Electrotherapeutics Flashcards
uses of electrical stimulation
pain control
muscle reeducation/facilitation
reduce edema / spasticity
wound healing
testing/evaluation
big dawgs of electrotherapy
PG - Scribonius Largus
SG - Luigi Galvani
SF - Alessandro Volta
PF - Guillame B. Duchenne
C - L. Erb
6MOTY - Polio Epidemic
general ways electrotherapeutics controls pain
gate control theory
breaking of pain-spasm cycle
introduce medication to body
types of current
direct
indirect current
constant unidirectional flow current
never crosses isoelectric
how does e-stim help edema
changing electrical gradient can change the cells that are attracted and repelled
how does e-stim reduce spasticity
applied to agonist - direct muscle fatigue
applied to antagonist - reciprocal inhibition of muscle experiencing spasticity
types of current
direct
alternating
direct current is described as
constant unidirectional flow
what is direct current used for
inducing chemical reactions
how is direct current related to isoelectric line
either above or below isoelectric line
never crosses isoelectric line
alternating current is described as
change in direction of flow periodically
what is alternating current also known as
biphasic
bidirectional
how does alternating current occur
electrodes change polarity in an alternating fashion
describe alternating current in relation to isoelectric line
crosses above and below isoelectric line
pulsatile current is described as
flow of charged particles that periodically cease before the next electrical event
time related to pulsatile current
cease of current that is <1 second
explain the forms of current found in pulsatile current
can be either AC or DC
–> as long as there is some sort of pause, it turns into pulsatile current
pulsatile current and chemical effect? why?
negligible chemical effect
a sustained current changes electrochemical gradient
what is the most common clinical use of electrical current
pulsatile current
what are the types of waveforms
monophasic
biphasic
polyphasic
types of biphasic waveforms
symmetrical
asymmetrical
types of asymmetric biphasic waveforms
balanced
unbalanced
explain monophasic waveforms
all waves are on one side of isoelectric line
one pulse at a time
explain biphasic waveforms
waves cross isoelectric line
one pulse above / one pulse below
explain polyphasic waveforms
groupings of biphasic waves
symmetrical vs asymmetrical waveforms are described as
equal intensity, duration, frequency waveforms
or
opposite of that
can be either AC or DC
explain the difference between balanced and unbalanced waveforms
balanced = same amount of surface area beneath the wave
unbalanced = different amount of surface area under the wave
what are the aspects of waveforms that can be modulated
peak amplitude
pulse frequency
phase duration
indication of symmetrical biphasic waves
nerves with minimal electric charge
indication of asymmetrical biphasic waves
activation of small muscles
indication of monophasic waves
wound healing
compare fatigue between polyphasic vs monophasic/biphasic waveforms
poly = more fatiguing
mono/bi = less fatiguing
poly = longer sustained contraction
mono/bi = more rest time
how to calculate duty cycle
on time / (on + off time)
what has a direct effect on muscle fatigue
duty cycle
frequency is defined as
number of pulses delivered in one second
how is frequency of AC measured
Hz (cycles per second)
explain the levels of frequency and # of Hz associated with each
low = 1-1000 Hz
medium = 1000-10k Hz
high = >10k Hz
what has a direct effect of muscle response quality
frequency
explain how intensity is calculated
I = V/R
I = current intensity
V = voltage
R = resistance
explain how voltage and resistance effect the intensity of current
> Voltage = >I
Resistance = <I
what is resistance measured in
Ohms
insulators
- level of resistance
- examples
high
glass, rubber, paraffin, distilled H20
conductors
- level of resistance
- examples
low
copper, silver, tap water
in series, what are good insulators
skin and fat
in parallel, what are good conductors
muscle and nerve
what current is resistance related to
direct current
what current is impedance related to
alternating current
impedance is defined as
hindrance to current flow in alternating current
relationship between tissue water content and impedance
higher water content = least impedance
explain the relationship between frequency and impedance
> frequency = < impedance
define excitation
