|Biomed Sci Instrum. 2004;40:469-74.|
Noninvasive treatment of inflammation using electromagnetic fields: current and emergin therapeutic potential.
Johnson MT, Waite LR, Nindl G.
Center for Medical Education, Indiana University School of Medicine, Terre Haute, IN 47809, USA.
Magnets, electric current and time varying magnetic fields always have played a role in human medicine. Natural magnetic stones were used in ancient cultures to induce a therapeutic effect and modern clinical practice would be far less effective without nuclear magnetic resonance imaging, cardiac pacemakers, and bone growth stimulators. This paper presents a summary of natural and artificial electromagnetic field (EMF) characteristics that are currently in use or under investigation for other therapeutic applications. This background understanding provides a basis for discussion on the success and possible risks of emerging and novel EMF therapies. Although interest in energy medicine has existed for centuries in some parts of the world, in recent years this is an area of heightened interest for western healthcare practitioners. This awareness has been triggered by the growing body of knowledge on how EMFs interact with cellular systems. EMF therapy for the treatment of pain, cancer, epilepsy, and inflammatory diseases like psoriasis, tendinitis and rheumatoid arthritis is currently being explored. The long-term success of this new area of medicine is still unknown. On the one hand, it remains to be seen whether positive human outcomes with EMF therapy could be explained by enhancement of the placebo effect. Optimistically, EMF therapy has the potential to revolutionize medicine, which is currently dominated by pharmaceutical and surgical interventions. In this case, new therapeutic tools may be developed for future clinicians to provide noninvasive treatments with low risk of side effects and no problem with drug interactions.
Possible therapeutic applications of pulsed magnetic fields
Navratil, L. et.al. Czech Republic
Magnetotherapy is a relatively new, nowadays however, relatively widespread method in several medical disciplines. The mechanism proper of the favorable action of the pulsed magnetic field on the living organism is not quite clear so far, clinical investigations revealed, however, a favorable anti-inflammatory, angioedematous and analgesic therapeutic effect. The authors sought an optimal frequency of the pulsed magnetic field with regard to the character of the disease. They focused attention above all on treatment of acute and chronic inflammatory conditions of the locomotor apparatus, ischaemia of the blood vessels of the lower extremities, dyspeptic syndrome, lactation mastitis and other diseases. One therapeutic cycle lasted 20 minutes, the mean number of cycles varied between 5.8 and 7.7. A regression of complaints was recorded as a rule after 2-3 sessions. The optimal frequency of the pulsed magnetic field seems to be a value between 10.0 and 25.0 Hz. It is useful in particular in severe conditions to repeat the therapeutic cycle after 2-3 months. The advantage of this therapeutic method is the minimal number of contraindications.
|Kosm Biol Aviakosm Med. 1990 May-Jun;24(3):3-11.|
Effect of low-frequency electromagnetic fields on the individual functional systems of the body.
[Article in Russian]
Zagorskaia EA, Klimovitskii VIa, Mel’nichenko VP, Rodina GP, Semenov SN.
This paper is a review of recent publications about the effects of low frequency electromagnetic fields (EMF) (constant and pulsed) on the cardiovascular, neuroendocrine, and blood systems of experimental animals and industrial workers exposed to them. It is reported that the regulatory systems (nervous and endocrine) are highly sensitive to EMF. It is obvious that investigations of hormone-receptor interactions can help better understand EMF effects on the endocrine system and the body as a whole. Published data about EMF effects on the cardiovascular system and blood are often contradictory, probably, because of different estimates of allowable limits recognized in various countries. It is hypothesized that circulatory changes are largely dependent on the central regulatory structures, particularly hypothalamus. White blood responses to the exposure, being most significant among hematological reactions, are also induced, to a certain extent, by regulatory mechanisms. The EMF effects may depend on the initial state and individual properties of the biological organism. It is postulated that the EMF effects on regulatory mechanisms may be related to primary disorders in cellular and mitochondrial membranes.
Beneficial effects of electromagnetic fields.
Bassett C. Bioelectric Research Center, Columbia University New York
Selective control of cell function by applying specifically configured, weak, time-varying magnetic fields has added a new, exciting dimension to biology and medicine. Field parameters for therapeutic, pulsed electromagnetic field (PEMFs) were designed to induce voltages similar to those produced, normally, during dynamic mechanical deformation of connective tissues. As a result, a wide variety of challenging musculoskeletal disorders have been treated successfully over the past two decades. More than a quarter million patients with chronically ununited fractures have benefitted, worldwide, from this surgically non-invasive method, without risk, discomfort, or the high costs of operative repair. Many of the athermal bioresponses, at the cellular and subcellular levels, have been identified and found appropriate to correct or modify the pathologic processes for which PEMFs have been used. Not only is efficacy supported by these basic studies but by a number of double-blind trials. As understanding of mechanisms expands, specific requirements for field energetics are being defined and the range of treatable ills broadened. These include nerve regeneration, wound healing, graft behavior, diabetes, and myocardial and cerebral ischemia (heartattack and stroke), among other conditions. Preliminary data even suggest possible benefits in controlling malignancy.
Bioelectromagnetics Applications in Medicine
PANEL MEMBERS AND CONTRIBUTING AUTHORS
Beverly Rubik, Ph.D.–Chair
Robert O. Becker, M.D.
Robert G. Flower, M.S.
Carlton F. Hazlewood, Ph.D.
Abraham R. Liboff, Ph.D.
Jan Walleczek, Ph.D.
Bioelectromagnetics (BEM) is the emerging science that studies how living organisms interact with electromagnetic (EM) fields. Electrical phenomena are found in all living organisms. Moreover, electrical currents exist in the body that are capable of producing magnetic fields that extend outside the body. Consequently, they can be influenced by external magnetic and EM fields as well. Changes in the body’s natural fields may produce physical and behavioral changes. To understand how these field effects may occur, it is first useful to discuss some basic phenomena associated with EM fields.
In its simplest form, a magnetic field is a field of magnetic force extending out from a permanent magnet. Magnetic fields are produced by moving electrical currents. For example, when an electrical current flows in a wire, the movement of the electrons through the wire produces a magnetic field in the space around the wire (fig. 1). If the current is a direct current (DC), it flows in one direction and the magnetic field is steady. If the electrical current in the wire is pulsing, or fluctuating–such as in alternating current (AC), which means the current flow is switching directions–the magnetic field also fluctuates. The strength of the magnetic field depends on the amount of current flowing in the wire; the more current, the stronger the magnetic field. An EM field contains both an electrical field and a magnetic field. In the case of a fluctuating magnetic or EM field, the field is characterized by its rate, or frequency, of fluctuation (e.g., one fluctuation per second is equal to 1 hertz [Hz], the unit of frequency).
A field fluctuating in this fashion theoretically extends out in space to infinity, decreasing in strength with distance and ultimately becoming lost in the jumble of other EM and magnetic fields that fill space. Since it is fluctuating at a certain frequency, it also has a wave motion (fig. 2). The wave moves outward at the speed of light (roughly 186,000 miles per second). As a result, it has a wavelength (i.e., the distance between crests of the wave) that is inversely related to its frequency. For example, a 1-Hz frequency has a wavelength of millions of miles, whereas a 1-million-Hz, or 1-megahertz (MHz), frequency has a wavelength of several hundred feet, and a 100-MHz frequency has a wavelength of about 6 feet.
All of the known frequencies of EM waves or fields are represented in the EM spectrum, ranging from DC (zero frequency) to the highest frequencies, such as gamma and cosmic rays. The EM spectrum includes x rays, visible light, microwaves, and television and radio frequencies, among many others. Moreover, all EM fields are force fields that carry energy through space and are capable of producing an effect at a distance. These fields have characteristics of both waves and particles. Depending on what types of experiments one does to investigate light, radio waves, or any other part of the EM spectrum, one will find either waves or particles called photons.
A photon is a tiny packet of energy that has no measurable mass. The greater the energy of the photon, the greater the frequency associated with its waveform. The human eye detects only a narrow band of frequencies within the EM spectrum, that of light. One photon gives up its energy to the retina in the back of the eye, which converts it into an electrical signal in the nervous system that produces the sensation of light.
Table 1 shows the usual classification of EM fields in terms of their frequency of oscillation, ranging from DC through extremely low frequency (ELF), low frequency, radio frequency (RF), microwave and radar, infrared, visible light, ultraviolet, x rays, and gamma rays. For oscillating fields, the higher the frequency, the greater the energy.
Endogenous fields (those produced within the body) are to be distinguished from exogenous fields (those produced by sources outside the body). Exogenous EM fields can be classified as either natural, such as the earth’s geomagnetic field, or artificial (e.g., power lines, transformers, appliances, radio transmitters, and medical devices). The term electropollution refers to artificial EM fields that may be associated with health risks.
