OMNIVERSA
®
MULTI-MODALITY THERAPY USER MANUAL - 89 -
COPYRIGHT © 2017-2020, ACCELERATED CARE PLUS CORP., ALL RIGHTS RESERVED
Low Voltage Pulsed Currents (Biphasic)
Asymmetrical, Symmetrical and Alternating Asymmetrical Biphasic
The biphasic pulsed current family of waveforms are often used in TENS (Transcutaneous Electrical Nerve
Stimulation) and NMES applications. These waveforms are characterized by variable phase duration and variable
pulse frequency. In an asymmetric biphasic waveform, the typical amplitude, duration, and rate of rise and decay are
unequal for each phase with respect to the baseline, however the waveform is fully balanced, i.e. the phase charges
of each phase are equal.
A variation to the standard biphasic asymmetrical pulsed current is the alternating one, in which the successive pulse
phases alternate with respect to the baseline.
The symmetrical biphasic mode provides the same amplitude, duration, and rate of rise and decay for both the
positive and negative phase of the waveform. This is often used to stimulate larger muscle as both phases have equal
intensity.
To prevent accommodation to stimulation or to improve patient tolerance, the pulse duration can be varied through
modulation.
Parameters:
Phase Duration, expressed in µs, is the elapsed time from the beginning to the end of one phase of a pulse.
Interphase interval, is the duration between two consecutive components of a pulse where no electrical
activity occurs.
Pulse duration, is the time from all the phases of a pulse and interphase interval (expressed in sec)
Interpulse interval – the time between two successive pulses.
Pulse Frequency, expressed in Hz or pps (pulses per second), defines the repetition rate of the biphasic pulses.
Phase Duration Modulation, expressed in percentage, defines a variable phase duration range that can be
swept between the upper and lower limit over a variable time.
Rate Scan, expressed as a percentage sets the fluctuating Phase Duration range.
Rate Scan Time, is the duration or how long it takes to cycle through the modulation upper and lower limit
range during Phase Duration Modulation
Burst Symmetrical
The burst biphasic symmetrical pulsed current is a variation to its non-burst counterpart, in which the continuous
train of pulses is interrupted by pulse pauses. A burst frequency can be set for motor stimulation, where the use of
continuous stimulation with a low pulse frequency would be too painful. Each burst lasts for 100ms and the burst
rate can separately be adjusted. With this milder LVPC waveform, it is easier to exceed the motor threshold
stimulus.
PENS
PENS uses an asymmetric biphasic waveform. The typical amplitude, duration, and rate of rise and decay are
unequal for each phase with respect to the baseline, however the waveform is fully balanced (i.e. the phase charges
of each phase are equal). A narrow pulse duration is used (70 sec) to avoid stimulating nociceptors. The two
channels are timed and modulated to replicate basic EMG and functional EMG patterns for neuromuscular re-
education and treatment of muscle disuse atrophy.
To Next Page
Loading...
