Interferential Current (IFC) (WEEK 10) Flashcards Preview

PTHER 555 - Therapeutic Modalities > Interferential Current (IFC) (WEEK 10) > Flashcards

Flashcards in Interferential Current (IFC) (WEEK 10) Deck (35):
1

IFC: how does it work/goal

electrical current delivered to the surface of the skin to stimulate nerves to fire (sensory, motor, nociceptors) to manage pain control

pain control**

2

IFC vs TENS: mechanism

IFC: transcutaneous application of two alternating media,-frequency electrical currents

TENS: one alternating current at a low frequency

3

IFC carrier frequency range

3000-5000Hz

4

IFC: Therapeutic Effects

main therapeutic benefit: PAIN MODULATION

pain modulation by
1. pain gate mechanism
2. DEOS
3. endogenous opioid release at the level of the spinal cord

5

IFC: other therapeutic effects

- oedema control
- muscle retraining

6

IFC vs. TENS
- frequency
- comfort
- depth

- frequency
IFC: Medium
TENS: low

- comfort
high frequency IFC is more comfortable

- depth
IFC penetrates deeper into tissue and therefore can stimulate deeper nerves

7

IFC: depth

IFC uses 2 oscillating currents and when the currents and crossed and synchronized they superimpose on one another and we get summation of their amplitudes

- current travels from one electrode to another in an arched path, the further apart the electrodes the deeper the arc.

8

IFC: currents cancel out

If two oscillating currents are a half cycle out of sync then they cancel each other out completely - 100%

9

IFC: currents slightly out of sync

When two oscillating waves are slightly out of sync (5000Hz and 5100Hz), the resulting wave pattern is a series of "BEATS"

10

IFC: Beats

currents slightly out of sync
1. Perfect summation: every few beats circuit 1 and 2 are in sync and summate

2. Perfect cancelation: every few beats circus 1 and 2 are half cycle out of sync and cancel out

3. Partial summation or cancellation: majority of the time the beats partially summate or cancel

11

Beat frequency - what is it?

- beats per second, also known as amplitude modulated frequency (AMF)

- equal to the frequency difference between the two carrier frequency of oscillating waves. For example:
- Circuit 1: carrier frequency = 5100Hz
- Circuit 2: carrier frequency = 5000Hz
when circuit 1 and 2 cross we get beat frequency (AMF) of 100Hz

12

Beat frequency - significance

Amplitude of the beats has a stronger amplitude than the original currents

- stronger beat deep in tissue

- at the location where the currents cross, we get our beat frequency which is of a stronger intensity than the carrier frequency

13

IFC pattern

clover-leaf pattern of current

14

True IFC: how does this work?

- cross-fire arrangement of 4 electrodes to create 2 separate currents
- interference of two currents occurs within the tissue
- stimulation: superficial and deeper tissue

15

Pre-modulated ICF

- 2 currents are mixed within the machine so that the frequency is delivered by a single circuit

- no crossing and summation of currents within tissue, therefore we are not creating a stronger beat deeper in the tissue
- beat frequency pattern is delivered to the surface of the skin

16

Pre-modulated ICF: stimulation location

most of the nerve stimulation occurs directly under the electrodes as we do with tens but since we are using a medium frequency then it may be more comfortable than TENS

17

True vs. Pre-modulated ICF

- no difference own clinical outcome when it comes to stimulating sensory, motor, or pain thresholds

- True: more effective at targeting deeper tissues

- pre-mod: more comfortable

18

ICF vs. TENS: Beat frequency/AMF

when setting frequency we do not consider pulse width directly, rather we are setting the beat frequency

19

Beat frequency/AMF
- sensory

- motor

- pain

- sensory: 50-80Hz

- motor: <10Hz

- pain: >120Hz

20

Intensity:
- sensory

- motor

- pain

- sensory: comfortable

- motor: less comfortable

- pain: uncomfortable/painful

21

Proposed mechanism

- sensory: pain gate

- motor: DEOS, opioid release at SC

- pain: DEOS, opioid release at SCI

22

Onset/Duration of pain relief

- sensory: fast and short

- motor: slow and long

- pain: fast and long

23

Treatment times

- sensory: 15-20 mins

- motor: at least 30 mins to stimulate opioid release

- pain: depends on pt tolerance (15-30 mins)

24

AMF: frequency - beat relationship

- high beat frequency, we get shorter beats (shorter "pulse duration")
- lower beat frequency, we get longer beats

- increase frequency, decrease pulse duration

25

AMF - strength duration curves

lower beat frequency would move us to the right of the graph (just as longer pulse duration would)

26

AMF parameter

changing AMF does not differentially stimulate different nerves and tissues
- change to pain threshold were similar with AMF settings 0-100Hz
- sensory threshold unaffected with varying AMF
- True IFC frequencies showed similar deep stimulation
- Similar + effects on pain when applying AMF frequency on Knee OA

27

AMF relevance

- behaviour in tissue is unpredictable because perhaps
- currents not crossing gat all
- no AMF is being created

28

True and pre-modulated ICF predicability

Pre-modulated: ICF highest voltage in line with one circuit

True ICF: lowest was in the middle of the 4 electrodes, highest was recorded outside (5cm) the electrodes

29

Comfort (Frequency)

- higher AMF setting (50-100Hz) more comfortable than low frequency (1-10Hz)

30

Modulation setting (sweep, modulated)

- decrease habituation/accomodation of the target nerve
- fluctuating AMF may reduce habituation of nerve due to repetitive stimuli

31

ICF and TENS: experimental pain

effective in treating various forms of experimental pain
- Mechanical pain
- Cold pain
- Heat pain
- Ischaemic pain
- Chemical pain

32

IFC: LBP

- effective for pain and disability in chronic LBP

33

IFC: OA

- reduced pain and increased function; better with exercise

- no significant additional effects over exercise alone

34

Adjunct treatment (acute/chronic LBP, frozen shoulder, knee OA)

- more effective than control at discharge
- more effect than placebo at 3 months follow up

35

IFC Alone (chronic LBP, knee OA, jaw pain)

not significantly better than placebo or therapies