In radiation biophysics, an EM field is classified as ionizing if its energy is high enough to dislodge electrons from an atom or molecule. High-energy, high-frequency forms of EM radiation, such as gamma rays and x rays, are strongly ionizing in biological matter. For this reason, prolonged exposure to such rays is harmful. Radiation in the middle portion of the frequency and energy spectrum–such as visible, especially ultraviolet, light–is weakly ionizing (i.e., it can be ionizing or not, depending on the target molecules).
Although it has long been known that exposure to strongly ionizing EM radiation can cause extreme damage in biological tissues, only recently have epidemiological studies and other evidence implicated long-term exposure to nonionizing, exogenous EM fields, such as those emitted by power lines, in increased health hazards. These hazards may include an increased risk in children of developing leukemia (Bierbaum and Peters, 1991; Nair et al., 1989; Wilson et al., 1990a).
However, it also has been discovered that oscillating nonionizing EM fields in the ELF range can have vigorous biological effects that may be beneficial and thus nonharmful (Becker and Marino, 1982; Brighton and Pollack, 1991). This discovery is a cornerstone in the foundation of BEM research and application.
Specific changes in the field configuration and exposure pattern of low-level EM fields can produce highly specific biological responses. More intriguing, some specific frequencies have highly specific effects on tissues in the body, just as drugs have their specific effects on target tissues. The actual mechanism by which EM fields produce biological effects is under intense study. Evidence suggests that the cell membrane may be one of the primary locations where applied EM fields act on the cell. EM forces at the membrane’s outer surface could modify ligand-receptor interactions (e.g., the binding of messenger chemicals such as hormones and growth factors to specialized cell membrane molecules called receptors), which in turn would alter the state of large membrane molecules that play a role in controlling the cell’s internal processes (Tenforde and Kaune, 1987). Experiments to establish the full details of a mechanistic chain of events such as this, however, are just beginning.
Another line of study focuses on the endogenous EM fields. At the level of body tissues and organs, electrical activity is known to exhibit macroscopic patterns that contain medically useful information. For example, the diagnostic procedures of electroencephalography (EEG) and electrocardiography are based on detection of endogenous EM fields produced in the central nervous system and heart muscle, respectively. Taking the observations in these two systems a step further, current BEM research is exploring the possibility that weak EM fields associated with nerve activity in other tissues and organs might also carry information of diagnostic value. New technologies for constructing extremely sensitive EM transducers (e.g., magnetometers and electrometers) and for signal processing recently have made this line of research feasible.
Recent BEM research has uncovered a form of endogenous EM radiation in the visible region of the spectrum that is emitted by most living organisms, ranging from plant seeds to humans (Chwirot et al., 1987, Mathew and Rumar, in press, Popp et al., 1984, 1988, 1992). Some evidence indicates that this extremely low-level light, known as biophoton emission, may be important in bioregulation, membrane transport, and gene expression. It is possible that the effects (both beneficial and harmful) of exogenous fields may be mediated by alterations in endogenous fields. Thus, externally applied EM fields from medical devices may act to correct abnormalities in endogenous EM fields characteristic of disease states. Furthermore, the energy of the biophotons and processes involving their emission as well as other endogenous fields of the body may prove to be involved in energetic therapies, such as healer interactions.
At the cutting edge of BEM research lies the question of how endogenous body EM fields may change as a result of changes in consciousness. The recent formation and rapid growth of a new society, the International Society for the Study of Subtle Energies and Energy Medicine, is indicative of the growing interest in this field._
Figure 3 illustrates several types of EM fields of interest in BEM research.
Medical Applications of Bioelectromagnetics
Medical research applications of BEM began almost simultaneously with Michael Faraday’s discovery of electromagnetic induction in the late 1700s. Immediately thereafter came the famous experiments of the 18th-century physician and physicist Luigi Galvani, who showed with frog legs that there was a connection between electricity and muscle contraction. This was followed by the work of Alessandro Volta, the Italian physicist whose investigation into electricity led him to correctly interpret Galvani’s experiments with muscle, showing that the metal electrodes and not the tissue generated the current. From this early work came a plethora of devices for the diagnosis and treatment of disease, using first static electricity, then electrical currents, and, later, frequencies from different regions of the EM spectrum. Like other treatment methods, certain devices were seen as unconventional at first, only to become widely accepted later. For example, many of the medical devices that make up the core of modern, scientifically based medicine, such as x-ray devices, at one time were considered highly experimental.
Most of today’s medical EM devices use relatively large levels of electrical, magnetic, or EM energy. The main topic of this chapter, however, is the use of the nonionizing portion of the EM spectrum, particularly at low levels, which is the focus of BEM research.
Nonionizing BEM medical applications may be classified according to whether they are thermal (heat producing in biologic tissue) or nonthermal. Thermal applications of nonionizing radiation (i.e., application of heat) include RF hyperthermia, laser and RF surgery, and RF diathermy.
The most important BEM modalities in alternative medicine are the nonthermal applications of nonionizing radiation. The term nonthermal is used with two different meanings in the medical and scientific literature. Biologically (or medically) nonthermal means that it “causes no significant gross tissue heating”; this is the most common usage. Physically (or scientifically) nonthermal means “below the thermal noise limit at physiological temperatures.” The energy level of thermal noise is much lower than that required to cause heating of tissue; thus, any physically nonthermal application is automatically biologically nonthermal.
All of the nonthermal applications of nonionizing radiation are nonthermal in the biological sense. That is, they cause no significant heating of tissue. Some of the newer, unconventional BEM applications are also physically nonthermal. A variety of alternative medical practices developed outside the United States employ nonionizing EM fields at nonthermal intensities. For instance, microwave resonance therapy, which is used primarily in Russia, employs low-intensity (either continuous or pulse-modulated), sinusoidal microwave radiation to treat a variety of conditions, including arthritis, ulcers, esophagitis, hypertension, chronic pain, cerebral palsy, neurological disorders, and side effects of cancer chemotherapy (Devyatkov et al., 1991). Thousands of people in Russia also have been treated by specific frequencies of extremely low-level microwaves applied at certain acupuncture points.
The mechanism of action of microwave resonance therapy is thought to involve modifications in cell membrane transport or production of chemical mediators or both. Although a sizable body of Russian-language literature on this technique already exists, no independent validation studies have been conducted in the West. However, if such treatments prove to be effective, current views on the role of information and thermal noise (i.e., order and disorder) in living systems, which hold that biological information is stored in molecular structures, may need revision. It may be that such information is stored at the level of the whole organism in the endogenous EM field, which may be used informationally in biological regulation and cellular communication (i.e., not due to energy content or power intensity). If exogenous, extremely low-level nonionizing fields with energy contents well below the thermal noise limit produce biological effects, they may be acting on the body in such a way that they alter the body’s own field. That is to say, biological information would be altered by the exogenous EM fields.
The eight major new (or “unconventional”) applications of nonthermal, nonionizing EM fields are as follows:
1. Bone repair.
2. Nerve stimulation.
3. Wound healing.
4. Treatment of osteoarthritis.
6. Tissue regeneration.
7. Immune system stimulation.
8. Neuroendocrine modulations.
These applications of BEM and the evidence for their efficacy are discussed in the following section.
Applications 1 through 5 above have been clinically tested and are in limited clinical use. On the basis of existing animal and cellular studies, applications 6 through 8 offer the potential for developing new clinical treatments, but clinical trials have not yet been conducted.
Three types of applied EM fields are known to promote healing of nonunion bone fractures (i.e., those that fail to heal spontaneously):
* Pulsed EM fields (PEMFs) and sinusoidal EM fields (AC fields).
* DC fields.
* Combined AC-DC magnetic fields tuned to ion-resonant frequencies (these are extremely low-intensity, physically nonthermal fields) (Weinstein et al., 1990).
Approval of the U.S. Food and Drug Administration (FDA) has been obtained on PEMF and DC applications and is pending for the AC-DC application. In PEMF and AC applications, the repetition frequencies used are in the ELF range (Bassett, 1989). In DC applications, magnetic field intensities range from 100 microgauss to 100 gauss (G), and electric currents range from less than 0.1 microampere to milliamperes (Baranowski and Black, 1987)._ FDA approval of these therapies covers only their use to promote healing of nonunion bone fractures, not to accelerate routine healing of uncomplicated fractures.
Efficacy of EM bone repair treatment has been confirmed in double-blind clinical trials (Barker et al., 1984; Sharrard, 1990). A conservative estimate is that as of 1985 more than 100,000 people had been treated with such devices (Bassett et al., 1974, 1982; Brighton et al., 1979, 1981; Goldenberg and Hansen, 1972; Hinsenkamp et al., 1985).
