attribute to the general rise in interest about all alternative medicine modalities. Small biofeedback machines are becoming available for use in the home.

The "Association for Applied Psychophysiology and Biofeedback", or "AAPB" is a non-profit scientific and professional society for biofeedback practitioners. Originally called "The Biofeedback Research Society", its name was first changed to the "Biofeedback Society of America," and then it was once again changed to its latest name.

Contents 1 Origins 2 Major modalities 2.1 Electromyograph 2.2 Feedback thermometer 2.3 Electrodermograph 2.4 Electroencephalograph 2.5 Photoplethysmograph 2.6 Pneumograph 2.7 Capnometer 2.8 Hemoencephalography 3 Biofeedback in electronic games 4 Biofeedback in art, music, etc. 5 Criticisms 6 External links 6.1 University project 6.2 Open source project 7 Notes and references

[edit] Origins

Donald Shearn first demonstrated biofeedback using operant conditioning of heart rate. (1962). Neal Miller later used this procedure, and hypothesized that any measurable physiological behavior within the human body would respond in some way to voluntary control.

DiCara & Miller (1968) found that by stimulating the pleasure center of a paralyzed rat's brain with electricity thereby rewarding them with something that might make them act in some way to make the physiological changes, it was possible to train them to control phenomena ranging from their heart rate to their blood pressure and body temperature ^[1]. Until Miller's research, it was believed by the scientific community that physiological processes (e.g. heart rate) were solely under the control of the autonomic nervous system and not responsive to conscious effort^[2]. Miller later retracted many of his claims because he was unable to replicate much of the data that he had published with Leo DiCara,the primary graduate assistant with whom he published all of his biofeedback results. One year after receiving a tenured position at the University of Michigan because of his groundbreaking work with Miller, Leo DiCara committed suicide.

The hypotheses proposed by Miller and colleagues make up one of three major approaches to understanding the mechanism of self-regulation of the body. Voluntary control of the autonomic nervous system had previously been considered impossible, something only controlled by conditioning.

Other threads of inquiry that led to the present-day "biofeedback" emerged from clinical attempts to use mind/body self-regulation techniques in healthcare. Dr. Elmer Green of the Menninger Foundation performed some of the original research on the limits of human self-regulation of processes normally controlled by the unconscious mind applied to the treatment of migraine headaches and hypertension. Dr. Barbara Brown was the first to coin the word "biofeedback" during the early days of experimentation, at the same time as the formation of the Biofeedback Research Society. Other early pioneers were interested in the study of "consciousness" and looked towards electroencephalogram (EEG) self-regulation as a way to approach mind vs. brain dichotomy (see the work of Dr.Kamiya). Other early efforts in the field of biofeedback were directed toward the examination of claims by yogis and others who meditate who were able to demonstrate mind/body control and markers of states of consciousness.^[3] See Elmer Green et al. Beyond Biofeedback and Barbara Brown Stress & The Art of Biofeedback for some early writings.

[edit] Major modalities

[edit] Electromyograph

An electromyograph, or EMG is one of the most commonly used modalities in biofeedback treatment. An EMG in a biofeedback setting typically uses electrodes in order to measure muscle action potentials. These action potentials result in muscle tension. The patient can learn to recognize the way tension subjectively feels by using the objective EMG readings, and as a result learn to control the muscle tension. EMG is used as a relaxation technique to ease tension in the muscles causing backaches, neck pain, TMD, incontinence, and tension, migraine, and cluster headaches. EMG is also used in the process of muscle rehabilitation, such as in cases of paralysis resulting from Cerebral Palsy, stroke, and incomplete spinal cord lesions.

[edit] Feedback thermometer

A thermistor attached to the subject's digits or web dorsum measures the subject's skin temperature. Because there is a correlation between a drop in body temperature and the patient's experience of stress, a low temperature reading indicates the need to begin relaxation techniques. Temperature biofeedback can also help in treating certain circulatory disorders, such as Raynaud's disease, and can reduce the frequency and severity of migraines. The physiological processes which are being trained in this modality are vasoconstriction and vasodilation, where blood vessel size is a result of the contraction and relaxation of smooth musculature in the vessel walls. The mechanism being trained in warming exercises is a beta-adrenergic vasodilator mechanism. ^[4]

[edit] Electrodermograph

In electrodermograph training, sensors measure the activity of a patient's sweat glands. The amount of electrical resistance measured on the skin indicates the level of anxiety. This information can then be used to treat emotional disorders such as phobias, anxiety and stuttering. The best-known use of this method of biofeedback is in polygraph machines. Galvanic skin response meters are currently gaining popularity in hypnotherapy and psychotherapy practices, so subtle physiological changes that indicate emotional arousal can be more easily detected.

