Thousands of practitioners use “electrodiagnostic” devices to help select their recommended treatment. Many claim to determine the cause of any disease by detecting the “energy imbalance” causing the problem. Some also claim that the devices can detect whether someone is allergic or sensitive to foods, deficient in vitamins, or has defective teeth. Some claim they can tell whether a disease, such as cancer or AIDS, is not present. One Mexican clinic even claimed that such a device could be used to cure cancer . The diagnostic procedure is most commonly referred to as Electroacupuncture according to Voll (EAV) or electrodermal screening (EDS), but some practitioners call it bioelectric functions diagnosis (BFD), bio resonance therapy (BRT), bio-energy regulatory technique (BER), biocybernetic medicine (BM), computerized electrodermal screening (CEDS), computerized electrodermal stress analysis (CDCSA), electrodermal testng (EDT), limbic stress assessment (LSA), meridian energy analysis (MEA), or point testing. EAV devices are marketed by several companies, most of which also sponsor seminars.
The first EAV devices were developed by Reinhold Voll, a West German physician who had been engaged in acupuncture practice in the 1950s . In 1958, he combined Chinese acupuncture theory with galvanic skin differentials to produce his EAV system. His first transistorized model was the Dermatron. A few years later, one of his students (another German physician named Helmut Schimmel) simplified the diagnostic system from approximately 850 points to 60 points, made small modifications to the equipment, and went on to help create the first model of the Vegatest. Subsequent variants include the AcuGraph, Accupath 1000, Asyra, Avatar, BICOM, Bio-Tron, Biomeridian, BioScan, BioTracker, Computron, CSA 2001, DBE204, Diacom, DiagnoMètre, Eclosion, e-Lybra 8, ELAST, Interactive Query System (IQS), Interro, I-Tronic, Kindling, LISTEN System, Matrix Physique System, Meridian Energy Analysis Device (MEAD), MORA, MSAS, Oberon, Omega Acubase, Omega Vision, Orion System, Phazx, Prognos, Prophyle, Punctos III, Quest4, Sensitiv Imago, SpectraVision, Syncrometer, Vantage, Vitel 618, and ZYTO.
Proponents claim that these devices measure disturbances in the body’s flow of “electro-magnetic energy” along “acupuncture meridians.”  Some are claimed to measure “vibrations,” “resonance,” or “stresses” associated with body tissues and/or organs. Actually, most devices are little more than fancy galvanometers that measure electrical resistance of the patient’s skin when touched by a probe. The device emits a tiny direct electric current that flows through a wire from the device to a brass cylinder covered by moist gauze, which the patient holds in one hand. A second wire is connected from the device to a probe, which the operator touches to “acupuncture points” on the patient’s other hand or a foot. This completes a low-voltage circuit and the device registers the flow of current. The information is then relayed to a gauge or computer screen that provides a numerical readout on a scale of 0 to 100. According to Voll’s theory: readings from 45 to 55 are normal (“balanced”); readings above 55 indicate inflammation of the organ “associated” with the “meridian” being tested; and readings below 45 suggest “organ stagnation and degeneration.” However, if the moisture of the skin remains constant—as it usually does—the only thing that influences the size of the number is how hard the probe is pressed against the patient’s skin. Some devices have all of their wires connected to the patient or generate their responses randomly so that the practitioner does not influence the results. The chart below is one version of Voll’s scale.
In the earlier devices, the number was indicated by a needle that moved over a dial gauge. Later versions, such as the Interro pictured below, make sounds and provide the readout on a computer screen. The treatment selected depends on the scope of the practitioner’s practice and may include acupuncture, dietary change, and/or vitamin supplements as well as homeopathic remedies.
Interro device. One probe is held in the patient’s hand. As the other probe is touched to the patient’s other hand or foot, a bar rises on the right side of the computer screen, accompanied by a noise.
The reading supposedly determines the status of various organs of the body. In 1986, while investigating the homeopathic marketplace for Consumer Reports magazine, I underwent testing with this device The Nevada Clinic in Las Vegas, Nevada. When the doctor left the examining room, I played with the device and I found that the movement of the bar and the loudness of the noise were determined only by how hard the probe was pressed to my skin . After the alleged problems are “diagnosed,” glass ampules containing homeopathic solutions may be placed in the metal honeycomb in the foreground and the tests are repeated to determine whether they are suitable for correcting the alleged “imbalances.”
Some EAV sellers make direct medical claims, some couch their claims in terms of correcting “imbalances,” and some pretend that the device is used for “stress testing.” In addition:
- Some devices are claimed to help the practitioner make as well as select the recommended remedies. The e-Lybra 8, for example, is said to provide “over 285,000 remedies at your fingertips” and to “make single or multiple remedies easily and quickly in any potency.” 