Stimulation and Measurement of Nerve Activity
These applications fall into the following seven categories:
1. Transcutaneous electrical nerve stimulation (TENS). In this medical application, two electrodes are applied to the skin via wires attached to a portable electrical generating device, which may be clipped to the patient’s belt (Hagfors and Hyme, 1975). Perhaps more than 100 types of FDA-approved devices in this category are currently available and used in physical therapy for pain relief. All of them operate on the same basis.
2. Transcranial electrostimulation (TCES). These devices are similar to the TENS units. They apply extremely low currents (below the nerve excitation threshold) to the brain via two electrodes applied to the head and are used for behavioral/psychological modification (e.g., to reduce symptoms of depression, anxiety, and insomnia) (Shealy et al., 1992). A recent meta-analysis covering at least 12 clinical trials selected from more than 100 published reports found that TCES can alleviate anxiety disorders (Klawansky et al., 1992). With support from the National Institutes of Health (NIH), TCES is under evaluation for alleviation of drug dependence.
3. Neuromagnetic stimulation. In this application, which has both diagnostic and therapeutic uses, a magnetic pulse is applied noninvasively to a part of the patient’s body to stimulate nerve activity. In diagnostic use, a pulse is applied to the cerebral cortex, and the patient’s physiological responses are monitored to obtain a dynamic picture of the brain-body interface (Hallett and Cohen, 1989). As a treatment modality, it is being used in lieu of electroshock therapy to treat certain types of affective disorder (e.g., major depression) and seizures (Anninos and Tsagas, 1991). Neuromagnetic stimulation also is used in nerve conduction studies for conditions such as carpal tunnel syndrome.
4. Electromyography. This diagnostic application detects electrical potentials associated with muscle contraction. Specific electrical patterns have been associated with certain abnormal states (e.g., denervated muscle). This method, along with electromyographic biofeedback, is being used to treat carpal tunnel syndrome and other movement disorders.
5. Electroencephalography. This neurodiagnostic application detects brainwaves. Coupled with EEG biofeedback it is used to treat a variety of conditions, such as learning disabilities, attention deficit and hyperactivity disorders, chronic alcoholism, and stroke.
6. Electroretinography. This diagnostic application monitors electrical potentials across the retina to assess eye movements. This is one of the few methods available for noninvasive monitoring of rapid eye movement sleep.
7. Low-energy emission therapy. This application uses an antenna positioned in the patient’s mouth to administer amplitude-modulated EM fields. It has been shown to affect the central nervous system, and pilot clinical studies show efficacy in treating insomnia (Hajdukovic et al., 1992) and hypertension (Pasche et al., 1989).
Soft-tissue Wound Healing
The following studies have demonstrated accelerated healing of soft-tissue wounds using DC, PEMF, and electrochemical modalities:
* When wound healing is abnormal (retarded or arrested), electric or magnetic field applications may trigger healing to occur. A review of several reports indicates that fields may be useful in this regard (Lee et al., 1993; Vodovnik and Karba, 1992).
* PEMFs have been used clinically to treat venous skin ulcers. Results of several double-blind studies showed that PEMF stimulation promotes cell activation and cell proliferation through an effect on the cell membrane, particularly on endothelial cells (Ieran et al., 1990; Stiller et al., 1992).
* ELF and RF fields are applied to accelerate wound healing. Since skin wounds have unique electrical potentials and currents, stimulation of these electrical factors by a variety of exogenous EM fields can aid in the healing process by causing dedifferentiation (i.e., conversion to a more primitive form) of the nearby cells followed by accelerated cell proliferation (O’Connor et al., 1990).
* An electrochemical treatment that provides scarless regenerative wound healing uses electricity solely to introduce active metallic ions, such as silver, into the tissue. The electric field plays no role itself (Becker, 1987, 1990, 1992).
* PEMF increases the rate of formation of epithelial (skin) cells in partially healed wounds (Mertz et al., 1988).
* AC EM fields promote the repair of injured vascular networks (Herbst et al., 1988).
* EM devices have been patented for treating atherosclerotic lesions (i.e., small blood clots that build up on the walls of arteries and cause cardiovascular disease) and to control tissue growth (Gordon, 1986; Liboff et al., 1992b).
In a recent clinical trial using a double-blind, randomized protocol with placebo control, osteoarthritis (primarily of the knee) treated noninvasively by pulsed 30-Hz, 60-G PEMFs showed the treatment group improved substantially more than the placebo group (Trock et al., 1993). It is believed that applied magnetic fields act to suppress inflammatory responses at the cell membrane level (O’Connor et al., 1990).
Electrical stimulation via acupuncture needles is often used as an enhancement or replacement for manual needling. Clinical benefits have been demonstrated for the use of electrical stimulation (electrostimulation) in combination with acupuncture as well as for electrostimulation applied directly to acupuncture points.
As an enhancement of acupuncture, a small-scale study showed electrostimulation with acupuncture to be beneficial in the treatment of post-operative pain (Christensen and Noreng, 1989). Other controlled studies have shown good success in using electrostimulation with acupuncture in the treatment of chemotherapy-induced sickness in cancer patients (Dundee and Ghaly, 1989). In addition, electrical stimulation with acupuncture was recently shown to be beneficial in the treatment of renal colic (Lee et al., 1992).
As a replacement for acupuncture, electrostimulation applied in a controlled study to acupuncture points by a TENS unit was effective in inducing uterine contractions in postterm pregnant women (Dunn and Rogers, 1989). Further, research with rats has shown that electrostimulation at such points can enhance peripheral motor nerve regeneration (McDevitt et al., 1987) and sensory nerve sprouting (Pomeranz et al., 1984).
Animal research in this area indicates that the body’s endogenous EM fields are involved in growth processes and that modifications of these fields can lead to modest regeneration of severed limbs (Becker, 1987; Becker and Spadero, 1972; Smith, 1967). Russian research and clinical applications, along with studies now under way in the United States, indicate that low-intensity microwaves apparently stimulate bone marrow stem cell division and may be useful in enhancing the effects of chemotherapy by maintaining the formation and development, or hematopoiesis, of various types of blood cells (Devyatkov et al., 1991).
The following studies are also relevant to the use of BEM for regeneration:
* PEMF applications to promote peripheral nerve regeneration (Orgel et al., 1992; Sisken, 1992).
* The “diapulse” method of using pulsed, high-frequency EM fields for human wrist nerve regeneration (Wilson et al., 1974).
* DC applications to promote rat spinal cord regeneration (Fehlings et al., 1992; Hurlbert and Tator, 1992).
* Swedish work showing that BEM promotes rat sciatic nerve regeneration (Kanje and Rusovan, 1992; Rusovan and Kanje, 1991, 1992; Rusovan et al., 1992).
During the past two decades, the effects of EM exposure on the immune system and its components have been extensively studied. While early studies indicated that long-term exposure to EM fields might negatively affect the immune system, there is promising new research showing that applied EM fields may be able to beneficially modulate immune responses. For example, studies with human lymphocytes show that exogenous EM or magnetic fields can produce changes in calcium transport (Walleczek, 1992) and cause mediation of the mitogenic response (i.e., the stimulation of the division of cellular nuclei; certain types of immune cells begin to divide and reproduce rapidly in response to certain stimuli, or mitogens). This finding has led to research investigating the possible augmentation by applied EM fields of a type of immune cell population called natural killer cells, which are important in helping the body fight against cancer and viruses (Cadossi et al., 1988a, 1988b; Cossarizza et al., 1989a, 1989b, 1989c).
Potential Neuroendocrine Modulations
Low-level PEMFs have typically been shown to suppress levels of melatonin, which is secreted by the pineal gland and is believed to regulate the body’s inner clock (Lerchl et al., 1990; Wilson et al., 1990b). Melatonin, as a hormone, is oncostatic (i.e., it stops cancer growth). Thus, if melatonin can be suppressed by certain magnetic fields, it also may be possible to employ magnetic fields with different characteristics to stimulate melatonin secretion for the treatment of cancer. Other applications may include use of EM fields to affect melatonin secretion to normalize circadian rhythms in people with jet lag and sleep cycle disturbances.
Table 2 provides an overview of selected citations to the refereed literature for these applications.
Future Research Opportunities
Although to date there is an extensive base of literature on the use of BEM for medical applications, the overall research strategy into this phenomenon has been quite fragmented. Because of BEM’s potential for the treatment of a wide range of conditions, an integrated research program is needed that includes both basic and clinical research in BEM. These two approaches should be pursued vigorously and simultaneously along parallel tracks.
Basic research is needed to refine or develop new BEM technologies with the aim of establishing the fundamental knowledge about the body’s endogenous EM fields and how they interact with clinically applied EM fields. A basic understanding of the BEM of the human body might provide insight into the scientific bioenergetic or bioinformational principles by which other areas of alternative medicine, such as homeopathy, acupuncture, and energetic therapies, may function. Furthermore, fundamental knowledge of BEM principles in the human body, in conjunction with psychophysiological states, might help facilitate understanding of mind-body regulation.
