Interferential Current

Machine Settings

1. Beat Frequency: The difference between the two medium-frequency currents (measured in Hertz/Hz)

• Lower frequency between 2-10 Hz will induce the release of endorphins to help reduce pain

• Higher frequency between 100-150 Hz will induce the blocking of pain signals to help reduce pain

• One setting for pain reduction is not inherently "better" than the other - may require several trials with a patient and gathering their feedback to find what setting works best for managing their symptoms

• Think of this as the rhythm/tempo in music

2. Intensity (amplitude): The strength of the electrical currents being delivered into the treatment area (which combine to form the therapeutic current  (measured in milliamps/mA)

• Controls how much of the current goes into the body 

• Is the only setting adjusted based on patient feedback

• Should be slowly increased until the patient feels a strong but comfortable tingling sensation

• Think of this as the volume in music

3.  Duration: The amount of time the IFC machine is on 

• Treatment is usually between 10-15 minutes

• Acute injuries can get desired effects in 5-10 minutes

• Those with chronic pain may need to receive longer treatment time (20-30 minutes)

  • Because using IFC for long periods in the clinic isn’t always practical, it’s helpful to advocate for a home unit that insurance might cover

4.  Sweep: Controls the variation of the beat frequency over time within a set range (referred to as beat low and beat high)

• Is not a setting on every machine

• This prevents nerve accommodation by constantly changing the stimulation frequency, helping maintain treatment effectiveness and patient comfort

• If a machine has this setting and the recommended beat frequency settings mentioned above are being utilized, one would simply set the beat low to 2 Hz and the beat high to 10 Hz if you are attempting to release endorphins for pain management for example

Quiz Questions

1. How many electrodes are typically used during an IFC treatment?

A. 4

B. 2

C. 3

D. 6

2. What is the purpose of crossing two medium-frequency currents in IFC?

A. To decrease skin resistance

B. To deliver heat to the muscles

C. To create a therapeutic low-frequency current deeper in the tissues

D. To strengthen the affected muscles

3. Why is IFC preferred over applying a low-frequency current directly?

A. Low-frequency currents can cause muscle spasms

B. Medium-frequency currents pass through the skin more easily and are less painful

C. High-frequency is better for bone remodeling

D. Low-frequency causes vasodilation

4. What does a beat frequency of 2–10 Hz in IFC promote?

A. Muscle hypertrophy

B. Bone healing

C. Endorphin release for pain reduction

D. Scar remodeling

5. Which machine setting in IFC helps prevent nerve accommodation by varying the beat frequency over time?

A. Intensity

B. Volume

C. Sweep

D. Pulse width

6. Which of the following is a contraindication for using IFC?

A. Chronic pain

B. Muscle spasms

C. Joint stiffness

D. Presence of a pacemaker

7. What type of neurons are primarily stimulated by the low-frequency current in IFC therapy?

A. Motor efferent neurons

B. Sensory afferent neurons

C. Sympathetic neurons

D. Interneurons

8. What pain management theory is supported by IFC’s ability to block pain signals?

A. Gate Control Theory of Pain

B. Muscle Re-education Theory 

C. Pythagorean Theorem

D. Reflex Arc Theory

9. What is a key advantage of using IFC over other forms of electrical stimulation?

A. It’s faster to apply

B. It penetrates deeper with less discomfort

C. It works without electrodes

D. It more effectively targets bone tissue