E stim Flashcards
which body structure is the best electrical conductor?
blood
which body structure is the poorest conductor?
bone
which body structures are good conductors?
blood
nerve
muscle
which body structures are poor conductors?
skin
fat
tendon
bone
what is intensity?
stimulation or amplitude
what is pulse duration?
current pulse length
changed to target specific structures
what is capacitance?
the ability of tissue to store electricity
in what order are neurons stimulated from least capacitance to highest?
AB
AD
C
muscle fiber
muscle tissue
when turning the amplitude up on an e stim unit, what is the order in which nerve are stimulated?
AB (tingle feeling - sensory only)
motor
AD (stimulated with chronic pain)
C (dull pain)
denervated muscle
what are the pain relieving e stims?
IFC
Tens
what frequency does tetany occur at?
50 pps (Hz)
where is the site of depolarization?
cathode
what is the waveform for NMES or FES?
pulsed at 1-500 hz
what is the waveform and frequency for Russian currents?
pulsatile biphasic
2,000 - 10,000 hz
what is the waveform for interferential currents (IFC)?
interfered biphasic continuous
1,000 - 10,000 hz
what is the waveform for high-volt pulsed current?
twin-peaked pulsed waveform
what is the waveform for transcutaneous electrical nerve stimulation (TENS)?
asymmetric biphasic currents
what is low-volt current (DC) used for?
iontophoresis
where is the electrode placed for strengthening e stim?
at the motor point
motor point is where the threshold is the ___ for a given electrical input
lowest
what are the main uses of high-volt currents?
reducing edema
wound healing
conventional TENS:
____ rate
____ intensity
best for ___ pain
theory?
high rate
low intensity (sensory level)
acute
gate control theory (stimulate AB)
acupuncture-like TENS:
____ rate
____ intensity
best for ___ pain
theory?
low rate
high intensity (motor level)
chronic
descending pain control theory (release of enkephalin)
noxious-level TENS:
________ analgesia
theory?
hyperstimulation
endogenous opiate pain control theory
brief intense TENS:
____ rate
____ intensity
best for ___ pain
theory?
high rate
high intensity
fast pain relief during wound debridement
peripheral and central analgesia
conventional TENS:
frequency:
duration:
time:
theory:
frequency: 80-125 pps
duration: 70-150 microseconds
time: 30mins-few hrs
theory: gate control theory
low-frequency (acupuncture) TENS:
frequency:
duration:
intensity:
duty:
time:
theory:
frequency: <20 pps
duration: 100-600 microseconds
intensity: elicit sensory and motor
duty: 30s-60s on
time: 15-60 mins
theory: descending pain control theory
noxious level TENS:
frequency:
duration:
duty:
time:
theory:
frequency: 1-5 pps
duration: 100-1000 microsec
duty: 30-45 sec off
time: until pain no longer perceived
theory: endogenous opiate pain control
brief intense TENS:
frequency:
duration:
intensity:
time:
theory:
frequency: 100 pps
duration: 100-600 microsec
intensity: sustained muscle contraction
time: ~15 mins
theory: peripheral & central analgesia
which e stim is used during wound debridement?
brief intense TENS
main uses for IFC
pain control
reduce mm spasms
which type of e stim uses 4 pads in a diagonal pattern that produces sine waves at different frequencies?
IFC
what are some ways/settings that can be used to vary e stim in order to prevent the body from habituating to IFC?
target mode
sweep
scan
contraindications for e stim
pacemaker or auto defibrillator
thrombosis or occlusive vascular disease
confused and/or disoriented
internal stimulator
seizure disorder
infection
open wounds
malignancies
pregnancy
MSK Issue where contraction worsens it
high level SC injury
where should electrode NOT be placed?
chest or near heart
over carotid sinus (C3/C4)
over open wound, scars, skin lesions, areas receiving radiation therapy, protruding metal implants
electrons are ____ charged
negatively
what is an ampere?
indicates the rate
what is the current?
net movement of electrons from higher potential to lower potential
what is the electromotive force called?
volt
what is conductance?
the ease at which current flows along a conducting medium
what resists current flow?
insulators
what is ohm’s law?
the current in a circuit is directly proportional to the voltage and inversely proportional to the resistance
(current flow = voltage/resistance)
resistance to current flow (amp) is also known as
ohm
resistance of electrical flow depends on
the characteristics of the conductor
as the frequency goes up, skin impedance does _____
down
what are the 3 types of current?
biphasic = AC
monophasic = DC
pulsatile = PC (ex: EKG)
electrons always moves from _____ to ___
negative to positive
chemical reactions are balanced when currents are
balanced
what type of e stim is AC?
biphasic, TENS, IFC
which type of current may be uncomfortable?
