What is electrotherapy?

Electricity has been used to treat pain for over 100 years. Early proponents of electricity were labeled as charlatans, but recent scientific studies have proven that electricity can reduce both acute and chronic pain. The exact mechanism of electrical stimulation’s beneficial effect remains controversial. Electrical stimulation may directly block transmission of pain signals along nerves. In addition, electrical stimulation has been shown to promote the release of endorphins, which are natural painkillers produced by the body.

Several different electrical stimulation devices exist, each producing different frequencies, waveforms, and effects. Electrical modalities include

• Transcutaneous Electrical Nerve Stimulation (TENS) (the most commonly used)
• Interferential Current (IFC)
• Galvanic Stimulation (GS)

Common characteristics of electrotherapy stimulation

TENS, IFC, and GS all apply electrical stimulation to nerves and muscles via adhesive pads placed on the skin. These devices are powered by batteries, and some units have an adapter that allows powering from an outlet. Side effects are rare, but include allergic skin irritation under the adhesive pads and transient pain from the electrical charge. Placing the pads over the heart or over pacemaker leads could conceivably cause cardiac arrhythmia; placing them over the throat could conceivably cause low blood pressure; and placing them over a pregnant uterus could conceivably cause fetal damage. Because of these risks, electrical stimulation over these areas should be avoided. Electrical stimulation should also not be applied over malignancies.

Transcutaneous Electrical Nerve Stimulators (TENS)

Characterized by biphasic current and selectable parameters. Stimulates sensory nerves to block pain signals, stimulate endorphin production, or, in the case of the SMP™, to help normalize sympathetic function distal to the electrodes.

COMMON USES: Acute and chronic pain, back and cervical muscular and disc syndromes, RSD, arthritis, shoulder syndromes, neuropathies, and many other painful conditions.

Interferential Current (IFC)

Characterized by the crossing of two medium, independent frequencies which work together to effectively stimulate large impulse fibers. These interfere with the transmission of pain messages at the spinal cord level. Because of the frequency, the IF wave meets low impedance when crossing the skin to enter underlying tissue. The deep tissue penetration can be adjusted to stimulate parasympathetic nerve fibers for increased blood flow.

COMMON USES: Pre and post orthopedic surgery, joint injury syndrome, cumulative trauma disorders, increasing circulation and pain control of various origins.

HOW IF DIFFERS FROM TENS: Deeper penetration with more comfort (compliance) and increased circulation.

Galvanic Stimulation (GS)

Characterized by high volt, pulsed galvanic stimulation, used primarily for local blood flow stimulation through muscle pumping and through the “polarity effect.” Excessive fluid is comprised of negatively charged plasma proteins which leak into interstitial spaces. By placing a negative electrode over the site and a positive electrode at a distant site, the monophasic high voltage stimulus applies an electrical potential which disperses the negatively charged proteins away from the site, thereby helping move the excess fluid.

COMMON USES: Maintain or increase range of motion of small muscles, prevent disuse atrophy and muscle re-education of small muscles, increase circulation and prevent venous thrombosis. Post-op orthopedic surgery, pain control, sprains and strains and degenerative joint disease are other common indications.

HOW IT DIFFERS FROM TENS: Pulsed direct current vs. alternating current; able to use in water bath (immersion technique) and increase local blood flow.