Modalities: TENS and IFC

Question 1

what is TENS
TENS application can be used to elicit what two things

Answer 1

the use of electrical stimulation for pain control (transcutaneous electrical nerve stimulation)
sensory analgesia or endogenous opiate liberation

Question 2

what is sensory analgesia
explain how sensory analgesia occurs

Answer 2

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

Question 3

describe conventional TENS (duration, frequency, intensity, location, response, session length, modulate)

Answer 3

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

Question 4

T or F: conventional tense elicits a muscular contraction
how does accommodation to conventional TENS occur

Answer 4

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

Question 5

how does TENS affect endogenous opiate liberation
what are the two endogenous opiates

Answer 5

produces and releases strong pain relieving substances within the body
endorphins and enkephalins

Question 6

what are the treatment goals for use of TENS with patients with chronic pain

Answer 6

functional ability while keeping pain symptoms at a manageable level

Question 7

describe acupuncture-like TENS (duration, frequency, intensity, location, response, session length, modulate)

Answer 7

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

Question 8

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

Answer 8

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

Question 9

describe conventional, low frequency, burst mode, and brief intensity TENS settings

Answer 9

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)

Question 10

what is IFC
how do the electrical currents in IFC vary in relation to one another

Answer 10

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)

Question 11

what is considered low frequency for TENS
what is considered medium frequency for IFC
how are these frequencies different

Answer 11

0-1000Hz
1000-100,000Hz
frequency for IFC is in the thousands of pulses per second, not in the hundreds

Question 12

what kind of relationship exists between the resistance of the skin and the frequency of the electrical stimulation

Answer 12

an inverse relationship, as the pulses per second increase the resistance of the skin decreases

Question 13

is IFC popular
what is IFC most commonly used for
what else can IFC be used to treat

Answer 13

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

Question 14

how is IFC produced

Answer 14

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

Question 15

IFC is based around what kind of current
what happens when the current crosses while traveling in opposite directions

Answer 15

alternating current
the resulting current will negate fully

Question 16

how can resulting current be measured
why is IFC referred to as amplitude modulated AC
what effect does IFC produce

Answer 16

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)

Question 17

what are quadripolar electrodes used to cause
what type of circuits are used in quadripolar electrodes
how should you set up the electrodes

Answer 17

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

Question 18

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

Answer 18

mean
varies at a frequency equal to the difference between these two currents

Question 19

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

Answer 19

effect
mimics low frequency currents and creates differential stimulation of nerve and tissue types
amplitude modulated frequency

Question 20

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

Answer 20

acts as carrier currents that bring the low frequency beat frequency into the tissues
chronic pain, acupuncture like TENS
acute pain, conventional TENS

Question 21

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

Answer 21

T (means you cant stimulate different motor vs A beta fibres as easily based around beat frequency)
T

Question 22

is the medium frequency or beat frequency component of TENS the dominant stimulating parameter
why does beat frequency matter

Answer 22

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)

Question 23

what is frequency sweep
what does frequency sweep reduce and allow for

Answer 23

adjusting the beat frequency
reduces accommodation, allows stimulation of a greater range of excitable tissues

Question 24

what is vector scan
what does vector scan result in
what is frequency sweep and vector scan used for

Answer 24

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

Question 25

can you place IFC over spinal nerve roots
IFC stimulates which type of sensory nerves

Answer 25

yes, when placed over nerve roots there is better improvement in functional disability than when applied to the painful area
larger diameter

Question 26

T or F: IFC is effective for pain relief through suppressing stimulation of A delta and C fibres
T or F: IFC is effective for reducing swelling

Answer 26

F, this occurs from acupuncture like TENS
F, when combined with exercises it is effective but TENS alone doesn’t reduce swelling

Question 27

does the use of cupping assist in decreasing swelling
does cupping with IFC cause action of the ANS to alter circulation

Answer 27

support for this is minimal but may be more effective when used with IFC
there is no consistent support for this

Question 28

how long should IFC treatment last for
what causes a higher risk of burn with IFC treatment

Answer 28

10-20 mins
if the effect size of the electrode is reduced by poor contact with the skin

Question 29

T or F: IFC follows the very clear frequency dependent effects displayed by TENS
what does the answer to the above suggest

Answer 29

F
that beat frequency doesn’t mimic low frequency stimulation

Question 30

does research support the use of IFC as a valid treatment choice for pain and other clinical issues
is IFC a distinctive form of treatment from TENS

Answer 30

valid for pain but not for swelling
yes, its medium frequency (not low), has alternating currents, two channels that interfere and unique properties (beat frequency)

Question 31

describe the properties of small and large electrodes
the size of the electrode correlates with what

Answer 31

small: high current density (current more concentrated), less comfortable, high resistance, superficial, more specific
large: low current density (current dispersed), more comfortable, low resistance, deeper but less specific
the area of the body you are treating (larger area = larger electrode)

Question 32

how does electrode distance affect how the current travels through the tissues

Answer 32

close together = travels superficial in tissues
far apart = travels deeper in tissues because it uses water for conduction purposes

Question 33

what are the characteristics of a good electrode

Answer 33

good conductors, non toxic, inexpensive, disposable, comfortable, sizeable

Question 34

describe the characteristics of carbon electrodes

Answer 34

time consuming application, may be displaced with movement, difficult to secure over certain body areas, non uniform pressure, can be decontaminated and used for multiple patients

Question 35

describe the characteristics of self adhesive electrodes

Answer 35

less conductive, rapid loss of conductance uniformity, unpleasant removal, may cause allergic reaction, individual patient use, expensive, more likely to cause skin irritation, loss of conductive material over time