DC
which type of e stim is DC?
iontophorsis
note: monophasic
which type of current causes an accumulation of chemicals?
DC (iontophoresis)
which type of e stim has a pulsed current?
hi volt
Russian
*most nerve/muscle stimulating currents
what is the accommodation phenomenon?
a fiber has been subjected to a constant level of depolarization will become unexcitable at that same intensity (amplitude)
T/F: current usually flows from electrode to electrode.
F
flows thru nerves and muscle = path of least resistance
the higher the ____ the longer before a response
capacitance
capacitance in a tissue can be reduced by increased ______
stimulation frequency
an increase in the diameter of the nerve ____ the capacitance
decreased
increased intensity is need to stimulate nerve with _____ capacitance
higher
pulse applies to _____ current and cycle refers to a ____ current
pulse - monophasic (DC)
cycle - biphasic (AC)
amplitude is synonymous with
voltage and intensity
how can total current increase
increasing pulse duration or pulse frequency
what determines the amount of chemical formed with DC?
pulse charge
which current always has a pulse charge >0?
monophasic (DC)
which current has no pulse charge and is the sum of phase charges?
biphasic
symmetric wave has a pulse charge of?
asymmetric?
symmetric - 0
asymmetric >0 (monophasic)
which is more comfortable for the patient? a fast or slow pulse rise
slow
doesn’t decrease skin impedance
needs more voltage for same flow
which duty ratio causes the most muscle fatigue? least?
most = 1:1
least/none: 1:7
(1:5 intermediate)
what is pulse duration?
length of time current is flowing in 1 cycle
____ determines which tissues are stimulated
phase duration
what is frequency?
the number of impulses or cycles produced by electrical stimulating device in 1 sec
skin impedance ___ as the inter-electrode distance increases
increases
skin impedance ____ as frequency decreases
increases
_____ intensity reaches to deeper tissues
higher
what is the negative electrode called?
cathode (distal)
what is the positive electrode called?
anode (proximal)
which electrode must be active to cause muscle contraction?
negative (cathode)
chemical effects are caused by which e stim type under what electrode?
hi-volt
cathode
how far apart should electrodes be placed?
1.5 times the electrode’s width
which has a greater current density? active or dispersed (esp for DC)
active
anode has a ____ effect
cathode has a ____ effect
acidic/basic
anode - acidic
cathode - alkaline/basic
current carries a ___ charge
negative
____ moves in during depolarization
____ moves out during repolarization
NA+
K+
what is the rest charge of the cell membrane?
-70 to -90
what is the strengthe-duration curvre?
threshold for depolarization of a particular nerve fiber
what is rheobase?
the intensity of a current necessary to cause observable tissue RESPONSE
what is chronaxie?
duration requires for a current of twice the intensity of rhoebase to produce tissue ECITATION
which nerves depolarize first?
large and more superficial
T/F: e stim causes stimulation of fibroblasts and osteoblasts
T
which nerve fiber are activated for noxious response?
AD and C
electrically induced contraction recruits type ___ fibers first
2
T/F: GTOs can inhibit with electrically induced muscle contraction
F
____ polarity hi volt is used for wound inflammatory phase
negative
____ polarity hi volt is used for would proliferative phase
positive
uses for Russian current
muscle strengthening
muscle re-ed
is russian AC or DC?
AC
electrode pattern difference between tens and IFC?
IFC crossed
TENS up & down patterns
electrode pattern difference between premod and IFC?
premod - 2 pads
IFC 4 pads
for IFC, which mode alters frequency? amplitude?
frequency - sweep
amplitude - scan
which IFC pattern is good for poorly localized pain?
scan
what is the pulse rate and duration for NMES or FES?
pulse rate: 35-55 pps
duration: 200-600 microsec
how should electrodes be oriented?
parallel to muscle fibers
what is the on and off settings for HVPC, med. freq. for retardation of atrophy?
on: 6-15 sec
off: 1 min
