5. Interferential Current Therapy
Interferential current (IFC) therapy is not a new technology; rather, it has been available for many years and predates all but the transcutaneous electrical nerve stimulation (TENS) unit from a longevity standpoint. When it comes to reducing tight muscles stemming from muscle guarding, muscle spasms, myofascial pain syndrome, fibromyalgia, fascial restrictions, and trigger points, my clinical nod goes to IFC first (Table 1). It has earned the right to be chosen frontline through its long and uncomplicated history of providing reliable pain reduction through reduction of muscular tension levels.
IFC is comfortable and well tolerated when patients are selected properly. Patients with a low pain/pressure tolerance do not do very well with IFC. Therefore, fibromyalgia patients need to be individually screened for this treatment. IFC involves applying 2 medium-frequency currents in a diagonal pattern criss-crossing at the intersection site or target area.
Strength of Treatment
IFC treatment uses patient-specific feedback and is controlled with an intensity dial by the provider. Like most forms of electrostimulation, it suffers from “accommodation,” whereby the provider often needs to increase the intensity to counteract the physiological tolerance that develops during a treatment session. Any time the brain can figure out the stimulation pattern, accommodation is likely to follow and be a consideration in treatment effectiveness.
Ease of Treatment
An IFC treatment setup is not intuitive because of the diagonal pattern required for this treatment mode. Despite providers being taught/trained in the correct way to set up an IFC placement, it is often performed incorrectly. There is no standardization in electrode color (red/black) from one company to the next, which creates confusion. For example, some companies have 2 of the same colors for a given channel while others have different colors for the same channel. Something as simple as electrode color can cause provider confusion and lead to incorrect electrode placement. This can potentially render the overall treatment less effective, with possible adverse effects. Also, more clarity regarding spinal electrode pad placement would be useful to improve safety and help prevent adverse effects. So it’s comforting to have an old standby such as IFC in this top 10 list, but even classic technology should continue to get even better.
Well-selected patients enjoy their IFC sessions as well as any treatment. With well-placed electrode pads, the session can be very soothing as the currents penetrate deep into muscle/fascial tissue and massage away end plate hyperactivity. Few modalities can rival the stress-reducing effects of IFC and since the electrode pads can be spaced quite far apart, the treatment area coverage can be vast providing more cost-effectiveness.
The affordability of an IFC unit is an advantage, and, as a result, it provides good value for the provider. A good case can be made for IFC for adjunctive electrotherapy as part of the care plan for many soft-tissue conditions involving pain and muscle tightness. It has limitations, however, including a limited capacity to treat a small area, such as a hand or wrist or ankle. IFC is more suited for larger treatment sites, such as the spine.
This form of electrotherapy has not been extensively studied. When application of a treatment feels this comforting, perhaps it doesn’t lend itself to a randomized clinical trial. After all, it has been used long enough to know that it feels really good and it doesn’t appear to cause any harm; borrowing electrotherapy research findings from other more studied waveforms and combining these with accepted principles of biology and physics provides a research by proxy validation of IFC. The superior properties of IFC have not been validated by research, however, there is no denying that IFC continues to be one of the most used forms of electrotherapy every day.