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Interferential Therapy works by sending small electrical impulses through the skin. These impulses stimulate underlying nerves and tissue reducing pain, edema and inflammation. This, in return, reduces or eliminates the need for most pain-related drugs.

Interferential Therapy was first introduced over forty years ago. Due to the size and design of the clinical unit, Interferential Therapy has been traditionally applied in hospitals or clinics.

The “portability” and “ease of use” of BioMedical Life Systems, Inc.’s INF Plus™ changes this aspect and makes it possible to introduce Interferential Therapy to the home.

Interferential Therapy is used in the treatment of circulatory disorders, range of motion, edema and muscle spasms. Post-op patients will use the device 3 times a day for 15 minutes over a period of 14 – 30 days.

Since Interferential Therapy has been in use for many years, its effectiveness is well documented. Studies have shown that patients using Interferential Therapy after surgery develop fewer post-op complications than those relying solely on narcotics for pain relief. Interferential stimulation does not cause respiratory depression. Interferential Therapy aids in circulation, increasing the recovery time for patients. Multiple treatments at home or work will typically speed the patient’s recovery and allow earlier resumption of their normal lifestyle.

Commonly Asked Questions in Regards to Interferential Therapy

Are Interferential devices safe?
YES. Although the thought of electrical impulses being sent into the body may seem frightening at first, all you really feel is a slight vibrating sensation. Unlike many drugs, Interferential devices have no known side effects.

Who cannot use an Interferential device?
Individuals with a pacemaker or patients who are pregnant should not use an Interferential device. Consult your doctor or clinician first.

How do I use the Interferential device?
Your physician will place two sterile adhesive strips on your skin one on each side of your surgical incision and will connect these to your Interferential device which provides the pain-relieving and edema-reducing stimulation.

Is an Interferential device difficult to use?
No. An Interferential device is about the same size as a transistor radio and is about as easy to use. Your doctor or clinician will instruct you on how to use your Interferential device. You may have to make minor adjustments from time to time, but this is easily done.

Will an Interferential device work for me?
Interferential Therapy has been used extensively for managing post-surgical, post-traumatic acute pain, edema and inflammation reduction. It has been used successfully for a wide variety of procedures such as:

General Surgery

• Hernia Repair
• Gall Bladder

Neurosurgery / Orthopedic
• Low Back Surgery
• Hip/Joint Repair
• ACL Repair
• Carpal Tunnel Obstetrics / Gynecology
• Gynecological
• Laparotomy
• Cesarean Section

• Hip Replacement
• Arthrotomy
• Fractures
• Sports Injuries
• Joint Mobilization Podiatry
• Hammer Toes
• Bunionectomy
• Tarsal Tunnel

• Thoracotomy

• Nephrectomy
• Prostatectomy
• Penile Implants

How expensive are Interferential devices?
When compared with the cost of lost time for recovery after surgery and continuing expense of drug therapy, an Interferential device is a very cost-effective means of treatment.

Does my insurance policy cover the cost of renting an Interferential device?
Because Interferential Therapy is a proven method for pain, edema and inflammation reduction, most insurance carriers pay for the rental or purchase of the device.

How long will I have to use my Interferential device?
Depending upon your condition, Interferential devices can be rented for short periods of time from two weeks to several months.

How do I receive the supplies necessary to use the Interferential device?
Your Health Care Dealer will send you supplies (electrodes, lead wires and batteries) on a weekly basis. They are knowledgeable in what your needs will be.

What if my Interferential device breaks?
BioMedical Life Systems, lnc.’s Interferential device carries a limited warranty period. Contact your Health Care Dealer for further information.

How do I get an Interferential device to be used after surgery?
Before obtaining an Interferential device you must first have a prescription from your physician. Once you have a prescription your Health Care Dealer can supply you with an Interferential device from BioMedical Life Systems, Inc.

Why choose BioMedical Life Systems, lnc.’s Interferential device?
BioMedical Life Systems, Inc. has been manufacturing electro-modalities for over 20 years. We manufacture quality devices that are both user friendly and proven effective in both pain relief and in edema reduction.

Where can I get further information on Interferential?
You can talk to your physician or contact your Health Care Dealer. For more information or the name and address of your nearest BioMedical Life Systems, Inc. Health Care Dealer, call toll free (800) 726-8367.


