Understanding Terminology

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

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

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

ELECTRIC FIELD: A force field which defines what acceleration an electric charge placed at rest at any point in space
will feel. Electric charges cause electric fields around them, which then apply a force to any other electric charge
placed in the field.  The electric field E has both a magnitude and a direction at each point in space, and the magnitude
and direction of the resulting force on a charge q at that point is given by F= qE. When you get a shock from a door
handle after scuffing your feet on a carpet you feel the effect of an electric field accelerating electrons.

ELECTROMAGNETIC WAVE (em): Electromagnetic waves make up the electromagnetic spectrum.Visible light, ultraviolet,
infrared, radio and TV signals are all examples of "everyday" em waves.  X-rays, microwaves and  high energy photons or
gamma rays are also electromagnetic waves.

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.).

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.

MAGNETIC RESONANCE IMAGING (MRI) is a non-invasive imaging technique that uses a combination of a large magnet, radio frequencies, and a computer to generate images of internal structures and organs of the body without using x-ray radiation and surgery.

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

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

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

NMS: Neuromuscular Stimulation (used for muscle re-ed, prevention of disuse atrophy, range of motion). 

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

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.                                                                                                     
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.

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

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