CriterionMed

Electrotherapy

Electrical conduction through biological systems has been recognized for centuries to alter physiological and pathologic events which result in pain relief. Recently, science has discovered many additional deficiencies respond favorably to electrical stimulation:

Limb swelling and inflammatory reactions.
Slow-to-heal wounds and ulcers.
Muscle atrophy and impaired motor control associated with orthopedic and neurological damage.
Circulatory impairments.
Joint motion dysfunction.
Postural disorders.
Incontinence associated with pelvic floor incapacity.

Electrotherapy Basics

The following section and accompanying modality pages with treatment protocols are designed to direct clinicians toward a sound, systematic, objective, and predictive approach to electrical stimulation.

Currents:

In the field of physical medicine and rehabilitation, electrical stimulators are classified as the following:

Direct Current (DC):Electrical current that flows in one direction for about 1 sec or longer.
Alternating Current (AC):Electrical current that changes the direction of flow, with reference to the zero baseline, at least once every second.
Pulsed Current (PC):Electrical current that is conducted as signals of short duration. Each pulse lasts for only a few micro or milli-seconds followed by an interpulse interval.

Waveforms:

The shape of the electrical current:

Monophasic:Indicates that there is only one phase to each pulse.
BiPhasic:wo opposing phases are contained in a single cycle.
1. Symmetrical:Same size and shape for each phase in both directions.
2. Asymmetrical:Uneven size and shape for each phase; when balanced the net charge is equal in both directions.
Amplitude:Intensity is the output of electrotherapy distributed by the unit to the patient. Depending on the waveform, intensity is measured in milliamps (mA), volts (V), and microamps (μA); affects the muscular response - higher intensity = increase excitability.
Pulse Duration/Width:Indicates the length of time the current is flowing per cycle; affects patient comfort.
Pulse Rate/Frequency:Indicates the number of pulses or cycles per second; affects the quality of contraction and can create muscle fatigue at higher rates.
1. (A) Indicates Pulse Width/Duration.
2. (B) Indicates Interpulse Interval.

Current Modulation:

Refers to any variation in the amplitude, duration, frequency of the current during a series of pulses or cycles; designed to prevent accommodation.

Continuous:Current flow remains the same.
Burst:A series of pulses at a predetermined pulse frequency.
Cycle Time:(Duty Cycle) On/Off stimulation; affects the fatigue rate.
Ramp:Current amplitude will increase (ramp-up) gradually to some preset maximum and may also decrease (ramp-down) in the intensity; controls for patient comfort.
Sweep:Variation of frequency, typically associated with Interferential Devices.
Pulse Width Modulation:Variation in pulse duration over predetermined period.
Pulse Rate Modulation:Variation in pulse frequency over predetermined period.

Polarity:

During the use of any stimulator, an electrode that has a greater level of electrons is referred to as negative (attracts positive ions). The other electrode has a lower level of electrons and is referred to as positive (attracts negative ions).

AC Waves:Electrodes change the polarity with each current cycle.
DC Waves:The therapist can designate one electrode as negative and the other as positive. For the duration of the treatment, the electrodes will provide that designated polar effect: positive can constrict blood vessels, reducing edema; negative can dilate blood vessels, increasing circulation.

Stimulators:

TENS:Transcutaneous Electrical Nerve Stimulation is device designed to stimulate sensory nerves for the relief of chronic, arthritic and post-surgical pain.
NMES:Neuromuscular Electrical Stimulation device is designed to stimulate motor nerves for disuse atrophy, muscle spasms, and improving range of motion.
HVPC:High Volt Pulsed Current device has a very brief pulse duration characterized by two distinct peaks delivered at high voltage. The waveform is monophasic and causes a decreased skin resistance making the current comfortable and easy to tolerate. This device is designed to reduce edema (swelling) and relieve chronic, arthritic and post-surgical pain.
IFC:Interferential Current is distributed through two channels (four electrodes). The currents cross each other in the body at the area requiring treatment. The two currents interfere with each other at this crossing point, resulting in a modulation of the intensity (the current intensity increases and decreases at the beat frequency). This device is designed to stimulate sensory nerves for the relief of chronic, arthritic and post-surgical pain.
MENS:Microcurrent Electrical Nerve Stimulator is a monophasic waveform of very low intensity that closely simulates the electrical current generated by the human body designed for the relief of chronic, arthritic and post-surgical pain.