[edit] Electroencephalograph

An electroencephalograph, or EEG monitors the activity of brain waves. These brain waves correspond to different mental states, such as wakefulness (Beta waves), relaxation (Alpha waves), calmness (Theta waves), and light sleep and deep sleep (Delta waves).

[edit] Photoplethysmograph

Photoplethysmographs, or PPGs, in biofeedback are used to measure peripheral blood flow, heart rate, and heart rate variability(HRV). To measure HRV, PPGs measure the varying distances between heart beats, also known as the interbeat interval (IBI). This data guides users in finding a breathing pattern that increases their variability.

[edit] Pneumograph

A pneumograph measures abdominal/chest movement (as when breathing), usually with a strain gauge. They are used to detect breathing rate, and correct ineffective breathing patterns such as thoracic breathing, reverse breathing, and apnea. They are also often used in conjunction with a PPG in HRV training.

[edit] Capnometer

A capnometer measures end-tidal CO2 with an infrared detector. All biofeedback training that employs the use of a capnometer aims at normalizing end-tidal CO2 at 5%.

[edit] Hemoencephalography

Hemoencephalography, or HEG biofeedback is an attempt at functional infrared imaging. As its name describes, it measures the differences in the color of light reflected back through the scalp based on the relative amount of oxygenated and unoxygenated blood in the brain. The reliability and applicability of HEG is still in question and it is almost exclusively used for biofeedback.

[edit] Biofeedback in electronic games

Charles Wehrenberg implemented competitive-relaxation as a gaming paradigm with the Will Ball Games circa 1973. In the first bio-mechanical versions, comparative GSR inputs monitored each player's relaxation response and moved the Will Ball across a playing field appropriately using stepper motors. In 1984 Wehrenberg programmed the Will Ball games for Apple II computers. The Will Ball game itself is described as pure competitive-relaxation; Brain Ball is a duel between one player's left and right brain hemispheres; Mood Ball is an obstacle based game; Psycho Dice is a psycho-kinetic crap game.^[5] In 2001, the company Journey to Wild Divine began producing biofeedback hardware and software for the Macintosh and Windows operating systems. Third-party and open-source software and games are also available for the Wild Divine hardware.

[edit] Biofeedback in art, music, etc.

Biofeedback data and biofeedback technology are used by Massimiliano Peretti in a contemporary art environment, the Amigdalae project. This project explores the way in which emotional reactions filter and distort human perception and observation. During the performance, biofeedback medical technology, such as the EEG, body temperature variations, heart rate, and galvanic responses, are used to analyze an audience's emotions while they watch the video art. Using these signals, the music changes so that the consequent sound environment simultaneously mirrors and distorts the viewer's emotional state. ^[6][7] More information is available at the website of the CNRS French National Center of Neural Research[1].

David Rosenboom has worked to develop musical instruments that would respond to mental and physiological commands. Playing these instruments can be learned through a process of biofeedback.

As well as bands and music, in the mid-seventies, there was an episode of the television series, "The Bionic Woman", that featured a doctor who could "heal" himself using biofeedback techniques to communicate to his body and react to stimuli. For example, he could exhibit "super" powers, such as walking on hot coals, by feeling the heat on the sole of his feet and then convincing his body to react by sending large quantities of perspiration to compensate. He could also convince his body to deliver extremely high levels of adrenalin to provide more energy to allow him to run faster, jump higher, etc. When injured, he could slow his heart rate to reduce blood pressure, send extra platelets to aid in clotting a wound and increase white blood cells to an area to attack infection.[2]

[edit] Criticisms

Undisputed scientific research in the possible application of biofeedback is lacking. While many claims have been made as to treatments for various conditions, it is suggested that the applications of real biofeedback are limited, specific and generally well known.^[8] Specifically, claims that biofeedback is an effective treatment for ADHD (and many other conditions) are viewed with skepticism by some within the medical community.^[9][10] Furthermore, some believe that the use of biofeedback (like most alternative medical "treatments") for stress and anxiety is expensive, though less so than pharmaceuticals, and might be replaced with simple relaxation training, meditation, and self-hypnosis.

[edit] External links

• Biofeedback FAQ from the Mayo Clinic
• The Association for Applied Psychophysiology and Biofeedback (AAPB)
• The Israeli Association for Applied Psychophysiology and Biofeedback
• The International Society for Neurofeedback Research (ISNR)
• Biofeedback from Zing Health in Australia

[edit] University project

• University of Vienna : cours Biomedical Engineering, Electromyography (EMG)
• Hardware, EMG (Escuela de Ingeniera de Antioquia, Colombie)
• Electroencephalographe,EEG, Wireless (Cornell University, Ithaca, NY, USA)

[edit] Open source project

• Stress et biofeedback, bioamplificateur, EMG (French)
• OpenEEG project

[edit] Notes and references