Shinobi

I'm doing an a presentation for a class in which we discuss the merits and uses of a particular piece of technology used in the fitness/health industry. The other guy in my group believs in chi and accupuncture, and wanted to do a machine that supposedly detects meridian lines. We discussed it and he will speak about the device, then I will present a skeptical critique of the device. This is cool as I will get the chance to show the class some scepticism in action.

Anyway the device is called an Electrodiagnostic device and is detailed here:

http://www.quackwatch.org/01Quackery...s/electro.html

and here: http://www.canoe.ca/HealthAlternativ...ns/000524.html

does anyone know anything about these devices or know any other sites with info?

Tat

Specifically regarding the devices, you might check JREF. James Randi does occasionally look at one of these devices. Check out his commentary archive.

By the looks of it, these devices are similar to the famous Scientology E-Meter, well described as a crockpot device.

Debunking this is not likely to be easy. Your discussion partner may parrot claims made on the manufacturer's website, and these will be tough to refute. Sure, you can claim they are of a questionable source, but if you can't find a claim that shows it is false, poor or unreliable data is more convincing than no data. And if you can show one device is flawed, it is perfectly easy to say "sure there are frauds, but how about this other device."

You may want to get a list of the devices your partner thinks have the properties mentioned before the debate. Focus on reseaching those devices specifically.

Hatchet

Debunking these sorts of things is hard because they make a very general claim which is that making resistance measurements of the body at certain points can diagnose various diseases.

The first thing to make very clear is that it is up to the person making a claim to prove their case. What reputable double-blind* experiments have been done to establish that these claims are true? Perhaps some people have done such a test and you can present the results.

As a demonstration of how these machines work, you could take a standard ammeter (or a volt meter that has a resistance measurement setting. Almost all do). Set it to it's most sensitive setting and get someone to hold one of the meter probes in their hand. Put the other probe on these so called meridan points and demonstrate how you get a different reading at each point. It doesn't prove these devices are fake, but it does show how you can mimic the results with a $20 general purpose electronic tool.
You could also ask the person to jump up and down a few times after taking the first reading (if they sweat a little it will increase conductivity on the skin) and take a second reading to show how you get a different reading.


Point to the fact that these devices aren't approved for medical diagnosis (supporters will argue it is a conspiracy theory).

Point out that there is a lack of properly controlled double blind studies supporting the claims made for these devices. (supporters will say that there is an overwhelming amount of anecdotal evidence. Scientists are biased. They will also probably point to ill-conceived and improperly controlled experiments).

How were the 80 (or more) meridian points determined? Surely a large study must have been done to correlate the various diseases to these points? Can your opponent point to any?

Point out that while yes there is an effect (which you can demonstrate using the above technique), all you are doing is measuring resistance. You can get the same effect by measuring a potato, does that mean you can also detect diseases in potatos?

Point out that there is no evidence that electrical conductivity on the skin is any indicator of disease.

As a last though perhaps you can find a site that has a circuit diagram for one of these machines and show how similar it is to a simple ammeter.

ttfn

* By double blind I mean that you should select a group of people with a known medical condition to be tested for, and a group of patients that do not have the condition. The patients from both groups should be randomly assigned to one of two groups (Group A and Group B). So both Group A and B will contain a mix of patients with and without the disease. Group A is tested with the real machine and group B is tested with a fake machine (or perhaps with a real machine, but different "meridian points" are measured). The patients should not know which machine they are being tested with and the experimenters should not know which patients have the disease. Once the experiment is complete, the test results are matched up to each patient to see how accurately the "real" machine diagnosed the disease vs the "fake" machine.

anakata

Regarding the functioning of E-meters: http://www-2.cs.cmu.edu/~dst/Secrets/E-Meter/

Biff the unclean

You should pick up a copy of QUACK!: Tales of Medical Fraud from the Museum of Questionablr Medical Devices it's by Bob McCoy and is in trade paperback

seebs

I have met Bob McCoy!

In fact, he performed my marriage. Great guy.