Interferential current (IF) therapy is a more complex development of "Transcutaneous Electrical Nerve Stimulation" or TENS. While conventional TENS devices deliver electrical pulses at extremely low frequency (typically 2-150 Hz), Interferential stimulation uses medium frequencies -- above 1000 Hz, and typically around 4000 Hz. Medium frequencies travel in the tissue much more easily, can go further and deeper, and with less discomfort to the patient.

The "interference" is what occurs between the 2 or more currents used in Interferential treatment. One current has fixed frequency (typically at 4000 Hz) and the other varies by up to 400 Hz . At the point of intersection between the electrodes, which can be deeper than in TENS due to medium current's ease of penetration, the combined currents produce an "interference frequency", also called a "beat". That is a TENS-like low frequency, for example 100 Hz, and for body tissue it has a similar pain-relieving effect to TENS. Interferential also allows an increased dosage because of the better tolerance of medium-frequency currents. By using four electrodes Interferential treatment (IF) allows better focus and even deeper tissue stimulation.

Note: For more on our TENS devices, click on the "TENS Units" link under "Electrotherapy" in our left menu.