generation of an action potential
define conduction
transmission/propagation of AP away from site of stuimulation
value associated with cellular resting potential
-60 to -90 mV
explain what an absolute refractory period is
if stimulus is applied during refractory period, it will not be able to overcome and begin repolarization
explain what a relative refractory period is
if a stimulus is applied during refractory period, at a certain level of external stimulus, repolarization can begin
explain the difference between orthodromic and antidromic conduction
ortho = from spinal cord out to peripheral motor units
anti = goes from peripheral sites to spinal cord
what does effectiveness of electrical stimulation depend on
intensity (amplitude)
duration
rise time
rise time is defined as
amount of time it takes to get from isoelectric line to max intensity
what should the intensity be strong enough to do
create an action potential
explain temperature of tissue and effectiveness of e-stim
colder = slowed nerve conduction velocity, may decrease efficiency
warmer = increased nerve conduction velocity, may increase efficiency
muscle response is described as
force rather than strength
PPS necessary for _________ contraction
- twitch
- summation
- tetanus
twitch = 1-5
summation = 10-20
tetanus = 25-50
define decay time
amount of time it takes to go from peak intensity to isoelectric line
how are intensity and duration related
inversely
how is the strength duration curve calculated
plotting stimulus amplitude required to produce a minimally visible contraction as stimulus duration is varied
rheobase is defined as
minimal intensity necessary to create a contraction if the duration is considered endless
chronaxie is
intensity necessary to create two times rheobase
what is the strength duration curve used for
compare muscle groups bilaterally
compare agonist/antagonist strength
chronaxie response of _____ in msec
innervated muscle
denervated muscle
innervated muscle = 0.03
denervated muscle = 10
levels of stimulation
subsensory
sensory
motor
noxious/pain
define subsensory stimulation
no nerve fiber activation
no sensory awareness
define sensory stimulation
nonpainful paresthesia
stimulation of A-beta nerve fibers
define motor stimulation
strong paresthesia
muscle contraction
a-alpha nerve fiber activation
define noxious stimulation
strong, uncomfortable paresthesia
maxed out muscle contraction
A-delta and C-fiber activation
types of electrodes
metal plate
carbon impregnated rubber
self-adhering
what must be used for metal plate electrodes
sponge or item soaked in water
what must be used for carbon impregnated electrodes
electrode is to be wet and there must be a protective barrier
how to complete circuitry in e-stim
must have 2 leads with at least 2 electrodes secured to the body
electrode placement options
monopolar
bipolar
quadripolar
explain monopolar electrode indication/placement
for more specific treatment areas
smaller electrode is placed in treatment area and larger one is placed on same limb/side of body slightly away from the treatment area
explain bipolar set up? how to modulate
placed in a parallel sort of fashion
close = current in superficial tissue
far = current in deeper tissues
what makes a quadripolar electrode placement
if diagonal connections exist between the four electrodes
explain the response related to bipolar electrode placement when closer/further to each other
closer = more superficial, sensory response
further = more deep, motor response
in treatment of motor points, explain electrode placement
proximal 1/3 of a muscle
leads are defined as
intermediary between generator and electrodes
effectively provides a conductive pathway for current flow
jack vs tips
jack = point of exit from machine
tips = connected point on the electrodes
cleaning the skin will cause
impedance to decrease by 50%
contraindications of electric stimulation
demand type pacemakers
around/distal to thrombotic/embolic sites
pregnancy (in low back/abdominal area)
cancer
active TB
active hemorrhage
over carotid sinus
through the chest
implanted nerve stimulators
precautions of electrical stimulation
hyper/hypotension
PVD
decreased/absent sensation
history of seizures
obesity
osteoporosis
post MI - on anterior/lateral thoracic wall
metal device in pathway of current
documentation of electrotherapeutics
patient position
electrode placement
type of e-stim
duration
treatment effects
skin integrity before/after
