Electrotherapy Glossary

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

ALTERNATING CURRENT Current that flows in one direction then reverses; therefore the waveform has two phases with zero net DC.

AMPLITUDE (Intensity): The level of output current produced by a unit. Typically given in milliamperes peak (thousandths of an ampere < mA > ). Constant current unit's voltage varies to deliver required current to electrodes.

back to top

BURST MODE A series of higher frequency pulses delivered in bursts at a low rate. Designed for patient comfort and is sometimes substituted for acupuncture-like TENS.

back to top

CONSTANT CURRENT The ability of a device to keep its voltage constant over any load resistance. Higher impedance will lower voltage. Lower impedance will heighten voltage.

CONSTANT VOLTAGE The ability of a device to keep its current constant over any load resistance. Higher impedance will lower current. Lower impedance will heighten current.

CURRENT The flow of charged particles past a given point per unit time. Positive current flows from positive to negative. Measured in "milliamps" (mA).

back to top

DIRECT CURRENT Current that has no change in the direction of flow.

DUTY CYCLE (Control found on NMS units): Stimulation ON-OFF times to maximize muscle contraction and minimize fatigue.

back to top

FARADIC CURRENT Alternating current (A/C) biphasic current designed to deliver no DC current to the patient's body. Used for pain control and NMS.

FREQUENCY (Rate): The fequency of a signal in pulses per second (Hertz or Hz.).

back to top

GALVANIC STIMULATION Direct (DC) or monophasic current which delivers electrical energy (net DC) to the patient's body. May be delivered in pulsed form. Mainly used for edema reduction and and increasing or decreasing circulation in a specific site on the body.

back to top

IMPEDANCE A substance that impedes the flow of current (skin, fat etc.) Sometimes referred to as "resistance". Measured in "ohms". Ohm's Law: Current = Voltage/Impedance

back to top

MICROCOULOMB The total energy in a pulse. Typically the amplitude (mA) x the width (µsec.).

MICROCURRENT (Microamperage, MENS): Uses low output wide pulse width. Output current is usually less than 600 microamps. Indications of success are largely anecdotal.

MODULATION MODE Automatic cyclic change in waveform parameters (frequency, pulse duration, and/or amplitude) designed to prevent accommodation.

back to top

NMS (FES, NMES, EMS, Muscle Stim): Neuromuscular Stimulation (used for muscle re-ed, prevention of disuse atrophy, range of motion). NOTE: FES or Functional Electrical Stim is similar.

back to top

PULSE DURATION (Pulse Width): The measure of time duration of a pulse. Usually indicated in microseconds (millionths of a second, or µsec. ).

back to top

RISE TIMES/DECAY TIMES (Control found on NMS units): Ramps amplitude of stimulation current, both up and down, to improve user comfort and thus encourage compliance.

back to top

STRENGTH DURATION MODE Utilizes a stimulation signal which tracks the Strength Duration (SD) curve. The SD curve is a family of curves -- on for each nerve type which relates the nerve firing threshold to the amplitude and pulse width of the stimulating signal.

back to top

TENS (TNS, TES): Transcutaneous Electrical Nerve Stimulation. (Used for pain control.)

Learn more about how TENS works.

back to top

VOLTAGE The driving force for charged particles, measured in volts.

back to top

WAVEFORM A pictorial representation of stimulation signal as seen on an oscilloscope. Usually seen as amplitude (current) vs time (sec).

back to top