- Some devices are claimed to restore health by rendering signals that correct “imbalances.” A 1997 patent application for the LISTEN device, for example, states: “By determining the electrical resistance at different points on a patient, it is possible to determine which organs are affected by a disease. In addition, a patient can be treated by providing a radiofrequency electrical signal which restores electrical conductance at specific points to normal levels.” 
- Some practitioners claim to use their device as aid to diagnosis rather than the sole basis for diagnosis. However, I believe they say this to make it harder for licensing boards to discipline them for nonstandard practice.
Capital University of Integrated Medicine, a nonaccredited postgraduate school that closed in 2005, offered a three-day course in “Electro Dermal Resistance Analysis.” The course was said to provide “assessment of health and the treatment of imbalances of the immune system through the resistance characteristics of specific acupuncture meridians on the body” and how to “locate the systemic roots of immune system weakness and to provide stimulation to strengthen the weakness.”
Phazx Systems, which ceased operations after receiving an FDA warning letter, told prospective device purchasers: “You will be able to create a new profit center, because patients will be willingly paying for the services, as well as purchasing vitamins and supplements directly from you. Often the biofeedback testing can be billed and reimbursed through insurance companies or health plans, using biofeedback CPT codes.”
The Australian College of Allergy has concluded that “Vega testing is a technique of diagnosis without scientific basis.”  In 1997, a biomedical engineer found that placing ampules in the honeycomb of a Vegatest I device did not affect the device’s readings . This is not surprising, because glass is not an electrical conductor.
In a double-blind study, British researchers compared its results with a Vegatest device to those of conventional skin-prick testing in 30 volunteers, half of whom had previously reacted positively for allergy to cat dander or house dust mite. Each participant was tested with 6 items by each of 3 operators in 3 separate sessions, a total of 54 tests per participant. The researchers concluded that Vegatesting does not correlate with skin prick testing and so should not be used to diagnose these allergies. The authors estimated that more than 500 EDS devices were being used in the United Kingdom to assess sensitivity to potential allergens .
In 1997, Swiss researchers reported the results of a study of 32 children, ages 1.5 to 16.8 years, who received 4 to 6 weeks of hospital care for atopic dermatitis (eczema). The children were randomized according to sex, age, and severity of the skin disease to receive conventional inpatient therapy plus either”active” treatment or a sham (placebo) treatment with a bioresonance device. All of the children quickly improved. The bioresonance device had no measurable effect on the outcome variables measured in this study, which refuted the claim that it could considerably influence or even cure atopic dermatitis. The researchers concluded: “Considering the high costs and false promises caused by the promoters of this kind of therapy, it is concluded that BIT has no place in the treatment of children with atopic dermatitis.” 
In 2002, Italian researchers reported the outcome of a double-blind study that examined whether offending allergens can cause measurable variations of electromagnetic activity at specific acupuncture points. The study involved 72 individuals with asthma or hay fever and 28 healthy volunteers who were tested twice with randomly generated sequences of homeopathic dilutions of histamine, immunoglobulins, allergens, and saline (salt water) in sealed vials. The device was a DBE204. The researchers found no relation between skin conductivity changes and the type of substance contained in the vial and found wide variations in the same individual between the first and second tests of most individuals. These findings indicated that the device did not reliably determine who was allergic and who was not .
The FDA classifies “devices that use resistance measurements to diagnose and treat various diseases” as Class III devices, which require FDA approval prior to marketing. In 1986, an FDA official informed me that the FDA Center for Devices and Radiological Health had determined that the Dermatron and Accupath 1000 were diagnostic devices that posed a “significant risk.”  No such device can be legally marketed in the United States for diagnostic or treatment purposes. A few companies have obtained 510(k) clearance (not approval) by telling the FDA that their devices will be used for biofeedback or to measure skin resistance, but this does not entitle them to market the devices for other purposes.
EAV devices are not biofeedback devices. Biofeedback is a relaxation technique that uses an electronic device that continuously signals pulse rate, muscle tension, or other body function by tone or visual signal. In biofeedback, the signal originates and is influenced by the patient. In EAV, the signal is influenced by how hard the operator presses the probe against the patient’s skin. (Pressure makes the electric current flow more easily between the device to the patient’s skin.) The now-defunct International Academy of Bioenergetic Practitioners encouraged device purchasers to bill insurance companies using biofeedback codes . I believe, however, that doing this could result in prosecution for insurance fraud.
The FDA has banned importation of EAV devices into the United States and warned or prosecuted a few marketers [13.] Foreign and state regulatory agencies have also taken a few actions . However, no systematic effort has been made to drive them from the marketplace, and the FDA’s inattention to this area is disgraceful. As a result, these bogus devices are being used by many chiropractors, naturopaths, acupuncturists, dentists, “holistic” physicians, veterinarians, self-styled “nutritionists,” and various unlicensed individuals . The most common use is for prescribing homeopathic products. They are also used to determine “allergies,” detect “nutrient deficiencies,” diagnose “parasites” and organ “weaknesses,” and locate alleged problems in teeth that contain amalgam (“silver”) fillings.