Clinical research, including preclinical assessments, is also essential, with the aim of bringing the most promising BEM treatments and diagnostics from limited use into widespread use as quickly as possible. Although a number of BEM devices show promise as new diagnostics or therapeutics, they must be tested on humans to show exactly when they are effective and when they are not. Moreover, measures of clinical effectiveness and safety are required for FDA approval of BEM medical devices. Ultimately, knowledge about the safety of new BEM medical devices can be ascertained only from the appropriate clinical trials.
The current status of basic research in BEM may be summarized as follows:
* Nonionizing, nonthermal exogenous EM fields exert measurable bioeffects in living organisms. In general, the organism’s response to applied EM fields is highly frequency specific and the dose-response curve is nonlinear (i.e., application of an additional amount of the EM field does not elicit a response of equal magnitude; the response eventually diminishes no matter how additional EM stimuli are applied). Extremely weak EM fields may, at the proper frequency and site of application, produce large effects that are either clinically beneficial or harmful.
* The cell membrane has been proposed as the primary site of transduction of EM field bioeffects. Relevant mechanisms may include changes in cell-membrane binding and transport processes, displacement or deformation of polarized molecules, modifications in the conformation of biological water (i.e., water that comprises organisms), and others.
* The physical mechanisms by which EM fields may act on biomolecules are far too complex to discuss here. However, the following references propose such physical mechanisms: Grundler et al., in press; Liboff, 1985, 1991; and Liboff et al., 1991.
* Endogenous nonthermal EM fields ranging from DC to the visible spectral region may be intimately involved in regulating physiological and biochemical processes.
Consequently, the following pressing needs should be addressed in developing a basic BEM research program:
* Standardized protocols for measuring dosages for therapeutically applied EM fields should be established and followed uniformly in BEM research. Protocols are needed for characterizing (i.e., defining and measuring) EM field sources (both exogenous and endogenous) and EM parameters of biological subjects. Such variables must be characterized in greater detail than is commonly practiced in clinical research. Artifacts caused by ambient EM fields in the laboratory environment (e.g., from power lines and laboratory equipment) must be avoided.
* In general, a balanced, strategic approach to basic research–including studies in humans, animals, and cells along with theoretical modeling and close collaboration with other investigators in alternative medicine–will produce the most valuable results in the long run.
* Many independent parameters characterize nonthermal nonionizing EM fields, including pulsed vs. nonpulsed and sinusoidal vs. other waveforms; frequency; phase; intensity (as a function of spatial position); voltage; and current. If multiple fields are combined, these parameters must be specified for each component. Additional parameters necessary for characterizing the medical application of EM fields include the site of application and the time course of exposure. All of these can be experimentally varied, producing an enormous range of possibilities. To date, there has been little systematic research to explore the potential biological effects of this vast array of applied field parameter characteristics.
Clinical trials of BEM-based treatments for the following conditions may yield useful results relatively soon: arthritis, psychophysiological states (including drug dependence and epilepsy), wound healing and regeneration, intractable pain, Parkinson’s disease, spinal cord injury, closed head injury, cerebral palsy (spasticity reduction), learning disabilities, headache, degenerative conditions associated with aging, cancer, and acquired immunodeficiency syndrome (AIDS).
EM fields may be applied clinically as the primary therapy or as adjuvant therapy along with other treatments in the conditions listed above. Effectiveness can be measured via the following clinical markers:
* In arthritis, the usual clinical criteria, including decrease of pain, less swelling, and thus a greater potential for mobility.
* In psychophysiological problems, relief from symptoms of drug withdrawal and alleviation of depressive anxiety and its symptoms.
* In epilepsy, return to greater normality in EEG, more normal sleep patterns, and reduction in required drug dosages.
* In wound healing and regeneration, repair of soft tissue and reduction of collagenous tissue in scar formation; regrowth via blastemal (primitive cell) formation and increase in tensile strength of surgical wounds; alleviation of decubitus chronic ulcers (bedsores); increased angiogenesis (regrowth of vascular tissue such as blood vessels); and healing of recalcitrant (i.e., unresponsive to treatment) chronic venous ulcers.
For instance, a short-term, double-blind clinical trial of magnetic field therapy could be based on the protocol of Trock et al. (1993) for osteoarthritis of the knee or elbow. This protocol is as follows:
* A suitable patient population is divided into treatment and control groups. Individual assignments are coded and remain unknown to patients, clinicians, and operators until treatment and assessment are complete.
* Pretreatment clinical markers are assessed by clinicians or by patients themselves or both.
* Treatments consist of 3 to 5 half-hour sessions each week for a total of 18 treatments over 5-6 weeks.
* During treatment, each patient inserts the affected limb into the opening of a Helmholtz coil (a solenoid about 12 inches in diameter and 6 inches long) and rests while appropriate currents are applied to the coil via a preset program.
* The treatment is noninvasive and painless; the patient feels nothing; there is no measurable transfer of heat to the patient.
* The control group follows the same procedure except that, unknown to operator and patient, a “dummy” apparatus (altered internally so that no current flows in the coil) is used.
* Patients’ posttreatment clinical markers are assessed.
* Appropriate data reduction (scoring of assessments, decoding of the treatment and control groups, and statistical analysis) is performed.
Clinical trials of BEM-based treatments for a variety of other conditions could follow a similar general outline.
Certain key issues or controversies surrounding BEM have inhibited progress in this field. These issues fall into several distinct areas: medical controversy, scientific controversy, barriers, and other issues.
A number of uncharacterized “black box” medical treatment and diagnostic devices–some legal and some illegal–have been associated with EM medical treatment. Whether they operate on the basis of BEM principles is unknown. Among these devices are the following: radionics devices, Lakhovsky multiple-wave oscillator, Priore’s machine, Rife’s inert gas discharge tubes, violet ray tubes, Reich’s orgone energy devices, EAV machines, and biocircuit devices. There are at least six alternative explanations for how these and other such devices operate: (1) They are ineffectual and are based on erroneous application of physical principles. (2) They may be operating on BEM principles, but they are uncharacterized. (3) They may operate on acoustic principles (sound or ultrasound waves) rather than BEM. (4) In the case of diagnostic devices, they may work by focusing the intuitive capacity of the practitioner. (5) In the case of long-distance applications, they may operate by means of nonlocal properties of consciousness of patient and practitioner. (6) They may be operating on the energy of some domain that is uncharacterized at present.
A recent survey (Eisenberg et al., 1993) showed that about 1 percent of the U.S. population used energy healing techniques that included a variety of EM devices. Indeed, more of the respondents in this 1990 survey used energy healing techniques than used homeopathy and acupuncture in the treatment of either serious or chronic disease. In addition to the use of devices by practitioners, a plethora of consumer medical products that use magnetic energy are purported to promote relaxation or to treat a variety of illnesses. For example, for the bed there are mattress pads impregnated with magnets; there are magnets to attach to the site of an athletic injury; and there are small pelletlike magnets to place over specific points on the body. Most of these so-called therapeutic magnets, also called biomagnets, come from Japan. However, no known published journal articles demonstrating effectiveness via clinical trials exist.
Some of the medical modalities discussed in this report, although presently accepted medically or legally in the United States, have not necessarily passed the most recent requirements of safety or effectiveness. FDA approval of a significant number of BEM-based devices, primarily those used in bone repair and neurostimulation, was “grandfathered.” That is, medical devices sold in the United States prior to the Medical Device Law of the late 1970s automatically received FDA approval for use in the same manner and for the same medical conditions for which they were used prior to the law’s enactment. Grandfathering by the FDA applies not only to BEM devices but to all devices covered by the Medical Device Law. However, neither the safety nor the effectiveness of grandfathered devices is established (i.e., they are approved on the basis of a “presumption” by the FDA, but they usually remain incompletely studied). Reexamination of devices in use, whether grandfathered or not, may be warranted.
There are three possible ways of resolving controversies associated with BEM and its application: (1) elucidating the fundamental principles underlying the device, or at least the historical basis for the development of the device; (2) conducting properly designed case control studies and clinical trials to validate effects that have been reported or claimed for BEM-based treatments; and (3) increasing the medical community’s awareness of well-documented, controlled clinical trials that indicate the effectiveness of specific BEM applications (see table 2).
Some physicists claim that low-intensity, nonionizing EM fields have no bioeffects other than resistive (joule) heating of tissue. One such argument is based on a physical model in which the only EM field parameter considered relevant to biological systems is power density (Adair, 1991). The argument asserts that measurable nonthermal bioeffects of EM fields are “impossible” because they contradict known physical laws or would require a “new physics” to explain them.
