Lec 20 - Modalities 4

Question 1

what does TENS stand for?

Answer 1

TENS = transcutaneous electrical nerve stimulation

Question 2

TENS application can be used to elicit what 2 responses?

Answer 2

1. sensory analgesia
2. endogenous opiate liberation

Question 3

what does sensory analgesia mean?

Answer 3

stimulation of A-beta nerves to cause a tingling sensation that may affect the gating mechanism at the spinal cord

Question 4

Explain TENS use in the Gate control theory of pain:

Answer 4

pain is transmitted along small myelinated A-delta fibres and small unmyelinated C fibers… By using electrical stimulation we can stimulate large diameter, myelinated A beta fibres which can stimulate the SG and create an inhibitory response so pain impulses are not transmitted to the higher centres.

Question 5

when would we use conventional TENS?

Answer 5

acute pain relief (very short and temporary)

Question 6

what kind of duration is preferred for conventional TENS?

Answer 6

short pulses (50-100 us), this allows us to still use a high frequency that will stimulate sensory fibres but avoids stimulating muscle contraction

Question 7

what frequency is preferred for conventional TENS?

Answer 7

high: 80-100pps (hz)

Question 8

where can you place conventional TENS?

Answer 8

locally over area of pain, across a dermatome, on the muscle on the opposite side (contralateral)

Question 9

how long can a person have conventional TENS on for?

Answer 9

up to 24hrs, as long as they do not sleep with it on.

Question 10

why is modulation important for conventional TENS?

Answer 10

overtime a nerve fibre may begin to accommodate resulting in a decrease in the frequency of AP due to decreased excitability of the nerve membrane.

Question 11

what is the goal of TENS in endogenous opiate liberation? what does it release?

Answer 11

trigger the body to produce and release strong pain-relieving substances (opiates)
releases Endorphins and enkephalins

Question 12

when would we use acupuncture-like TENS?

Answer 12

for the treatment of chronic pain to stimulate the release of pain relieving substances

Question 13

what duration do we prefer for acupuncture like tens?

Answer 13

Long pulses (150-200 µs)

Question 14

what frequency do we prefer for acupuncture-like tens?

Answer 14

Low (2-10 pps)

Question 15

describe the differences of intensity between conventional and acupuncture like TENS:

Answer 15

for conventional the goal is a comfortable buzzing/tingling sensation whereas the goal of acupuncture like it muscle contraction/tapping.

Question 16

a session of Acupuncture-like TENS should not exceed:

Answer 16

30 minutes

Question 17

what is IFC?

Answer 17

Interferential current - The transcutaneous application of two
separate medium-frequency alternating
currents that vary in amplitude, frequency or both.

Question 18

Which modalities, TENS or IFC has a higher average frequency?

Answer 18

IFC (ranges from 1000-100,000 Hz whereas TENS is 0-1000Hz

Question 19

why is the “medium” frequency important for IFC?

Answer 19

skin resistance is inversely proportional to frequency, therefore at higher frequencies the skin is less resistant allowing electric stim to penetrate deeper tissues.

Question 20

aside from pain, IFC has also been used to: (4)

Answer 20

treat swelling,
accelerate tissue healing,
increase blood flow,
and promote muscle strengthening.

Question 21

IFC is sometimes referred to as what? (due to its modulation of amplitude)

Answer 21

amplitude modulated AC

Question 22

T or F: IFC requires a bipolar electrode placement.

Answer 22

False, it requires a quadripolar electrode placement

Question 23

in IFC the resulting current will have a _______ equal to the ______ of the 2 original currents.

Answer 23

frequency, mean

Question 24

the “beat frequency” of IFC will vary at the frequency equal to the ______ between these 2 currents

Answer 24

difference

Question 25

Lower beat frequencies are used for

Answer 25

chronic pain (like APL TENS) creates muscle tap

Question 26

1. What was the theory behind beat frequency? 2. Was there proven to be an important benefit?

Answer 26

1. It was traditionally considered to mimic low-frequency currents and create differential stimulation of nerve and tissue types
2. Research demonstrated that alteration of beat frequencies had no effect on threshold activation and pain responses. (Therefore medium frequency component is more important than beat frequency)

Question 27

higher beat frequencies are used for

Answer 27

conventional acute pain (creates buzzing/tingling)

Question 28

what is a frequency sweep in IFC?

Answer 28

allow machine to “sweep” between 2 prefixed beat frequencies which reduces accommodation

Question 29

why is a vector scan helpful?

Answer 29

when IFC is farther back,can be hard to reach a specific target tissue (bigger area covered) therefore a vector scan changes amplitudes of the 2 currents to allow the interface of the 2 current move over the area (oscillating clover leaf shape)

Question 30

T or F: both frequency sweep and vector scan are helpful to offset accommodation in IFC

Answer 30

true

Question 31

what should the treatment time be for IFC?

Answer 31

10 - 20 minutes

Question 32

what is the difference when electrodes are close together vs. far apart?

Answer 32

close together - reach superficial tissues, farther apart - will travel deeper into the tissue

Question 33

what are 6 characteristics of a good electrode?

Answer 33

Good conductors
Non toxic
Inexpensive
Disposable
Comfortable
Sizable

Question 34

what are some differences between carbon and self-adhesive electrodes?

Answer 34

Carbon
1. Time consuming application
2. May be displaced with movement
3. Difficult to secure over shoulders, hips
4. Non uniform pressure
5. Can be decontaminated
Self Adhesive
1. Less conductive
2. Rapid loss of conductance
3. uniformity
4. Unpleasant removal
5. Allergies?
6. Individual patient use
7. Relatively expensive
8. More likely skin irritation