In 1825, a French physicist named Salandière was the first person to pass an electric current through acupuncture needles. But, for lack of scientific validation, the interest it aroused among his contemporaries was rather weak. However, the idea resurfaced in 1958 in Shanghai. Doctors have already successfully used acupuncture to relieve postoperative pain from tonsil removal by stimulating the He Gu (4 GI) point on the back of the hand. However, to have a good effect, the stimulation on the needle had to be strong and continuous for at least 20 minutes, which can be quite laborious. It was to make this treatment technique easier that the Chinese made a device that would produce electrical stimulation on acupuncture needles to replace manual stimulation.

In 1965, two renowned researchers, psychologist Ronald Melzack and physiologist Patrick Wall, unrelated to acupuncture, discovered that certain electrical stimuli on the skin effectively relieved pain. They named their technique “transcutaneous electrical nerve stimulation”, more generally called TENS. It is commonly used in hospitals and physiotherapy clinics to relieve various acute and chronic pain.

The technique involves placing electrodes on the skin at the location of the pain; relief is provided by non-painful stimulation which, through the nervous system, inhibits conduction of the pain message. This neurophysiological process is the same that occurs when you rub or massage yourself lightly for pain relief. To give good results, the stimulation must be of high frequency (usually around 100 hertz), of low intensity (well below the pain threshold) and of a fairly long duration (more than 30 minutes).

In 1975, Melzack worked on the application of electricity to acupuncture needles (TENS-acupuncture) and discovered its mechanisms of action. Today, TENS-acupuncture is widely used and gives good clinical results in the face of pain.

In TENS-acupuncture, the electrodes or needles are generally placed on an acupuncture point corresponding to the painful area, but often far from it (called the distal point). TENS-acupuncture creates stimulation at low frequency (between 2 and 10 hertz), at high intensity (close to the pain tolerance threshold) and of relatively short duration (between 15 and 30 minutes). This type of analgesic stimulation is called diffuse inhibitory control induced by noxious stimuli (CIND). In this case, the painful stimulation produces counter-irritation analgesia. This neurophysiological process of relief is the same that explains why vigorous massages, cupping, cauterization, bleeding, and strong methods work.

Recent scientific research has shown that TENS-acupuncture acts through endorphins, substances similar to morphine, secreted by the pituitary gland, which have euphoric and analgesic effects, and which inhibit the transmission of health messages. pain.

Most of the time, acupuncturists use electrical stimulation devices to combat pain. But they are also used to treat all kinds of other ailments when you want to get a stronger stimulation than that obtained by simply handling the needles.