However, numerous independent experiments reported in the refereed-journal research literature conclusively establish that nonthermal bioeffects of low-intensity EM fields do indeed exist. Moreover, the experimental results lend support to certain new approaches in theoretical modeling of the interactions between EM fields and biological matter. Most researchers now feel that BEM bioeffects will become comprehensible not by forsaking physics but rather by developing more sophisticated, detailed models based on known physical laws, in which additional parameters (e.g., frequency, intensity, waveform, and field directionality) are taken into account.
The following barriers to BEM research exist:
* Members of NIH review panels in medical applications might not be adequately knowledgeable about alternative medical practices or BEM. This is the most serious barrier.
* Funding in BEM research is weighted heavily toward the study of hazards of EM fields; there is little funding for potential beneficial medical applications or the study of basic mechanisms of EM interactions with life processes. Also, the bulk of EM field research is administered by the Department of Defense and the Department of Energy, agencies with missions unrelated to medical research. The small amount of BEM work funded by NIH thus far has addressed mostly the hazards of EM fields. In late 1993 the National Institute of Environmental Health Sciences issued requests for grant application in the areas of (1) cellular effects of low-frequency EM fields and (2) effects of 60-Hz EM fields in vivo. The latter project is concerned solely with safety in power line and appliance exposures. However, the former apparently does not rule out the investigation of possible beneficial effects from low-frequency fields, although the focus is clearly on assessing previously reported effects of 60-Hz EM fields on cellular processes.
* Regulatory barriers to making new BEM devices available to practitioners are formidable. The approval process is slow and exorbitantly expensive even for conventional medical devices.
* Barriers in education include the following: (1) basic education in biological science is weak in physics, (2) undergraduate-and graduate-level programs in BEM are virtually nonexistent, and (3) multidisciplinary training is lacking in medicine and biology.
* The mainstream scientific and medical communities are basically conservative and respond to emerging disciplines, such as BEM, with reactions ranging from ignorance and apathy to open hostility. Consequently, accomplished senior researchers may not be aware of the opportunities for fruitful work in (or in collaboration with others in) BEM, while junior researchers may be reluctant to enter a field perceived by some as detrimental to career advancement.
Other key issues that need to be considered in developing a comprehensive research and development agenda for BEM include the following:
* Separate studies prepared for the Office of Technology Assessment, the National Institute of Occupational Safety and Health, and the Environmental Protection Agency have recommended independently that research on fundamental mechanisms of EM field interactions in humans receive high priority (Bierbaum and Peters, 1991; Nair et al., 1989; U.S. EPA, 1991). Moreover, a 1985 report prepared by scientists at the Centers for Devices and Radiological Health recommended that future research on EM field interactions with living systems “be directed at exploring beneficial medical applications of EMR (electromagnetic radiation) modulation of immune responses” (Budd and Czerski, 1985).
* Elucidation of the physical mechanisms of BEM medical modalities is the single most powerful key to developing efficient and optimal clinical intervention. Even a relatively small advance beyond present knowledge of fundamental mechanisms would be of considerable practical value. In addition, progress in the development of a mechanistic explanation of the effects of alternative medicine could increase its acceptability in the eyes of mainstream medicine and science.
* BEM potentially offers a powerful new approach to understanding the neuroendocrine and immunological bases of certain major medical problems (e.g., wound healing, cancer, and AIDS). However, substantial funding and time are required to perform the basic research needed in developing this approach.
* BEM may provide a comprehensive biophysical framework grounded in fundamental science, through which many alternative medical practices can be studied. BEM offers a promising starting point for scientifically exploring various traditional alternative medical systems (Becker and Marino, 1982).
Basic Research Priorities
The most fruitful topics for future basic research investigations of BEM may include the following:
* Developing assay methods based on EM field interactions in cells (e.g., for potassium transport, calcium transport, and cytotoxicity). These assays could then be applied to existing studies of such phenomena in cellular systems.
* Developing BEM-based treatments for osteoporosis, on basis of the large body of existing work on EM bone repair and other research (e.g., Brighton et al., 1985; Cruess and Bassett, 1983; Liboff et al., 1992a; MadroZero, 1990; Magee et al., 1991; Skerry et al., 1991). NASA researchers have already expressed interest in collaborative work to develop BEM treatments for weightlessness-induced osteoporosis.
* Measuring neurobiochemical changes in the blood in response to microcurrent skin stimulation in animals or humans with different frequencies, waveforms, and carrier waves. Such measurements should be made for preclinical evaluation of neurostimulation devices.
* Furthering studies of mechanisms of EM field interactions in cells and tissues with emphasis on coherent or cooperative states and resonant phenomena in biomolecules; and on coherent brainwave states and other long-range interactions in biological systems.
* Studying the role of water as a mediator in biological interactions with emphasis on the quantum EM aspects of its conformation (i.e., “structure,” as implied in some forms of homeopathy). The response of biologic water to EM fields should be studied experimentally. A novel informational capacity of water in relation to EM bioeffects may provide insights into homeopathy and healer interactions (i.e., “laying on of hands”).
* Studying in detail the role of the body’s internally generated (endogenous) EM fields and the body’s other natural electromagnetic parameters (see the “Manual Healing Methods” chapter). Knowledge of such processes should be applied to develop novel diagnostic methods and to understand alternative medical treatments such as acupuncture, electroacupuncture, and biofield therapies. Furthermore, exploratory research on the role of the body’s energy fields in relation to the role of states of consciousness in health and healing should be launched.
* Establishing a knowledge base (an intelligent database) to provide convenient access to all significant BEM work in both basic and clinical research.
* Performing systematic reviews as well as meta-analytic reviews of existing BEM studies to identify the frequency and quality of research concerning BEM as well as most promising clinical end points for BEM treatments in humans.
Just as exposure to high-energy radiation has unquestioned hazards, radiation has long been a key weapon in the fight against many types of cancers. Likewise, although there are indications that some EM fields may be hazardous, there is now increasing evidence that there are beneficial bioeffects of certain low-intensity nonthermal EM fields.
In clinical practice, BEM applications offer the possibility of more economical and more effective diagnostics and new noninvasive therapies for medical problems, including those considered intractable or recalcitrant to conventional treatments. The sizable body of recent work cited in this chapter has established the feasibility of treatments based on BEM, although the mainstream medical community is largely unaware of this work.
In biomedical research, BEM can provide a better understanding of fundamental mechanisms of communication and regulation at levels ranging from intracellular to organismic. Improved knowledge of fundamental mechanisms of EM field interactions could lead directly to major advances in diagnostic and treatment methods.
In the study of other alternative medical modalities, BEM offers a unified conceptual framework that may help explain how certain diagnostic and therapeutic techniques (e.g., acupuncture, homeopathy, certain types of ethnomedicine, and healer effects) may produce results that are difficult to understand from a more conventional viewpoint. These areas of alternative medicine are currently based entirely on empirical (i.e., experimentation and observation rather than theory) and phenomenological (i.e., the classification and description of any fact, circumstance, or experience without any attempt at explanation) approaches. Thus, their future development could be accelerated as a scientific understanding if their mechanisms of action are ascertained.
Adair, R.K. 1991. Constraints on biological effects of weak extremely low-frequency electromagnetic fields. Physical Review 43:1039-1048.
Adey, W.R. 1992. Collective properties of cell membranes. In B. Norden and C. Ramel, eds. Interaction Mechanisms of Low-level Electromagnetic Fields in Living Systems. Symposium, Royal Swedish Academy of Sciences, Stockholm (pp. 47-77). Oxford University Press, New York.
Adey, W.R., and A.F. Lawrence, eds. 1984. Nonlinear Electrodynamics in Biological Systems (conference proceedings). Plenum Press, New York.
Albertini, A., P. Zucchini, G. Nocra, R. Carossi, and A. Pierangeli. 1990. Effect of PEMF on irreversible ischemic injury following coronary artery occlusion in rats. Transactions of Bioelectrical Repair and Growth Society 10:20.
Anninos, P.A., and N. Tsagas. 1991. Magnetic stimulation in the treatment of partial seizures. Int. J. Neurosci. 60:141-171.
Baranowski, T.J., and J. Black. 1987. Stimulation of osteogenesis. In M. Blank and E. Findl, eds. Mechanistic Approaches to Interactions of Electric and Electromagnetic Fields With Living Systems (pp. 399-416). Plenum Press, New York.
Barker, A.T., R.A. Dixon, W.J.W. Sharrard, and M.L. Sutcliffe. 1984. Pulsed magnetic field therapy for tibial non-union: interim results of a double-blind trial. Lancet. 1 (8384):994-996.
Bassett, C.A.L. 1989. Fundamental and practical aspects of therapeutic uses of pulsed electromagnetic fields (PEMFs). CRC Critical Reviews in Biomedical Engineering 17:451-529.
