Weak Signal – Big Response - part 2 - by Mac Stein, PT
Weak signal – BIG RESPONSE is a known phenomenon in biology : it is not necessary to deliver a strong signal in order to obtain a desirable physiological response. Surprisingly weak signals are capable of generating impressive beneficial responses. Stronger-than-necessary signals may actually carry a high risk for undesirable results such as over-medication toxicity or for dangerous side effects. The concept of weak signal PEMF therapy was introduced in the previous article. Readers who missed last month’s article are encouraged to find it in the December 2016 digital version of Bridle and Bit. The digital versions also contain additional color images that can also be accessed at www.msteinpt.com.
Weak signal PEMF therapy units such as HealFast include a computer chip powered by a 3 Volt button battery generating a pulsed RF signal that travels through a small loop antenna. The signal penetrates the tissues underneath the antenna by inductive coupling: no wires, no electrodes, no gel and no skin preparation. SKIN CONTACT IS NOT REQUIRED. The signal penetrates through bandages, wraps, even cast. It will not penetrate metal. As the signal travels into the tissues away from the antenna the EMF gets wider but weaker. These units are designed to treat a variety of soft tissue injuries and conditions. At 10 centimeters (3.75 inches) of penetration depth the signal is still capable of producing a physiological response as per NIH standards. In reality it is effective at even greater depths. As mentioned in Part 1, PEMF therapy is the delivery of exogenous (generated outside the body) EMFs to the injured tissue and cells in order to favorably affect the disrupted endogenous (created by and within the body) EMFs. It appears that several different configurations of weak RF signals are capable of producing beneficial results. In other words – different brands of PEMF therapy devices are capable of safely producing beneficial results even though they employ slightly different RF signals. Researchers believe that at some future point each type of injury/condition will respond optimally to a signal specific to that injury. For this to happen, all tissues have to have their endogenous EMFs mapped first. Endogenous EMFs are influenced by– if not created by - movement of charged ions inside, outside and across the cell membrane.
When a weak signal PEMF therapy device is activated either in direct contact with the skin or over a bandage, the horse (or human, or small animal) does not feel anything: No tingling, no muscle twitching and no heat. In fact, scientific reviews classify these weak RF signals as a-thermal and non- ionizing. This is one reason why these units are safe to use immediately post injury or post surgery. This is an advantage over signals such as therapeutic ultrasound or low level laser therapy (LLLT) in which application immediately post injury is cautioned against. Much stronger radio frequency signals can generate much heat in the tissue , and are used judiciously in certain surgeries or in cosmetic procedure. In order to achieve the desired localized response the loop antenna of the PEMF therapy unit has to be positioned over the injured tissue as determined by your veterinarian. The shape and size of the antenna determine the shape, size and orientation of the EMFs. There are various creative ways to secure a unit to almost any body part, and the horse can then be turned loose in the stall or paddock, loaded in the trailer or even lightly ridden depending on the specific injury or condition. The unit is left on for hours. In some cases in can be left on 24/7 with daily checking to make sure the unit is still working, and that the wrap is not interfering with circulation. Draining wounds may have to be cleaned and re-bandaged as HealFast does a very good job at draining wounds and surgical incisions, and at drawing out abscesses. In the case of musculoskeletal injuries with lameness, swelling, pain and inflammation – the often quick reduction of these symptoms should not be misinterpreted as complete healing. Particularly so with performance horses. Check with your veterinarian prior to resuming exercise. Horses and dogs with arthritic pain may need 2-3 days of PEMF therapy before improvement is noticeable. Arthritic animals and people often experience pain relief to the extent that anti-inflammatory medications can be cut back or even discontinued. Caution should be used with either free exercise or drills as it is likely that several muscle groups have by now gone weak: Dogs with hip arthritis that were reluctant to jump off the pickup bed feel good all of a sudden. They jump off and they crash, getting their feelings hurt.
Re-normalizing disturbed cell membrane potential of injured cells was believed to be the mode of action of weak signal PEMF, much like micro-current therapy does, by influencing movement of charge carrying minerals - primarily sodium and potassium - across the cell membrane. This did not explain how weak PEMF can be so effective across such a wide range of injuries and conditions. Published research over the past ¼ century has clearly demonstrated and documented additional modes of action. Through its effect on calcium binding with other molecules such as Calmodulin, weak RF signals can rapidly increase the localized production of the anti-inflammatory type of Nitric Oxide (NO), countering the effect of the inflammatory type of NO which is produced as an immediate response to injury. This good kind of NO also modulates the production of another important molecule – cGMP, which in turn modulates the production of various growth factors essential for growth and repair. Weak RF signal also arrest the production of Interleukin -1β. Simply stated – supplying a concentrate of growth factors to the injured tissue is what PRP aims to do, and curbing the effect of Interleukin-1β is what IRAP has to offer. One can safely get a jump start on these procedures while the veterinarian is processing the blood sample. Weak RF signals have also been shown to boost angiogenesis (proliferation of new capillaries), to modify gene expression, to speed up nerve regeneration and to modify some disease processes. Veterinarians, other clinicians, trainers and horse owners have a hard time assimilating this information, especially if they have not been following relevant research findings step-by-step.
In next month’s article we will review this information from a slightly different perspective, including specific injuries. Hopefully this will further clarify how this “no bells-no whistles” inexpensive therapy box tool can outperform devices that cost thousands to tens of thousands of dollars, are effective only in a limited range of injuries and conditions, and have risks associated with them.
Mac Stein is a physical therapist specializing in orthopedic sports injuries and animal physical therapy. He is also a non-pro reined cowhorse rider and competitor.
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