What is interferential therapy?
Interferential therapy originated in Germany and was administered by an interferential physiotherapist originally in a physiotherapy department. In the U.S. it was about 1960 before there were interferential physical therapists using the new modality.
What does it involve?
Interferential therapy basically involved putting 4 electrodes on the outer edges of where a patient was feeling pain. The interferential current therapy consisted of one “channel -2 electrodes” going off and on 4,000 times per second ( referred to as PPS/Frequency/Rate/Pulses per Second). The other channel went off and on 4,001 to 4,150 PPS. The interferential therapy treatment was the crossing of the currents inside the patient which stopped the pain and also provided carryover pain relief following the treatment that lasted for some time period. In physical therapy journals there were interferential articles describing how the treatment worked and why interferential was most beneficial for chronic pain patients who were unable to find pain relief.
Often the chronic pain patient was referred to a Physical Therapist ( Physiotherapist ) by a physician for an “Evaluate and Treat” referral. The physicians were unaware of what the physical therapists were doing but they found that in many situations the physical therapist was able to provide pain relief when other methods had failed. The physical therapist often used a combination of hot cold interferential which was nothing more than applying warm moist heat in conjunction with interferential for immediate relief and to extend the carryover pain relief period. If the patient presented with an acute injury, less than 48 hours, then the physical therapist used cold interferential therapy employing ice to lessen the inflammation of recently injured tissues.
The reason for the warm moist heat, in conjunction with interferential treatments, was the heat attracted blood, a conductor of electricity, and enhanced the ability of the interferential current to penetrate into the body tissues and target the sensory nerves. When there is more heat in an area the body rushes blood to dissipate the heat. This creates a more electrical conductive environment internally and externally the moisture from the heating pad reduces the resistance of the skin for greater penetration. The physical therapist was using the natural phenomena to aid in overcoming the resistance of the skin.
In theory the crossing of the two currents from the two independent channels would produce a “new” current that was the sum of the two crossing currents. That was theory which later had to be modified since the body and the differing tissues had different abilities to store electrons before “filling up” and there was not a consistency of current distribution. However the science was correct even though the imagery was not. This “new current” was called a “vector current” and it moved around the painful areas. What was later revealed was the stimulation did indeed occur for the sensory nerves due to the crossing of the currents. The sensation was very relaxing and the effects of interferential currents were successful for pain relief.
Interferential therapy later moved to other medical disciplines and become an effective treatment for:
1. Urinary and Fecal Incontinency
3. Muscle Reeducation
4. Acute Edema
5. Muscle spasm and spasticity
6. Circulatory stimulation
7. Abdominal Organ stimulation
8. Acceleration of general healing.
Unfortunately during the time interferential was being used there was little research being done on the how and whys other than one book published in 1984 by Brenda Savage, physiotherapist, called “Interferential Therapy”.
In 1987 Dr. Giovanni De Domenico came out with the literal “encyclopedia of interferential current therapy” called, “New Dimensions In Interferential therapy. A Theoretical & Clinical Guide”.
Over the years study after interferential study has confirmed what Brenda Savage and Giovanni De Domenico pointed out decades earlier. Interferential therapy currents could produce outstanding clinical results for patients when other treatments had failed.
Interferential therapy contraindications are few,
1. Don’t apply electrodes near heart if patient has a demand cardiac pacemaker
2. Don’t apply electrodes over neck
3. Don’t use interferential therapy on pregnant women,
Unlike tens units, transcutaneous electrical nerve stimulators, prior to January 2009 interferential units were not portable so any contraindication of sleepiness due to muscle relaxation was not hazardous since the patient had to be in a clinic or hospital to receive an interferential treatment. It was not unusual for a patient to fall asleep during an interferential treatment and have to be awakened upon completion by the clinician.
Today with the advent of at home, self treat, with a portable device the additional warning is to not operate an automobile or operate machinery when undergoing interferential treatment. Today, besides the physical therapy interferential office, the chiropractic clinic often uses interferential therapy as a complementary therapy to spinal manipulation and the Doctor of Chiropractic has become well versed in using interferential for pain relief.
The biggest problem with interferential therapy historically has been one had to get an appointment and go to a clinic for treatment. Today that is not the case and the ability to self treat has turned the tide on preventing pain, rather than treating pain.
Probably the principal advantage to the patient is today with self treatment interferential options, the residual or carryover pain relief seems to be extending from self treatment to self treatment and new parameters of health care are emerging due to the new portable modality..
In conclusion, even though the exact mechanisms of why interferential therapy worked were not known, the benefits were solid and the use of interferential currents for pain and other health issues has prospered. Interferential currents have helped many patients in clinics and now can help outside the clinic in the home setting. New knowledge is emerging as the results of preventing pain with self treatment is changing the understanding of interferential current therapy.