Bassett, C.A.L., S.N. Mitchell, and S.R. Gaston. 1982. Pulsing electromagnetic field treatment in ununited fractures and failed arthrodoses. JAMA 247:623-628.
Bassett, C.A.L., R.D. Pawluk, and A.A. Pilla. 1974. Augmentation of bone repair by inductively coupled electromagnetic fields. Science 184:575-577.
Becker, R.O. 1987. The effect of electrically generated silver ions on human cells. Proceedings of 1st International Conference on Gold and Silver in Medicine, Bethesda, Md., May 13-14, pp. 227-243.
Becker, R.O. 1990. A technique for producing regenerative healing in humans. Frontier Perspectives 1(2):1-2.
Becker, R.O. 1992. Effect of anodally generated silver ions on fibrosarcoma cells. Electro-and Magnetobiology 11:57-65.
Becker, R.O., and A.A. Marino. 1982. Electromagnetism and Life. State University of New York Press, Albany, New York.
Becker, R.O., and J.A. Spadero. 1972. Electrical stimulation of partial limb regeneration in mammals. Bull. N.Y. Acad. Med. 48:627-641.
Bierbaum, P.J., and J.M. Peters, eds. 1991. Proceedings of the Scientific Workshop on the Health Effects of Electric and Magnetic Fields on Workers. Cincinnati, Ohio, January 30-31. National Institute of Occupational Safety and Health (NIOSH) Report No. 91-111. NTIS Order No. PB-91-173-351/A13. National Technical Information Service, Springfield, Va.
Blank, M., ed. 1993. Electricity and Magnetism in Biology and Medicine. Proceedings of the 1st World Congress for Electricity and Magnetism in Biology and Medicine, Orlando, Fla., June 14-19, 1992. San Francisco Press, Inc., San Francisco.
Blank, M., and E. Findl, eds. 1987. Mechanistic Approaches to Interactions of Electric and Electromagnetic Fields With Living Systems. Plenum Press, New York.
Brayman, A., and M. Miller. 1989. Proportionality of 60-Hz electric field bioeffect severity to average induced transmembrane potential magnitude in a root model system. Radiat. Res. 117:207-213.
Brayman, A., and M. Miller. 1990. 60-Hz electric field exposure inhibits net apparent H-ion excretion from excised roots of Zea mays L. Radiat. Res. 123:22-31.
Brighton, C.T., J. Black, Z.B. Friedenberg, J.L. Esterhai, L. Day, and J.F. Connally. 1981. A multicenter study of the treatment of nonunion with constant direct current. J. Bone Joint Surg. (Br.) 63A:2-12.
Brighton, C.T., J. Black, and S.R. Pollack, eds. 1979. Electrical Properties of Bone and Cartilage: Experimental Effects and Clinical Applications. Grune and Stratton, Inc., New York.
Brighton, C.T., M.J. Katz, S.R. Goll, C.E. Nichols, and S.R. Pollack. 1985. Prevention and treatment of sciatic denervation disuse osteoporosis in the rat tibia with capacitively coupled electrical stimulation. Bone 6:87-97.
Brighton, C.T., and S.R. Pollack, eds. 1991. Electromagnetics in Medicine and Biology. San Francisco Press, Inc., San Francisco.
Brown, H.D., and S.K. Chattpadhyay. 1991. EM-field effect upon properties of NADPH-cytochrome P-450 reductase with model substrates. Cancer Biochem. Biophys. 12(3):211-215.
Budd, R.A., and P. Czerski. 1985. Modulation of mammalian immunity by electromagnetic radiation. J. Microw. Power Electromagn. Energy 20:217-231.
Cadossi, R., G. Emilia, and G. Torelli. 1988a. Lymphocytes and pulsing magnetic fields. In A.A. Marino, ed. Modern Bioelectricity. Marcel Dekker, Inc., New York.
Cadossi, R., R. Iverson, V.R. Hentz, P. Zucchini, G. Emilia, and G. Torelli. 1988b. Effect of low-frequency low-energy pulsing electromagnetic fields on mice undergoing bone marrow transplantation. International Journal of Immunopathology and Pharmacology 1:57-62.
Chen, J., and O.P. Gandhi. 1989. RF currents in an anatomically based model of a human for plane-wave exposures (20-100 MHz). Health Phys. 57(1):89-98.
Christensen, P.A., and M. Noreng. 1989. Electroacupuncture and postoperative pain. Br. J. Anaesth. 62:258-262.
Chwirot, W.B. 1988. Ultraweak photon emission and anther meiotic cycle in Larix europaea (experimental investigation of Nagl and Popp’s electromagnetic model of differentiation). Experientia 44:594-599.
Chwirot, W.B., R.S. Dygdala, and S. Chwirot. 1987. Quasi-monochromatic-light-induced photon emission from microsporocytes of larch shows oscillating decay behavior predicted by the electromagnetic model of differentiation. Cytobios 47:137-146.
Cohen, M.M., A. Kunska, J.A. Astemborsky, and D. McCulloch. 1986. The effect of low-level 60-Hz electromagnetic fields on human lymphoid cells. Circ. Res. 172:177-184.
Cossarizza, A., D. Monti, F. Bersani, et al. 1989a. Extremely low-frequency pulsed electromagnetic fields increase cell proliferation in lymphocytes from young and aged subjects. Biochem. Biophys. Res. Commun. 160:692-698.
Cossarizza, A., D. Monti, F. Bersani, et al. 1989b. Extremely low-frequency pulsed electromagnetic fields increase interleukin-2 (IL-2) utilization and IL-2 receptor expression in mitogen-stimulated human lymphocytes from old subjects. FEBS Lett. 248:141-144.
Cossarizza, A., D. Monti, P. Sola, et al. 1989c. DNA repair after irradiation in lymphocytes exposed to low-frequency pulsed electromagnetic fields. Radiat. Res. 118:161-168.
Cruess, R.L., and C.A.L. Bassett. 1983. The effect of pulsing electromagnetic fields on bone metabolism in experimental disuse osteoporosis. Clin. Orthop. 173:245-250.
De Loecker, W., P.H. Delport, and N. Cheng. 1989. Effects of pulsed electromagnetic fields on rat skin metabolism. Biochim. Biophys. Acta 982:9-14.
Devyatkov, N.D., Y.V. Gulyaev, et al. 1991. Digest of Papers. International Symposium on Millimeter Waves of Non-Thermal Intensity in Medicine. Cosponsored by Research and Development Association “ISTOK” and Research Institute of U.S.S.R. Ministry of Electronic Industry (“ORION”). Moscow, October 3-6. (In Russian.)
Dundee, J.W., and R.G. Ghaly. 1989. Acupuncture prophylaxis of cancer chemotherapy-induced sickness. J. R. Soc. Med. 82:268-271.
Dunn, P.A., and D. Rogers. 1989. Transcutaneous electrical nerve stimulation at acupuncture points in the induction of uterine contractions. Obstet. Gynecol. 73:286-290.
Easterly, C. 1982. Cardiovascular risk from exposure to static magnetic fields. American Industrial Hygiene Association Journal 43:533-539.
Eisenberg, D.M., R.C. Kessler, C. Foster, et al. 1993. Unconventional medicine in the United States: prevalence, costs, and patterns of use. N. Engl. J. Med. 328:246-252.
Fehlings, M.G., R.J. Hurlbert, and C.H. Tator. 1992. An examination of direct current fields for the treatment of spinal cord injury. Paper presented at the 1st World Congress for Electricity and Magnetism in Biology and Medicine, Orlando, Fla., June 14-19.
Feinendegen, L.E. and H. Muhlensiepen. 1987. In vivo enzyme control through a strong stationary magnetic field: The case of thymidine kinase in mouse bone marrow cells. Int. J. Radiat. Biol. 52(3):469-479.
Foxall, P.J.D., G.H. Neild, F.D. Thompson, and J.K. Nicholson. 1991. High-resolution NMR spectroscopy of fluid from polycystic kidneys suggests reversed polarity of cyst epithelial cells. Journal of the American Society of Nephrology 2(3):252.
Goldenberg, D.M., and H.J. Hansen. 1972. Electric enhancement of bone healing. Science 175:1118-1120.
Goodman, R., L. Wei, J. Xu, and A. Henderson. 1989. Exposures of human cells to low-frequency electromagnetic fields results in quantitative changes in transcripts. Biochim. Biophys. Acta 1009:216-220.
Gordon, R.T. 1986. Process for the Treatment of Atherosclerotic Lesions. U.S. Patent No. 4,622,953, November 18.
Grande, D.A., F.P. Magee, A.M. Weinstein, and B.R. McLeod. 1991. The effect of low-energy combined AC and DC magnetic fields on articular cartilage metabolism. In C.T. Brighton and S.R. Pollack, eds. Electromagnetics in Medicine and Biology. San Francisco Press, Inc., San Francisco.