  • Amplitude – Intensity is the output of electrotherapy distributed by the unit to the patient. Depending on the waveform, intensity is measured in milliamps (mA), volts (V), and microamps (μA).
  • Beat continuous – Associated with the Interferential waveform, Beat Continuous is the parameter at which the beat frequency remains constant. When the Sweep setting is turned off, you must select a fixed beat for the therapy session.
  • Beat High – During a sweep, the Beat High setting is the highest number to which the beat frequency increases. The available range for the Beat High parameter is 80 to 150 Hz. This parameter is unique to the Premodulated and IFC waveforms.
  • Beat Low – During a sweep, the Beat High setting is the highest number to which the beat frequency decreases. The available range for the beat low parameter is 1 to 10 Hz. This parameter is unique to the Premodulated and IFC waveforms.
  • Beat Wide – During a sweep, the Beat Wide setting is the lowest number to the highest beat frequency. The available range for the Beat Low parameter is 1 to 250 Hz. This parameter is unique to the Premodulated and IFC waveforms.
  • Burst – Burst is a series of pulses at a predetermined pulse frequency.
  • Burst Frequency (Freq.) – This is the number of bursts per second (bps). This parameter is unique to the Russian waveform.
  • Carrier Frequency (Freq.) – This is the frequency of the unmodulated medium frequency current. The available carrier frequencies are 2,500, 5,000, and 15,000 Hz for Russian, Interferential and Microcurrent respectively.
  • Channel Mode – The available channel modes are Reciprocal (where electrotherapy alternates between channels), and Co-Contract (where electrotherapy is distributed from both channels at the same time). This parameter is unique to the EMS and Russian waveform.
  • Co-Contract – Where the timing of stimulation can be coordinated through two channels to simultaneously co-contract agonist and antagonist or differing sections of a larger muscle group.
  • Compliance Timer – Logs the total treatment time that the unit has provided. The unit of logging is 10 minutes (i.e. if the instrument is used between 1-10 min. the unit will be one). (10 minutes = 1 unit).
  • Compliance Number – Log the total number of treatments taken from the instrument.
  • Cycle Time – Cycle Time is the alternating time that the current is “on” and “off.” Contraction and Relaxation time can be set from 1-99 seconds. This parameter is unique to the EMS, Russian, Premodulated, and High Volt waveforms.
    Duty Cycle – This is the ratio of the “On” time to “Total” time of the cycle, expressed as a percentage. The duty cycle describes the pulsed modes of electric stimulation (the lower the percentage, the lower temporal average intensity). 100% is continuous electrotherapy. The available duty cycles are 10, 20, 30, 40, and 50%. This parameter is unique to the Russian waveform.
  • Frequency – The number of times per second a pulse will repeat itself.
  • High Volt Pulse Current – (HVPC) has a very brief pulse duration characterized by two distinct peaks delivered at high voltage. The waveform is monophasic (current flows in one direction only). The high voltage causes a decreased skin resistance making the current comfortable and easy to tolerate.
  • Interferential Current – (IFC) is a medium frequency waveform. Current is distributed through two channels (four electrodes). The currents cross each other in the body at the area requiring treatment. The two currents interfere with each other at this crossing point, resulting in a modulation of the intensity (the current intensity increases and decreases at the beat frequency).
  • Microcurrent – (MENS) is a monophasic waveform of very low intensity that closely stimulates the electrical current generated by the human body.
  • Polarity – Refers to the charge of an individual lead: positive, negative or alternating. This parameter is unique to the High-Volt waveform and Microcurrent.
  • Premodulated Interferential Current – This is a medium frequency waveform. Current comes out of one channel (two electrodes). The current intensity is modulated: it increases and decreases at a regular frequency (the Amplitude Modulation Frequency).
  • Ramp – The gradual increase and decrease in current. The purpose of ramping up the current is to maximize patient comfort by preventing the abrupt and sudden exposure to the current. This parameter is unique to the Russian, EMS, and High-Volt.
  • Reciprocal – Application where stimulation alternates between agonists and antagonists.
  • Russian Current – This is a 2,500 Hz carrier wave, interrupted to create pulse trains or “bursts.” The number of bursts per second is determined by the burst frequency and the length of the bursts is determined by the duty cycle.
  • Sweep – This is the modulation of therapeutic frequency commonly used to prevent accommodation. Sweeps are measured in pulses per second (pps) and Hertz (Hz). This parameter is unique to the Interferential and Premodulated.
  • Vector – A vector is a geometrically descriptive feature used to increase the effective therapeutic current at the crossing point of Traditional Interferential (IFC); increases one channel’s amplitude while simultaneously decreasing (by the same percentage) the other channel’s amplitude with a single key press.
  • Vector Scan – Measured in percentages, vector scans are the rhythmic changes of the position of the vector. This parameter is unique to the Interferential.