Electrodermal screening is different from electrical impedance scanning, in which an electrical current is sent through deep body tissues to detect changes due to cancer. The U.S. Food and Drug Administration has reviewed electrical impedance scanning and allowed it to go into clinical trials to determine whether it can help to diagnose breast cancer.
Other common name(s): EAV (electroacupuncture according to Voll), bioelectric functional diagnosis, Vegatesting
Scientific/medical name(s): none
Electrodermal screening is used to diagnose disease by measuring the electrical resistance on the skin's surface. The purpose is to detect energy imbalances along invisible lines of the body described by acupuncturists as meridians (see Acupuncture).
Available scientific evidence does not support electrodermal diagnosis as a method that can diagnose, cure, or otherwise help people with cancer.
How is it promoted for use?
Proponents claim the devices can help detect energy imbalances in the body, help with the selection of specific treatments, measure the progress of therapy, and even detect disease before it becomes apparent. They claim that some of the devices can be used to find allergies, organ weakness, parasites, heavy metal intoxication, dietary intolerances, pesticide burden, nutrient deficiencies, and more.
What does it involve?
This kind of testing may be done by a homeopath, acupuncturist, naturopath, chiropractor, or other practitioner (see Homeopathy, Acupuncture, Naturopathy, Chiropractic). The testing device sends a tiny electrical current, too small to be detected by the patient, through a probe. The patient may hold a probe in one hand, while a second probe is touched to another part of the body. This completes a low-voltage electrical circuit, and a computer screen or a needle on a gauge reads out a number between 0 and 100. This may be repeated at many different places on the skin. These numbers are used to decide if the patient's energy is out of balance.
If the patient is being tested for a type of treatment, samples of various remedies may be tried as the probe is touched to the problem area. Remedies may include homeopathic liquids and dietary or vitamin supplements. Different substances are tested until one is found that "balances" the energy disturbance.
What is the history behind it?
Electrodermal screening has its earliest roots in what was called galvanic skin testing. The galvanic skin response, a method of measuring the electrical resistance of the skin, was discovered in the early 1900s. Galvanic skin testing detects sweat on the skin, and more sweat produces better electrical conduction.
In the 1950s, a West German physician and acupuncturist named Reinhold Voll combined acupuncture theory with galvanic skin response technology. He tested the skin along various points with particular attention to the acupuncture meridians (see Acupuncture). This is how galvanic skin response testing became known as electrodermal screening.
The first device for electrodermal screening was called the Vegatest, followed by the Vegatest II. Later versions have been called Accupath 1000, Biotron, Computron, Dermatron, DiagnoMètre, Eclosion, Elast, Interro, LISTEN System, MORA, Natrix Physiofeedback System, Omega AcuBase, OmegaVision, Orion System, Prophyle, Punctos III, and Vitel 618, among others. Because the devices are simple to make, new brands and different-looking devices are created often.
Changes in galvanic skin response are still sometimes used in mental health research studies or to detect hot flashes in menopausal women. For most purposes, this method has been replaced with more advanced types of testing. Galvanic skin response changes are still used in lie detector tests, along with several other measures such as pulse, breathing, and blood pressure.
What is the evidence?
Available scientific evidence does not support electrodermal screening (galvanic skin response) as a reliable aid in diagnosis or treatment of cancer or other illness.
The Food and Drug Administration (FDA) requires that any device that is used to diagnose or treat diseases be proven effective before it can be marketed. None of these devices has earned FDA approval for diagnostic use, although several are registered as "galvanic skin response detection devices." The FDA has warned several manufacturers to stop making false claims about diagnosis, and has banned some devices from being imported. Various licensing boards in the United States have disciplined licensed practitioners who have used electrodermal screening for diagnosis or treatment selection. In spite of all this, the devices are still frequently advertised and promoted as diagnostic tools.
Are there any possible problems or complications?
Electrodermal screening itself is relatively safe, although people with implanted pacemakers should avoid electrical current. However, misdiagnosis and improper treatment may cause problems. For example, people have had healthy teeth removed based on recommendations from this type of screening. One man was told he did not have cancer, when in fact, he did. His treatment was delayed for several months because of misinformation.
Relying on this diagnostic method alone while avoiding or delaying conventional diagnosis and medical care for cancer may have serious health consequences.
More information from your American Cancer Society
The following information on complementary and alternative therapies may also be helpful to you. These materials may be found on our Web site (www.cancer.org) or ordered from our toll-free number (1-800-ACS-2345).
The ACS Operational Statement on Complementary and Alternative Methods of Cancer Management
Barrett S. Quack "Electrodiagnostic" Devices. Accessed at: www.quackwatch.org on May 30, 2008.
Carpenter JS, Monahan PO, Azzouz F. Accuracy of subjective hot flush reports compared with continuous sternal skin conductance monitoring. Obstet Gynecol. 2004;104:1322-1326.
Ernst E (ed). The Desktop Guide to Complementary and Alternative Medicine. New York, NY: Mosby 2001
Food and Drug Administration. FDA Guidance document for Galvanic Skin Response Measurement Devices. Accessed at: www.devicewatch.org/reg/gsr.shtml on June 20, 2008.
Picard R, Ahn H, Daily S, et al. Research on Sensing Human Affect. Accessed at: http://affect.media.mit.edu/areas.php?id=sensing on June 2, 2008.
Semizzi M, Senna G, Crivellaro M, Rapacioli G, Passalacqua G, Canonica WG, Bellavite P. A double-blind, placebo-controlled study on the diagnostic accuracy of an electrodermal test in allergic subjects. Clin Exp Allergy. 2002;32:928-932.
Stojadinovic A, Nissan A, Gallimidi Z, et al. Electrical impedance scanning for the early detection of breast cancer in young women: preliminary results of a multicenter prospective clinical trial. J Clin Oncol. 2005 23:2703-2715.
Note: This information may not cover all possible claims, uses, actions, precautions, side effects or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for consultation with your doctor, who is familiar with your medical situation.
Last Revised: 11/01/2008