Interferential Current (IFC)
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Transcript Interferential Current (IFC)
Interferential Current (IFC)
A unique use of kilohertz AC waveform
“endogenous production of the IFC”
Emphasis on use for pain control & some
limited NMES applications
Anecdotal support - tissue healing &
increase circulation via autonomic
stimulation
Hx - Dr. Hans Nemec 1950s in Austria;
popularized in US in late 70s / early 80s;
remains popular
IFC Waveform Precursors
2 electrical circuits (channels) of AC
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Medium Frequency AC (1,000 - 10,000 Hz)
One Carrier (fixed) frequency AC
One Variable frequency AC
Example: 5000 Hz / 5100 Hz. Diff = Beat Freq
Why Medium Frequency AC?
Comfortable
– With AC, higher freq = short phase
width = lower impedance
Possibility of neural block
Production of IFC
(theoretical, endogenous current)
Interference of 2 MFACs within the tissues results in
the endogenous IFC
Beat Frequency: Variable freq – Carrier freq = Beat
Waveform interaction (on an oscilloscope);
Benefit: IFC can be 2X amp of MFACs but doesn’t
have to penetrate skin
IFC production - in a
uniform medium (think 3-D)
Clover-leaf Pattern of IFC
Each circuit equal amplitude at a 90
degree angle to each other.
Vector addition
Parameters to be used
Beat Frequency & Amplitude.
Options with Beat Freq:
– Fixed vs Scanning Freq. (WHY?)
Vectoring / Sweeping of IFC
“oscillation of the cloverleaf”
– Purpose
– Physics
IFC in the Tissues: Reality ??
Clover-Leaf pattern not realistic in human tissue
Valid theoretical concept in uniform medium
IFC technology is complex, but the mechanisms
of pain control are largely the same as TENS.
Potentially better pain control
– increased depth of current
– comfort with stimulation
– typically a clinical Rx only (PT applied & supervised,
combined w/ heat or cold).
Application & Rx Guidelines
Treatment of an area of pain (joint OR soft tissue)
with IFC. Quadpolar setup, X marks the spot.
– Acute Pain: High Freq (>50), Sensory to Low Motor Amp
– Chronic Pain: Low Freq (<10), Motor to Noxious Amp
Premodulated IFC (Bipolar)
– IFC produced in the unit & delivered thru 1 channel, not
as comfortable but can put on & over; convenient
IFC – sample applications
Ant knee: IFC (left) vs Tens (right)
Gastroc: IFC (right) vs Tens (left)
Hamstring: IFC (right) vs Tens (left)
Lateral Elbow: IFC (left) vs Tens (right)