Modalities: TENS and IFC Flashcards
what is TENS
TENS application can be used to elicit what two things
the use of electrical stimulation for pain control (transcutaneous electrical nerve stimulation)
sensory analgesia or endogenous opiate liberation
what is sensory analgesia
explain how sensory analgesia occurs
stimulation of A beta nerves to cause a tingling sensation that may affect the gating mechanism at the spinal cord
stimulating touch is associated with A beta sensory and proprioception fibres so this inhibits the interneuron causing the pain signal to be inhibited from traveling to the brain
describe conventional TENS (duration, frequency, intensity, location, response, session length, modulate)
duration: short pulses
frequency: high
intensity: comfortable sensation
location: locally, along a dermatome, contralateral side of body
response: immediate
session: up to 24 hours
modulate: frequency, pulse duration, amplitude
T or F: conventional tense elicits a muscular contraction
how does accommodation to conventional TENS occur
F, since there is lower duration (short pulses) you stimulate sensation but not a muscular contraction
from a decrease in the frequency of APs along A beta fibres due to decreased excitability of nerve membrane to repeated stimulation
how does TENS affect endogenous opiate liberation
what are the two endogenous opiates
produces and releases strong pain relieving substances within the body
endorphins and enkephalins
what are the treatment goals for use of TENS with patients with chronic pain
functional ability while keeping pain symptoms at a manageable level
describe acupuncture-like TENS (duration, frequency, intensity, location, response, session length, modulate)
duration: long pulses
frequency: low
intensity: to visible muscle contraction
location: motor point where nerve innervates the muscle, acupuncture points near nerve clusters/innervation patterns, trigger points
response: 20-30 mins after, lasts 1-4 hours
session: shouldn’t exceed 30 mins
modulation: no
if you reduce the duration in conventional TENS what do you have to do with the intensity to stimulate the A beta fibres
if you decrease the duration in motor TENS how is the contraction affected
if you increase the duration in motor TENS how does this affect perception
increase the intensity
you won’t get a contraction
the window between perception of tapping and pain is small, you stimulate the A delta fibre and get pain
describe conventional, low frequency, burst mode, and brief intensity TENS settings
conventional: intensity varies so no accommodation, short duration so no motor contraction
low frequency: breaks in pulses, pulses have a greater duration, increased intensity to get muscle contraction
burst mode: pulses grouped together so you get a muscle contraction
brief intensity: constant pulses back to back with high intensity (is uncomfortable)
what is IFC
how do the electrical currents in IFC vary in relation to one another
the transcutaneous application of two separate medium frequency alternating currents
amplitude or frequency, or both (when the two currents cross they are slightly out of sync)
what is considered low frequency for TENS
what is considered medium frequency for IFC
how are these frequencies different
0-1000Hz
1000-100,000Hz
frequency for IFC is in the thousands of pulses per second, not in the hundreds
what kind of relationship exists between the resistance of the skin and the frequency of the electrical stimulation
an inverse relationship, as the pulses per second increase the resistance of the skin decreases
is IFC popular
what is IFC most commonly used for
what else can IFC be used to treat
is one of the most popular and commonly used form of electrotherapy in Canada, Europe and Australia
most commonly used for pain
swelling, accelerate tissue healing, increase BF, promote muscle strengthening
how is IFC produced
you mix two slightly out of phase medium frequency currents, one current is normally fixed frequency and the other may be adjustable
when the two asynchronous sinusoidal currents are directed to intersect the waves are periodically in synch or in phase with each other and the amplitudes of the two currents will sum together
IFC is based around what kind of current
what happens when the current crosses while traveling in opposite directions
alternating current
the resulting current will negate fully
how can resulting current be measured
why is IFC referred to as amplitude modulated AC
what effect does IFC produce
in a greater sinusoidal pattern by how often they come together and apart (full summation to negation)
because of the modulation of amplitude as the currents go in and out of synch
the interference effect (reason behind IFC name)
what are quadripolar electrodes used to cause
what type of circuits are used in quadripolar electrodes
how should you set up the electrodes
causes current produced by two circuits to interact
two bipolar circuits
in a cross over orientation so the currents cross at the point of pain
in quadripolar electrodes, the resulting current has a frequency equal to the ___ of the two original currents
in quadripolar electrodes, how does the beat frequency vary
mean
varies at a frequency equal to the difference between these two currents
beat frequency is the ___ component of IFC
what does beat frequency mimic/create
if amplitude is the factor variable in the two currents, what is beat frequency also called
effect
mimics low frequency currents and creates differential stimulation of nerve and tissue types
amplitude modulated frequency
what does the medium frequency component in IFC do
what are lower beat frequencies used for and what type of TENS is used
what are higher beat frequencies used for and what type of TENS is used
acts as carrier currents that bring the low frequency beat frequency into the tissues
chronic pain, acupuncture like TENS
acute pain, conventional TENS
T or F: alteration of beat frequencies has little effect on the threshold activation of sensory, motor and pain responses
T or F: the omission of beat frequency displays similar effects to when beat frequency is used
T (means you cant stimulate different motor vs A beta fibres as easily based around beat frequency)
T
is the medium frequency or beat frequency component of TENS the dominant stimulating parameter
why does beat frequency matter
the medium frequency component
because the body can distinguish between high and low BF settings and lower ones are more uncomfortable than higher ones (patient comfort matters)
what is frequency sweep
what does frequency sweep reduce and allow for
adjusting the beat frequency
reduces accommodation, allows stimulation of a greater range of excitable tissues
what is vector scan
what does vector scan result in
what is frequency sweep and vector scan used for
the modulation of the amplitude of one or both of the input currents
a rhythmic change in position of the interference pattern (oscillating clover leaf shape)
to offset accommodation
