Frequently Used Modalities
Transcutaneous Electrical Nerve Stimulation
A Transcutaneous Electrical Nerve Stimulator is primarily used for managing chronic pain. It utilizes biphasic electrical current delivered through electrodes placed on the surface of the skin to stimulate the sensory nerves to block pain signals and help the body’s endorphin production (its natural analgesic). TENS can be worn all day or on an as needed basis.
Common device features include adjustable pulse rate, pulse width, and amplitude (intensity). Higher priced units offer modulation (variations) of pulse rate, width, and/or amplitude settings, and other user friendly features.
Most TENS units will utilize an asymmetric waveform which is more comfortable than other waveforms such as symmetric or monophasic. TENS units offering “Strength Duration” modes help normalize sympathetic function distal to the electrodes. Placement of electrodes are usually at pain site or along the nerve channels, called dermatomes.
TENS devices are the most often prescribed modality in electrotherapy. These devices are easier to use than other modalities. A TENS unit is not the same as other electrical stimulators (e.g., neuromuscular stimulators) which are used to directly stimulate muscles and/or motor nerves.
Neuromuscular Electrical Nerve Stimulation
Primarily used for preventing disuse atrophy (muscle wasting), NMES is stronger than a TENS unit with a wider pulse width to elicit muscle contraction for a period of time. More than just nerve stimulation, muscles are contracted and relaxed on and off to strengthen muscles, increase blood circulation to the area, and/or to reduce edema. Device features include adjustable pulse rate, width, amplitude, ramp, alternating or synchronous stimulation. Higher priced devices offer accessory jacks for remote switches, AC adapters, and other user friendly features. Electrode placement is very important, mostly over motor points or on the belly of muscles.
Primarily used to manage deep chronic pain, Interferential current uses very high pulse rate, usually 4001 – 4150 pulses per second. Device features include adjustable pulse rate, two or four electrode treatment selection, and modulation of pulse rate. Because of such frequency, these devices will require a lot of power, and thus, batteries will not last long. AC Adapters are usually provided with device. Electrode placement should be in an “X” pattern, as the point of intersection provides a third stronger frequency.
- Relaxation of muscle spasms
- Prevention or retardation of disuse atrophy (wasting of muscle due to lack of use)
- Increasing local blood circulation
- Muscle re-education, such as after surgery or trauma
- Maintaining or increasing range of motion or joint mobility
- Preventing venous thrombosis (blood clots due to inactivity) immediately following surgery
- Post-orthopedic surgery
- Joint replacement (i.e. hip, knee, shoulder)
- Muscle strengthening programs
- Shoulder subluxation
- Reduction of muscle spasms