Transcutaneous Electrical Nerve Stimulation, or TENS, is a non-invasive method that uses low-voltage electrical current delivered through electrodes placed on the skin to help manage pain. Peripheral Neuropathy (PN) is a condition resulting from damage to the nerves outside of the brain and spinal cord, commonly leading to symptoms like chronic pain, tingling, numbness, or burning sensations, particularly in the hands and feet. Understanding the proper placement of TENS pads is a practical step toward finding relief from the persistent discomfort associated with this nerve damage. This guide offers instructions for effectively using a TENS unit to target neuropathic pain in the extremities.
How TENS Addresses Neuropathic Pain
TENS therapy works primarily by activating the body’s natural defense system against pain signals, a concept known as the Gate Control Theory. When high-frequency electrical impulses are delivered through the pads, they stimulate the large, non-pain-carrying nerve fibers (A-beta fibers) near the painful area. This stimulation effectively closes a “gate” in the spinal cord, preventing the pain signals transmitted by smaller nerve fibers from traveling to the brain. Because the brain receives the non-painful electrical signal instead of the original pain message, the perception of pain is reduced.
A second mechanism involves the use of lower-frequency electrical stimulation, which can trigger the release of natural pain-relieving chemicals. These endogenous opioids, such as endorphins, are produced by the body and act similarly to pain medication, binding to receptors in the nervous system to inhibit pain transmission. This dual approach means TENS can offer relief through both immediate signal interference and longer-term chemical modulation.
General Rules for TENS Pad Application
For the electrical current to be effective, it must flow across or along the specific nerve pathway where the pain is located. Before applying any pads, the skin should be washed and dried to remove oils, which ensures optimal adhesion and effective electrical conduction. The adhesive pads must be placed at least one to two inches apart, but not so far away that the current cannot traverse the target area.
The goal is to bracket or “sandwich” the area of discomfort, allowing the current to pass through the affected nerves. Placing both pads directly on the precise point of pain is generally less effective than positioning them to surround it. If the initial placement does not yield a comfortable, strong tingling sensation, the pads should be carefully repositioned until the sensation is localized to the painful region. The current must never be so high that it causes pain, muscle contraction, or an uncomfortable stinging sensation.
Location-Specific Placement for Peripheral Neuropathy
Feet and Ankles
The application technique must be adapted to the size and specific location of the affected limb. For common peripheral neuropathy in the feet, a “sandwich” technique is often employed, where one pad is placed on the top of the foot and the other is positioned directly underneath on the sole. Another effective method is to place one pad near the heel and the second pad near the ball of the foot, which targets the entire foot length.
When placing pads on the ankle or foot, avoid major blood vessels. Specifically, electrodes should not be placed over the front of the ankle, where the dorsalis pedis artery is located, or over the back of the ankle, which covers the posterior tibial artery. If the neuropathy symptoms extend upward into the lower leg, one pad can be placed high on the calf muscle, and the second pad can be positioned lower toward the ankle to stimulate the long nerve path. This configuration directs the current along the nerve root rather than focusing solely on the skin surface.
Hands and Wrists
For pain and numbness in the hand and fingers, the pads are typically placed along the nerve pathway that runs through the wrist and forearm. One common placement involves putting the first pad on the center of the back of the hand. The second pad is then secured on the forearm, just a few inches below the wrist crease. This technique is designed to target the median nerve, which is a common source of neuropathic-like symptoms in the hand. Alternatively, for more specific nerve root stimulation, one pad can be placed directly on the wrist crease, aiming between the two prominent tendons.
Safety Considerations and Unit Settings
Before beginning TENS therapy, a consultation with a healthcare provider is recommended to ensure the treatment is appropriate for the specific condition. TENS pads should never be placed near the heart or across the chest, over the front of the neck, or on any areas of broken or irritated skin.
Electrical stimulation should also be avoided over areas with metal implants or where sensation is completely absent, as the inability to feel the current makes it difficult to adjust the intensity safely. For chronic neuropathic pain, the most common setting involves using a high frequency, typically between 80 to 120 Hertz (Hz), combined with a low intensity. This setting is best for continuously activating the Gate Control mechanism to block pain signals.
Some users find relief by alternating to a low-frequency setting, around 2 to 10 Hz, which is believed to maximize the release of the body’s natural opioid peptides. Regardless of the frequency used, the intensity should always be adjusted slowly until a strong, buzzing, but entirely comfortable tingling sensation is felt. If the sensation becomes painful or causes muscle twitching, the intensity must be immediately reduced.