Greene, J.J., W.J. Skowronski, J.M. Mullins, and R.M. Nardone. 1991. Delineation of electric and magnetic field effects of extremely low frequency electromagnetic radiation on transcription. Biomedical and Biophysical Research Communications 174(2):742-749.
Grundler, W., F. Kaiser, F. Keilmann, and J. Walleczek. In press. Mechanisms of electromagnetic interaction with cellular systems. Naturwissenschaften. From a workshop sponsored by the Deutsche Forschungsgemeinschaft (DFG) at the Max-Planck-Institut fhr Festk`rperforschung, Stuttgart, Germany, September 11-12.
Guy, A.W. 1987. Dosimetry association with exposure to non-ionizing radiation: very low frequency to microwaves. Health Phys. 53(6):569-584.
Hagfors, N.R., and A.C. Hyme. 1975. Method and structure of preventing and treating ileus, and reducing acute pain by electrical pulse stimulation. U.S. Patent No. 3,911,930, October 14.
Hajdukovic, R., M. Mitler, B. Pasche, and M. Erman. 1992. Effects of low-energy emission therapy (LEET) on sleep structure (abstract). Sleep Research 21:206.
Hallett, M., and L.G. Cohen. 1989. Magnetism: a new method for stimulation of nerve and brain. JAMA 262 (4):538-541.
Herbst, E., B.F. Sisken, and H.Z. Wang. 1988. Assessment of vascular network in rat skin flaps subjected to sinusoidal EMFs using image analysis techniques. Transactions of the 8th Annual Meeting of the Bioelectrical Repair and Growth Society. Washington, D.C., October 9-12.
Hinsenkamp, M., J. Ryaby, and F. Burny. 1985. Treatment of nonunion by pulsing electromagnetic fields: European multicenter study of 308 cases. Reconstr. Surg. Traumatol. 19:147-151.
Horton, P., J.T. Ryaby, F.P. Magee, and A.M. Weinstein. 1992. Stimulation of specific neuronal differentiation proteins in PC12 cells by combined AC/DC magnetic fields. Presented at the 1st World Congress for Electricity and Magnetism in Biology and Medicine, Orlando, Fla., June 14-19.
Huraki, Y., N. Endo, M. Takigawa, A. Asada, H. Takahashe, and F. Suzuki. 1987. Enhanced responsiveness to parathyroid hormone and induction of functional differentiation of cultured rabbit costal chondrocytes by a pulsed electromagnetic field. Biochim. Biophys. Acta 931:94-110.
Hurlbert, R.J., and C.H. Tator. 1992. Effect of disc vs. cuff electrode configuration on tolerance of the rat spinal cord to DC stimulation. Paper presented at the 1st World Congress for Electricity and Magnetism in Biology and Medicine, Orlando, Fla., June 14-19.
Ieran, M., S. Zaffuto, M. Bagnacani, M. Annovi, A. Moratti, and R. Cadossi. 1990. Effect of low-frequency pulsing electromagnetic fields on skin ulcers of venous origin in humans: a double-blind study. J. Orthop. Res. 8:276-282.
Im, M.J., and J.E. Hoopes. 1991. Effects of electrical stimulation on ischemia/reperfusion injury in rat skin. In C.T. Brighton and S.R. Pollack, eds. Electromagnetics in Medicine and Biology. San Francisco Press, Inc., San Francisco.
Kanje, M., and A. Rusovan. 1992. Reversal of the stimulation of magnetic field exposure on regeneration of the rat sciatic nerve by a Ca2+ antagonist. Paper presented at the 1st World Congress for Electricity and Magnetism in Biology and Medicine, Orlando, Fla., June 14-19.
Klawansky, S., A. Yueng, C. Berkey, N. Shah, C. Zachery, and T.C. Chalmers. 1992. Meta-analysis of randomized control trials of the efficacy of cranial electrostimulation in treating psychological and physiological conditions. Report of the Technology Assessment Group, Department of Health Policy and Management, Harvard University School of Public Health, August 28.
Kraus, W. 1992. The treatment of pathological bone lesion with nonthermal, extremely low frequency electromagnetic fields. Bioelectrochemistry and Bioenergetics 27:321-339.
Lee, R.C., D.J. Canaday, and H. Doong. 1993. A review of the biophysical basis for the clinical application of electric fields in soft tissue repair. J. Burn Care Rehabil. 14:319-335.
Lee, Y.H., W.C. Lee, M.T. Chen, et al. 1992. Acupuncture in the treatment of renal colic. J. Urol. 147:16-18.
Lerchl, A., K.O. Nonaka, K.A. Stokkan, and R.J. Reiter. 1990. Marked rapid alterations in nocturnal pineal serotonin metabolism in mice and rats exposed to weak intermittent magnetic fields. Biochem. Biophys. Res. Commun. 169:102-108.
Liboff, A.R. 1985. Geomagnetic cyclotron resonance in living cells. J. of Biol. Phys. 13:99-104.
Liboff, A.R. 1991. The cyclotron resonance hypothesis: experimental evidence and theoretical constraints. In C. Ramel and B. Norden, eds. Interaction Mechanisms of Low-Level Electromagnetic Fields With Living Systems. Oxford University Press, London, pp. 130-147.
Liboff, A.R., B.R. McLeod, and S.D. Smith. 1991. Resonance transport in membranes. In C.T. Brighton and S.R. Pollack, eds. Electromagnetics in Medicine and Biology. San Francisco Press, Inc., San Francisco.
Liboff, A.R., B.R. McLeod, and S.D. Smith. 1992a. Techniques for Controlling Osteoporosis Using Noninvasive Magnetic Fields. U.S. Patent No. 5,100,373, March 31.
Liboff, A.R., B.R. McLeod, and S.D. Smith. 1992b. Method and Apparatus for Controlling Tissue Growth with an Applied Fluctuating Magnetic Field, U.S. Patent No. 5,123,898, June 23.
Liboff, A.R., R.A. Rinaldi, eds. 1974. Electrically mediated growth mechanisms in living systems. Ann. N.Y. Acad. Sci. 238(October 11).
Liburdy, R.P., and T.S. Tenforde. 1986. Magnetic field-induced drug permeability in liposome vesicles. Radiat. Res. 108:102-111.
MadroZero, A. 1990. Influence of magnetic fields on calcium salts crystal formation: an explanation of the “pulsed electromagnetic field” technique for bone healing. J. Biomed. Eng. 12:410-412.
Magee, F.P., A.M. Weinstein, R.J. Fitzsimmons, D.J. Baylink, and B.R. McLeod. 1991. The use of low-energy combined AC and DC magnetic fields in the prevention of osteopenia. In C.T. Brighton and S.R. Pollack, eds. Electromagnetics in Medicine and Biology. San Francisco Press, Inc., San Francisco.
Marino, A.A., ed. 1988. Modern Bioelectricity. Marcel Dekker, Inc., New York.
Marron, M.T., E.M. Goodman, P.T. Sharpe, and B. Greenebaum. 1988. Low-frequency electric and magnetic fields have different effects on the cell surface. FEBS Lett. 230(1-2):13-16.
Mathew, R., and S. Rumar. The non-exponential decay pattern of the weak luminescence from seedlings in Cicer arietinum L. stimulated by pulsating electric fields. Experientia. In press.
McDevitt, L., P. Fortner, and B. Pomeranz. 1987. Application of weak electrical field to the hindpaw enhances sciatic motor-nerve regeneration in the adult rat. Brain Res. 416:308-314.
Mertz, P.M., S.C. Davis, and W.H. Eaglstein. 1988. Pulsed electrical stimulation increases the rate of epithelialization in partial thickness wounds. Transactions of the 8th Annual Meeting of the Bioelectrical Repair and Growth Society, Washington, D.C., October 9-12.
Miklavcic, D., S. Rebersek, G. Sersa, et al. 1991. Nonthermal antitumor effect of electrical direct current on murine fibrosarcoma SA-1 tumor model. In C.T. Brighton and S.R. Pollack, eds. Electromagnetics in Medicine and Biology. San Francisco Press, Inc., San Francisco.
Nair, I., M.G. Morgan, and H.K. Florig. 1989. Biological Effects of Power Frequency Electric and Magnetic Fields (Background Paper). Office of Technology Assessment, Report No. OTA-BP-E-53. U.S. Government Printing Office, Washington, D.C.
O’Connor, M.E., R.H.C. Bentall, and J.C. Monahan, eds. 1990. Emerging Electromagnetic Medicine conference proceedings. Springer-Verlag, New York.
O’Connor, M.E., and R.H. Lovely, eds. 1988. Electromagnetic Fields and Neurobehavioral Function. Alan R. Liss, Inc., New York.
Omote, Y., M. Hosokawa, M. Komatsumoto, et al. 1990. Treatment of experimental tumors with a combination of a pulsing magnetic field and an antitumor drug. Jpn. J. Cancer Res. 81:956-961.
