Accomodation
Adaptation of a nerve to a constant electrical stimulation which prevents the nerve from firing at the same level of electrical stimulation. The nerve becomes gradually less responsive to stimulation
Action Potential
Firing of a nerve with sends an electrical signal along the pathway of the nerve
Afferent
Ascending nerve that travel from the periphery to the central nervous system
Anion
Negatively charged ion that is attracted to an anode
Anode
Positively charged pole or electrode that attracts anions and repels cations
Amplitude
Maximum current or voltage delivered in one phase of a pulse; synonym for intensity
Biphasic
Waveform with two phases - one positive and the other negative; synonym for bidirectional
Cathode
Negatively charged pole or electrode that attracts cations and repels anion
Cation
Positively charged ion that is attracted to a cathode
Charge
Matter is neutral, positive, or negative; measured in units of coulombs (Q)
Current
The flow of charged particles; measured in amperes (A)
Efferent
Descending nerves that travel from the central nervous system to the periphery
Frequency
For an alternating current, measured in Hertz (Hz) which are cycles per second. For a pulsed current, measured in pulses per second (pps) Synonym for rate.
Impedance
Opposition to current; similar to resistance in physiological systems
Intensity
Maximum current or voltage delivered in one phase of a pulse; synonym for amplitude
Interphase Interval
Time between two phases
Interpulse Interval
Time between two pulses
Ion
Charged atom or molecule
Modulation
A built-in feature of some electrotherapy machines where the machine modifies the frequency, intensity, or pulse duration as the current is delivered to minimize accommodation
Off Cycle
Period of time that the current is off; measured in seconds (sec)
On Cycle
Period of time that the current is on; measured in seconds
Phase
Time that current flows in one direction. Essentially one sinusoidal, rectangular, triangular, or spike shape in one direction. For example, a rectangle with positive polarity followed by a rectangle with negative polarity has two phases and is therefore
Pulse
Time in all phases plus the interphase intervals. Essentially the pattern of shapes that continues to repeat. For example, the combination of two rectangles may be repeated. There may be a space between rectangle 1 and rectangle 2 called the interphase in
Ramp Up
Gradual increase in intensity of a current for patient comfort
Ramp Down
Gradual decrease in intensity of current for patient comfort
Rate
Synonym for frequency
Resistance
Referred to as impedance in biological systems; mathematical symbol (R); measured in ohms (?)
Time
Measured in seconds (sec) or minutes (min) for electrotherapy
Voltage
Difference in electrical potential between two points in an electrical field. The potential difference is the force which causes charged particles to move. Measured in Volts (V)