Transcutaneous electrical nerve stimulation (TENS or TNS) is the use of electric current produced by a device to stimulate the nerves for therapeutic purposes. TENS, by definition, covers the complete range of transcutaneously applied currents used for nerve excitation although the term is often used with a more restrictive intent, namely to describe the kind of pulses produced by portable stimulators used to treat pain. The unit is usually connected to the skin using two or more electrodes. A typical battery-operated TENS unit is able to modulate pulse width, frequency and intensity. Generally TENS is applied at high frequency (>50 Hz) with an intensity below motor contraction (sensory intensity) or low frequency (<10 Hz) with an intensity that produces motor contraction. While the use of TENS has proved effective in clinical studies, there is controversy over which conditions the device should be used to treat.
What to Expect with TENS Therapy
TENS therapy typically uses electrodes on small, sticky pads attached via wires to a battery-operated device. The electrodes are placed over the area in pain, and current is sent through the electrodes, stimulating the sensory nerves and creating a tingling sensation that reduces the feeling of pain.
A hand-held controller allows the individual to select from a range of options, such as high frequency or low frequency current as well as complex patterns of stimulation.
People are often introduced to TENS therapy during physical therapy or in a chiropractor's office. This gives the individual the opportunity to see whether pain relief is sufficient to consider purchasing a TENS unit for home use.
In recent years, a number of TENS products have been marketed as wearable devices. Some of these devices deliver current directly from electrodes in a battery-powered unit worn on the body. The unit may be strapped to a leg or attached to the back, shoulder, knee, or other part of the body. These devices are typically not visible under clothing.
Therapy may be done in 30-minute segments or run continuously. Overnight therapy is possible in some cases.
The response to TENS varies widely. While many individuals consider TENS a key part of their treatment, TENS does not relieve pain for everyone.