TENS Units

[jollyrgr]

Any doctors out there? I want to know about TENS units. More specifically the things that use electrical stimulation for musle relaxation or massages as a pain reducer. (Sometimes these are sold as a NO WORK exersize unit; but that is a different thread.) Today I saw one at a health fair setup at work. It looked like an overgrown ladybug; about the size of large softball. It had two wires that connected to medical contacts; the tape with the metal connector on it for attaching sensors for EKG, EEG, etc. I had not seen the sensors and saw that the thing was labeled as a "massager". (I'd thought the wires led to a remote.) The seller came over and described it as "It works like a TENS unit". I've seen TENS units in the OR and there use was described to me as being used to reduce post surgical pain.

My question is this: Are these "QUACK" devices that work like a placebo? In other words a patient is told "This will reduce pain" they feel the musle twitch, they assume it works, mind blocks pain.

Why I ask is in my entire life I have been told of several things for injuries:
Medication like Tylenol, aspirin, etc. reduces pain.

ICE: Bumps/Bruises are to be iced. Works when heavy objects fall on a foot or hammer misses its mark.

Heating pad: When the hammer or heavy object misses real bad and a bone is broken or fractured. Also works for sore back.

[bodgy]

EPE magazine did some home build projects a year or so ago on TENS units.


Colin

[zotdoc]

TENS units, Trans- cutaneous Electric Nerve Stimulators, work by applying a small electrical "shock" to the areas with the stick on electrodes. It seems that pain stimulae are sent by the peripheral nerve endings to a synapse (nerve connection) at the spinal cord level, where the signal is translated and sent to the brain, and is then experienced as pain. There is a certain latency period at the spinal cord level and there is also some crossover from the various sensory inputs, heat, cold, touch, position, pain. The theory is that the electrical stimulus to the nerve endings in the skin, even mild ones, somehow overload or block the "gate" at the spinal cord and thus lessen the perception of pain. As a surgeon I have used these many times, and they do seem to reduce the amount of pain post operatively, but never to the point of being pain free.
They also can reduce the amount of back pain if properly placed, but again, they probably won't ever replace medication, just supplement it. I have given many injections that the patients say are pain free, because I always touch the needle to the skin just a fraction of a second before actually inserting the needle, and I think this is because of the "gate" latency. The latency is why you feel more pain a few instants after cutting yourself than you do right when the cut happens. The patients feel the touch but then can't feel the stick! I hope this answered your question, I know I've sort of rambled!

[Chris Smith]

I know two people who were issued these units from a chiropractor, neither worked at all to help either of them.

It stimulates, it was addictive, but it was completey bogus to help.

Expensive as well?

[k7elp60]

I agree that a tens unit may heal the pain, but I have seen them help with the endurance of pain. I have built a number of experimental units. The reason the commercial ones are expensive is that they require FDA approval to be on the market. But a doctors prescription to a durable medical supply house can sometimes off set the cost. If the electrodes are positioned properly they certainally reduce the pain. I know of a fellow that published a circuit for one in a trade magazine, and was hounded by the government for a long time. The ones I have built were
essentially reverse engineered from working units.

[ringo47stars]

I recently read a book on the subject or more like a sci-fi book about the use of wireheading by a female. Instead of stick on electrodes they had a plug in the head but they almost had a patent on an inductance method in the time frame of the book(1994 to 1999). It was called Mindkiller by Spider Robinson.

[Dave Dixon]

Off topic, but Spider rocks. I just reread that one a few months ago. It had been on my bookcase since the early 80's!!!! Regards,
Dave