Electrical Pulse Parameters Flashcards
components of naming current
balanced or unbalanced
symmetry/asymmetry
shape
alternating/mono/bi current
balanced current
area under each pulse on a graph is symmetrical
shape may be different but if area under each is the same it is still balanced
alternating current
current flows in both directions on a circuit
eg wall outlet, changing directions many times a second
direct current
current flows one direction in a circuit
eg: battery
phase
current flowing in one direction for a definite amount of time
eg: only positive part of biphasic pulse
phase duration
time from beginning of one phase of pulse/cycle of alternating current
pulse duration
time from beginning to end of one pulse
interphase interval
period of time of no electrical activity between two phases
what does lengthening duration of phase do to fiber recruitment?
it increases recruitment due to longer time for the electricity to meet capacitance of tissue
current density and electrode size
smaller electrodes will deliver greater current density and higher stimulation intensity due to the same amount of voltage being spread over a smaller area
too small electrode can lead to harmful densities and damage tissue
rise time
time for leading edge of phase to increase from zero to peak amplitude
decay time is opposite
amplitude modulation
variation in peak amplitude among pulses (mA)
phase/pulse duration modulation
vary phase or pulse duration in a series of pulses (ms)
frequency modulation
vary frequency among pulses
duty cycle
ratio of on time to the total time of stimulation, expressed as percentage
burst
series of pulses or cycles of aAC delivered during the ON period of the stimulator
burst duration
length of time of burst in ms bc many combined pulses
burst frequeny
bursts per second
direct current
current running for one second or greater in one direction
alternating current
continuous bidirectional flow
symmetrical (most are this)
asymmetrical (creates polarity, uncommon)
IFC and russian are AC
IFC actual current name
medium frequency beat/ampltiude modulated alternating current
russian actual current name
medium frequency burst/time alternating current
how does IFC work?
two sinusoidal AC currents differing in frequency
where the frequencies intersect they summate, resulting in higher or lower amplitudes
creates beats of varying amplitudes
rms of current
root mean squared
area under the curve is how much current pt is getting
need to be able to metabolize and disperse heat from current transferring energy to tissue
uses of IFC
as TENS: pain management, other applications liek joint mobs/ROM
decrease chronic edema
what is IFC not good for?
not good for use with small electrodes due to high RMS, however if machine is constant voltage generator is better
not good for generating polarity like acute edema or wound healing
uses of russian current
regain muscle strengtgh with strong enough force
regain ROM if strong enough contraction
decrease chronic edema
russian current is not good for:
not good for use with small electrodes due to high RMS, however if machine is constant voltage generator is better
not good for generating polarity like acute edema or wound healing
pulsative current
noncontinuous flow of direct alternating current
types: HVPC or monophasic, biphasic, polyphasic
HVPC
twin peak pulses with monophasic PC current
pulse duration: 5-20 usec, very short
amplitude: 2000-2500, very high
RMS is low due to short duration with high amplitude
uses of HVPC
create weak polarity due to monophasic wave
can excite sensory, motor, and pain fibers due
+ disuse atrophy, chronic edema
HVPC should not be used for:
large muscle groups
denervated muscle
iontophoresis, which requires a stronger polarity
calculate current density
current / area of electrode
high RMS currents
russian
IFC
must be used with larger electrodes
low RMS currents
monophasic pulsed current
HVPC
biphasic symmetrical pulsed current
