Interferential Electrical Stimulation's is a unique way of effectively delivering therapeutic frequencies to deep-seated tissue. Similar to TENS, the large impulse fibers interfere with the transmission of pain messages at the spinal cord level, aids in blood flow circulation and decreases the recovery time for patients. However, Interferential Stimulation (IF) differs from TENS because it allows a deeper penetration of the tissue with less discomfort for a given level of stimulation. In addition, conventional TENS delivers most of the stimulation directly under the electrodes whereas Interferential Stimulators will penetrate at greater depths and over a larger volume of tissue.

The most common use of Interferential Stimulation (IF) is to relieve pain, reduce swelling and edema, increased blood flow, the restoration of function associated with muscle weakness. Interferential Stimulation (IF) is used for symptomatic relief and management of chronic intractable pain and to increase localized blood flow.

Interferential therapy (IF) utilizes two medium frequency current, passed through the tissue simultaneously, where they are set up so that their paths cross and simply they interfere with each other. This interference gives rise to an interference or beat frequency which has the characteristic of a low frequency stimulation. The magnitude of the low frequency interference current is approximately equivalent to the sum of the input amplitudes. In other words, the result of the interaction between the two input currents is a low frequency current, which has an amplitude greater than either of the individual input currents. The amplitude-modulated interference wave is what makes Interferential Stimulation (IF) potentially effective and by delivering it at frequencies between 1 and 250 Hz, the stimulation will elicit a physiological response that leads to pain relief.

The basic principle of Interferential Therapy (IF) is to utilize the strong physiological effects of low frequency (@ <250pps) electrical stimulation of muscle and nerve tissues without the associated painful and somewhat unpleasant side effects of such stimulation. Because of the frequency, the interferential wave meets low impedance and will pass more easily through the skin, requiring less electrical energy input to reach the deeper tissues. This deep tissue penetration stimulates parasympathetic nerve fibers for increased blood flow and edema reduction.

Conventional TENS and Neuromuscular stimulators use discrete electrical pulses delivered at low frequencies of 2-160 Hz per second. However, Interferential stimulators use a fixed carrier frequency of 4,000 Hz per second and also a second adjustable frequency of 4,001-4,400 Hz per second.

An Interferential Stimulator may be used in these settings: pre and post orthopedic surgery; cumulative trauma disorders; back pain' arthritis' athletic and other joint injuries/syndromes; hand/wrist injuries; podiatric conditions/procedures; and pain control of various origins.