EAV devices pose several serious risks. The transmittal of false or misleading health information can cause emotional harm, a false sense of security, or a false set of beliefs that can lead to unwise decisions. During the past ten years, more than 200 people have told me about their experiences with EAV practitioners. In most cases, they or someone they knew wasted hundreds (or even thousands) of dollars for the test and recommended treatment. In some cases, the person tested became very frightened and wound up undergoing expensive medical tests that showed that the diagnosed conditions were not present.
Unnecessary follow-up procedures can also be a serious problem. I know of several patients who had healthy teeth extracted after being misdiagnosed with an EAV device. In another case, a man who consulted a physician about rectal bleeding and abdominal cramps was examined only with a Dermatron and told that his colon was fine. Unfortunately, the man had colon cancer—which was not diagnosed until at least seven months later when he consulted another doctor. Two others I know about had advanced cancers were erroneously told they were cancer-free. One of them was sold 33 products to get rid of “parasites” and other nonexistent problems. One victim who tried to get a refund was told that the products had been electrically specifically modified for her and could not be used for anyone else.
The strangest report I have received came from a parent who, after reading an earlier version of this article, telephoned to described how his five-year-old daughter had been tested by an unlicensed practitioner. When the child became restless, the test was continued by probing the parent’s hand while the parent held the child. The parent also noted that the practitioner appeared to manipulate the results (seeking a “50” reading on the device) by moistening or drying the child’s finger while testing to select the appropriate remedy.
Other Device Variations
Many other “bioenergetic” devices have been claimed useful for diagnosing and/or treating health problems. I am uncertain whether or not they should be considered EAV devices or classified in some other way. The common denominator is that they rely on detection and/or manipulation of either “vibrations” and/or a body “energy” system that have no scientific recognition. The devices include the Quantum Medical Consciousness Interface (QMCI) System (also called the EPFX or SCIO), the Orion Bioscan, the Electro Interestitial Scanner (EIS), ZYTO scanners, and various Rife frequency generators.
The Bottom Line
The devices described in this article are used to diagnose nonexistent health problems, select inappropriate treatment, and defraud insurance companies. I believe that EAV devices should be confiscated and that practitioners who use them are either delusional, dishonest, or both. If you encounter any such device, please report it to the practitioner’s state licensing board, the state attorney general, the FDA, the Federal Trade Commission, the FBI, the National Fraud Information Center, and any insurance company to which the practitioner submits claims that involve use of the device. Please send copies of your complaints to me by email or by mail at 287 Fearrington Post, Pittsboro, NC 27312. You are also welcome to phone me at (919) 533-6009.
For Additional Details
- Barrett S. BioResonance tumor therapy. Quackwatch, Nov 6, 2004.
- The EAV history and roots (original method). Institute for ElectroAcupuncture & ElectroDiagnostics Web site, March 8, 1999.
- American Association of Acupuncture and Bio-Energetic Medicine. Basic explanation of the electrodermal screening test and the concepts of bio-energetic medicine. AAABEM Web site, archived Jan 28, 1999,
- Barrett S. My visit to the Nevada Clinic. Nutrition Forum 4:6-8, 1987.
- Brewitt B. Methods for treating disorders by administering radio frequency signals corresponding to growth factors. U.S. Patent Number 5,626,617, May 13, 1997. Patent Number 5,629,286 contains additional information. To access the full text of these documents, a special plug-in must be used to download them as images (click “Images” at the top or bottom of the page), a process that can take up to an hour.
- Information for e-Lybra 8. World Development Systems Web site, accessed September 4, 2007.
- Katalaris CH and others. Vega testing in the diagnosis of allergic conditions. Medical Journal of Australia 155:113-114, 1991.
- Mosenkis R. Examination of a Vegatest device. Quackwatch, Sept 4, 2001.
- Lewis GT and others. Is electrodermal testing as effective as skin prick tests for diagnosing allergies? A double blind, randomized block design study. British Journal of Medicine 322:131-134, 2001.
- Semizzi M and others. A double-blind, placebo-controlled study on the diagnostic accuracy of an electrodermal test in allergic subjects. Clinical and Experimental Allergy 32:928-932, 2002.
- Shoni MH and others. Efficacy trial of bioresonance in children with atopic dermatitis. International Archives of Allergy and Immunology 112:238-246, 1997.
- Rollings JN. Letter to Stephen Barrett, M.D., November 28, 1986.
- Bioenergetics – Space age technology available today. IABP Web site, archived Nov 8, 1999.
- Barrett S. Regulatory Actions Related to EAV Devices. Quackwatch, June 3, 2016.
This article was revised on February 14, 2018.