Lec 20 - Modalities 4 Flashcards
what does TENS stand for?
TENS = transcutaneous electrical nerve stimulation
TENS application can be used to elicit what 2 responses?
- sensory analgesia
- endogenous opiate liberation
what does sensory analgesia mean?
stimulation of A-beta nerves to cause a tingling sensation that may affect the gating mechanism at the spinal cord
Explain TENS use in the Gate control theory of pain:
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.
when would we use conventional TENS?
acute pain relief (very short and temporary)
what kind of duration is preferred for conventional TENS?
short pulses (50-100 us), this allows us to still use a high frequency that will stimulate sensory fibres but avoids stimulating muscle contraction
what frequency is preferred for conventional TENS?
high: 80-100pps (hz)
where can you place conventional TENS?
locally over area of pain, across a dermatome, on the muscle on the opposite side (contralateral)
how long can a person have conventional TENS on for?
up to 24hrs, as long as they do not sleep with it on.
why is modulation important for conventional TENS?
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.
what is the goal of TENS in endogenous opiate liberation? what does it release?
trigger the body to produce and release strong pain-relieving substances (opiates)
releases Endorphins and enkephalins
when would we use acupuncture-like TENS?
for the treatment of chronic pain to stimulate the release of pain relieving substances
what duration do we prefer for acupuncture like tens?
Long pulses (150-200 µs)
what frequency do we prefer for acupuncture-like tens?
Low (2-10 pps)
describe the differences of intensity between conventional and acupuncture like TENS:
for conventional the goal is a comfortable buzzing/tingling sensation whereas the goal of acupuncture like it muscle contraction/tapping.
a session of Acupuncture-like TENS should not exceed:
30 minutes
what is IFC?
Interferential current - The transcutaneous application of two
separate medium-frequency alternating
currents that vary in amplitude, frequency or both.
Which modalities, TENS or IFC has a higher average frequency?
IFC (ranges from 1000-100,000 Hz whereas TENS is 0-1000Hz
why is the “medium” frequency important for IFC?
skin resistance is inversely proportional to frequency, therefore at higher frequencies the skin is less resistant allowing electric stim to penetrate deeper tissues.
aside from pain, IFC has also been used to: (4)
treat swelling,
accelerate tissue healing,
increase blood flow,
and promote muscle strengthening.
IFC is sometimes referred to as what? (due to its modulation of amplitude)
amplitude modulated AC
T or F: IFC requires a bipolar electrode placement.
False, it requires a quadripolar electrode placement
in IFC the resulting current will have a _______ equal to the ______ of the 2 original currents.
frequency, mean
the “beat frequency” of IFC will vary at the frequency equal to the ______ between these 2 currents
difference
Lower beat frequencies are used for
chronic pain (like APL TENS) creates muscle tap
- What was the theory behind beat frequency? 2. Was there proven to be an important benefit?
- It was traditionally considered to mimic low-frequency currents and create differential stimulation of nerve and tissue types
- 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)
higher beat frequencies are used for
conventional acute pain (creates buzzing/tingling)
what is a frequency sweep in IFC?
allow machine to “sweep” between 2 prefixed beat frequencies which reduces accommodation
why is a vector scan helpful?
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)
T or F: both frequency sweep and vector scan are helpful to offset accommodation in IFC
true
what should the treatment time be for IFC?
10 - 20 minutes
what is the difference when electrodes are close together vs. far apart?
close together - reach superficial tissues, farther apart - will travel deeper into the tissue
what are 6 characteristics of a good electrode?
Good conductors
Non toxic
Inexpensive
Disposable
Comfortable
Sizable
what are some differences between carbon and self-adhesive electrodes?
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
