In the early 1940s US and UK scientists developed electronic devices to detect minute physical responses. At first, publicity focused on obtaining electrical signals from the brain, but the work of American scientists in the 1960s confirmed biofeedback's therapeutic value. Drs. Elmer and Alyce Green of the Menninger Foundation in Kansas used the method to study states of mind during yoga meditation; by the 1980s stress management courses using biofeedback were introduced to American primary schools. In the 1990s, better computer technology prompted further research.

KEY PRINCIPLES

 

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An extensive body of clinical research exists to support the claims of biofeedback. A 1996 study in the US showed that using biofeedback to relax shoulder muscles could ease tension headaches. A 1992 American study showed that muscular pain in the lower back responded to biofeedback, and a US government report in 1992 found patients could control incontinence with the technique. It is also being used at Yale University to control heart rate and blood pressure, and some American doctors use it to treat epilepsy.

Few doctors would have once believed that people could learn to influence blood pressure, let alone brain waves. Today, the evidence is conclusive and biofeedback's entry into the medical mainstream seems inevitable, although doctors question its reliability as a form of treatment.

The practitioner will show you how to use the biofeedback device, of which there are several types: a skin temperature (ST) gauge registers heat changes in the skin, a galvanic skin response (GSR) sensor measures the skin's electrical conductivity by the amount of sweat produced under stress, electromyographs (EMGs) use auditory or visual signals to indicate muscle tension, electroencephalographs (EEGs) show brain-wave activity, and electro­ cardiographs (ECGs) monitor heart rate.

 

Once the sensors are in place, you are taught to recognize signals that suggest relaxation. Techniques such as breathing and muscle relaxation help achieve the desired response (reduced blood pressure, for example). A state of relaxation is indicated by warm skin, low sweat gland activity, high levels of alpha waves from the brain, and a slow, even heart rate. Biofeedback takes practice; at least six half-hour sessions may be needed.