Reinhold Voll was a physician and acupuncturist, an unusual mix of genuine and counterfeit medicines. In the 1950s, the doctor embraced his Mr. Hyde persona and created a device that purportedly utilized skin resistance as a means to determine the health of internal organs.

His machine and those like it have undergone various alterations, keeping up with technology so that the testing is now mostly done by computer. But despite this seeming evolution, the mechanism remains as implausible as it did when Voll introduced his device 60 years ago. Nor is there any more reason to believe in the existence of meridians, which play a central role in Voll’s invention.  

Clients hooked up to these galvanometric machines are given a quick and thorough reading about their supposed state of health. Stephen Barrett of Quackwatch gave it a go and documented his experiences in an article for Skeptical Inquirer.  

These electrodermal screening devices are said to measure skin resistance to the  passage of low-level electrical currents. A probe touches a specific point on the patient’s skin, prompting the machine to produce a readout from zero to 100. Voll explained that readings from 45 to 55 were normal, or “balanced” in alt-med lingo. Readings above 55 indicated inflammation of the organ associated with the meridian being measured, while readings below 45 suggested “organ stagnation and degeneration.” Homeopathic products were then given to the patient until he or she was said to be balanced. But as Barrett learned, the same skin location can produce wildly varying numbers within the same session. Also, there is no known mechanism that would enable the machine to do what its inventor claimed. Therefore, the seeming balance restorations were really just the machine giving inconsistent, meaningless information.

With modern incarnations, the client holds a metal bar in one hand while the operator applies a probe to a supposed meridian on the client’s free hand. As the SkepDoc Harriett Hall noted, it is supremely convenient for testing purposes that all meridian points are on the hands or feet.

Meanwhile, Barrett, described his experience with the device thusly: “During the testing, I noticed that the harder the probe was pressed against my skin, the higher the reading on the computer screen, which is not surprising because pressure reduces electrical resistance and makes the current flow better from the probe to the skin. Also, glass does not conduct electricity, so even if the products emitted electric signals, they could not escape from the vial.”

Additionally, there were huge signs of fraud during Barrett’s session. He noted that even though his gallbladder has been removed, the machine still gave a readout indicating this organ was “out of range,” though that was later upgraded to within range in a subsequent test that day, then downgraded again.    

Some versions of the machines even give food recommendations, though these are also terribly inconsistent. In many instances, some foods are listed as both ones to avoid and enthusiastically consume. This is similar to some edibles ending up on both superfood and supervillain food lists, though this is worse since the same source is recommending both eating and eschewing them. Such completely contradictory and inconsistent results show the device is incapable of measuring what it claims.

According to Barrett, to demonstrate that a device can detect organ pathology, it is necessary to conduct double blind controlled studies of people who have the condition and people who do not. Extrapolating this, demonstrating that administering a product or procedure can mitigate an illness or conditions requires studying whether people who are treated do better than those in the control group.

But with Voll’s device, screeners can offer no explanation how it determines organ health by means of a never-explained concept called meridians. There is no justification for how, say, the tip of the right index finger would tell if someone was at danger for cirrhosis. Nor is there any evidence that skin resistance is related to organ health or what people should eat. It’s no wonder Hall compared the galvanometer to a Magic 8-ball for its randomness and lack of medical genuineness. Indeed, all these machines can do is generate a small electrical current, a stimulus that is incapable of providing information on organ health, which would explain why the readings for the same client during the same session were so inconsistent.

Still, the field has its defenders. Hans Larsen at yourhealthbase.com touts the galvanometer as being able to provide “an in-depth health assessment and treat many problems right on the spot with electrical impulses. ”

He chastises “conventional Western medicine” for looking for “structural defects” that may lead to surgery or drugs.  He then asks, “Why don’t we focus on modifying our thoughts and other subtle energies in order to heal ourselves?”

I don’t know what subtle energies Larsen is referring to, so I cannot attempt to procure them. But I can control what I’m thinking, and I conclude that Larsen’s recommendation of treating diseases with thoughts and undefined energies instead of doctors and medicine is a poor one.