Onuma, E., and S. Hui. 1988. Electric field-directed cell shape changes, displacement, and cytoskeletal reorganization are calcium dependent. J. Cell Biol. 106:2067-2075.
Orgel, M.G., R.J. Zienowicz, B.A. Thomas, and W.H. Kurtz, 1992. Peripheral nerve transection injury: the role of electromagnetic field therapy. Paper presented at the 1st World Congress for Electricity and Magnetism in Biology and Medicine, Orlando, Fla., June 14-19.
Papatheofanis, F.J., and B.J. Papatheofanis. 1989. Acid and alkaline phosphase activity in bone following intense magnetic field irradiation of short duration. Int. J. Radiat. Biol. 55(6):1033-1035.
Pasche, B., T.P. Lebet, A. Barbault, C. Rossel, and N. Kuster. 1989. Electroencephalographic changes and blood pressure lowering effect of low energy emission therapy (abstract). Bioelectromagnetics Society Proceedings, F-3-5.
Phillips, J.L., and L. McChesney. 1991. Effect of 72-Hz pulsed magnetic field exposure on macromolecular synthesis in CCRF-CEM cells. Cancer Biochem. Biophys. 12:1-7.
Pollack, S.R., C.T. Brighton, D. Plenkowski, and N.J. Griffith. 1991. Electromagnetic Method and Apparatus for Healing Living Tissue. U.S. Patent No. 5,014,699, May 14.
Pomeranz, B., M. Mullen, and H. Markus. 1984. Effect of applied electrical fields on sprouting of intact saphenous nerve in adult rat. Brain Res. 303:331-336.
Popp, F.A., A.A. Gurwitsch, H. Inaba, et al. 1988. Biophoton emission (multiauthor review). Experientia 44:543-600.
Popp, F.A., K.H. Li, and Q. Gu, eds. 1992. Recent Advances in Biophoton Research and Its Applications. World Scientific Publishing Co., Singapore and New York.
Popp, F.A., W. Nagl, K.H. Li, et al. 1984. Biophoton emission: new evidence for coherence and DNA as source. Cell Biophys. 6:33-52.
Ramel, C., and B. Norden, eds. 1991. Interaction Mechanisms of Low-Level Electromagnetic Fields With Living Systems. Oxford University Press, London.
Rodemann, H.P., K. Bayreuther, and G. Pfleiderer. 1989. The differentiation of normal and transformed human fibroblasts in vitro is influenced by electromagnetic fields. Exp. Cell Res. 182:610-621.
Rosenthal, M., and G. Obe. 1989. Effects of 50-Hz electromagnetic fields on proliferation and on chromosomal alterations in human peripheral lymphocytes untreated or pretreated with chemical mutagens. Mutat. Res. 210:329-335.
Rusovan, A., and M. Kanje. 1991. Stimulation of regeneration of the rat sciatic nerve by 50-Hz sinusoidal magnetic fields. Exp. Neurol. 112:312-316.
Rusovan, A., and M. Kanje. 1992. D600, a Ca2+ antagonist, prevents stimulation of nerve regeneration by magnetic fields. NeuroReport 3:813-814.
Rusovan, A., M. Kanje, and K.H. Mild. 1992. The stimulatory effect of magnetic fields on regeneration of the rat sciatic nerve is frequency dependent. Exp. Neurol. 117:81-84.
Ryaby, J.T., D.A. Grande, F.P. Magee, and A.M. Weinstein. 1992. The effect of combined AC/DC magnetic fields on resting articular cartilage metabolism. Presented at the 1st World Congress for Electricity and Magnetism in Biology and Medicine, Orlando, Fla., June 14-19.
Sharrard, W.J.W. 1990. A double-blind trial of pulsed electromagnetic fields for delayed union of tibial fractures. J. Bone Joint Surg. (Br.) 72B:347-355.
Shealy, N., R. Cady, D. Veehoff, et al. 1992. Neuro-chemistry of depression. American Journal of Pain Management 2:31-36.
Short, W.O., L. Goodwill, C.W. Taylor, et al. 1992. Alteration of human tumor cell adhesion by high-strength static magnetic fields. Invest. Radiol. 27:836-840.
Sisken, B.F. 1992. Nerve regeneration: implications for clinical applications of electrical stimulation. Paper presented at the 1st World Congress for Electricity and Magnetism in Biology and Medicine, Orlando, Fla., June 14-19.
Skerry, T.M., M.J. Pead, M.J., and L.E. Lanyon. 1991. Modulation of bone loss during disuse by pulsed electromagnetic fields. J. Orthop. Res. 9:600-608.
Smith, S.D. 1967. Induction of partial limb regeneration in Arana pipicus by galvanic stimulation. Anat. Rec. 158:89-97.
Stiller, M.J., G.H. Pak, J.L. Shupack, S. Thaler, C. Kenny, and L. Jondreau. 1992. A portable pulsed electromagnetic field (PEMF) device to enhance healing of recalcitrant venous ulcers: a double-blind placebo-controlled clinical trial. Br. J. Dermatol. 127:147-154.
Subramanian, M., C.H. Sutton, B. Greenebaum, and B.F. Sisken. 1991. Interaction of electromagnetic fields and nerve growth factor on nerve regeneration in vitro. In C.T. Brighton and S.R. Pollack, eds. Electromagnetics in Medicine and Biology. San Francisco Press, Inc., San Francisco.
Takahashi, K., I. Kaneko, and E. Fukada. 1987. Influence of pulsing electromagnetic field on the frequency of sister-chromatid exchanges in cultural mammalian cells. Experientia 43:331-332.
Tenforde, T.S., and W.T. Kaune. 1987. Interaction of extremely low frequency electric and magnetic fields with humans. Health Phys. 53:585-606.
Thomas, J.R., J. Schrot, and A.R. Liboff. 1986. Low-intensity magnetic fields alter operant behavior in rats. Bioelectromagnetics 7:349.
Trock, D.H., A.J. Bollet, R.H. Dyer, Jr., L.P. Fielding, W.K. Miner, and R. Markoll. 1993. A double-blind trial of the clinical effects of pulsed electromagnetic fields in osteoarthritis. J. Rheumatol. 20:456-460.
U.S. Environmental Protection Agency. 1991. Evaluation of the Potential Carcinogenicity of Electromagnetic Fields. Report #EPA/600/6-90/05B. Unreleased preliminary draft (March).
Vodovnik, L., and R. Karba. 1992. Treatment of chronic wounds by means of electric and electromagnetic fields. Part 1: literature review. Med. Biol. Eng. and Comput. (May):257-266.
Walleczek, J. 1992. Electromagnetic field effects on cells of the immune system: the role of calcium signalling. FASEB Lett. 6:3177-3185.
Weinstein, A.M., B.R. McLeod, S.D. Smith, and A.R. Liboff. 1990. Ion resonance-tuned electromagnetic fields increase healing rate in ostectomized rabbits. Abstracts of 36th Annual Meeting of Orthopedic Research, February 5-8, 1990, New Orleans.
Wijk, R.V., and D.H.J. Schamhart. 1988. Regulatory aspects of low-intensity photon emission. Experientia 44:586-593.
Wilson, B.W., R.G. Stevens, and L.E. Anderson, eds. 1990a. Extremely Low Frequency Electromagnetic Fields: The Question of Cancer. Battelle Press, Columbus, Ohio.
Wilson, B.W., C.W. Wright, J.E. Morris, et al. 1990b. Evidence for an effect of ELF electromagnetic fields on human pineal gland function. J. Pineal Res. 9:259-269.
Wilson, D.H., P. Jagdeesh, P.P. Newman, and D.G.F. Harriman. 1974. The effects of pulsed electromagnetic energy on peripheral nerve regeneration. Ann. N.Y. Acad. Sci. 238:575-585.
Yen-Patton, G.P.A., W.F. Patton, D.M. Beer, and B.S. Jacobson. 1988. Endothelial cell response to pulsed electromagnetic fields: stimulation of growth rate and angiogenesis in vitro. J. Cell. Physiol. 134:37-46.
Table 1. Electromagnetic Spectrum
Frequency range (Hz)* Classification Biological effect
0 Direct current Nonionizing
0 – 300 Extremely low frequency Nonionizing
300 – 104 Low frequency Nonionizing
104 – 109 Radio frequency Nonionizing
109 – 1012 Microwave and radar bands Nonionizing
1012 – 4 x 1014 Infrared band Nonionizing
4 x 1014 – 7 x 1014 Visible light Weakly ionizing
7 x 1014 – 1018 Ultraviolet band Weakly ionizing
1018 – 1020 X rays Strongly ionizing
Over 1020 Gamma rays Strongly ionizing
* Division of the EM spectrum into frequency bands is based on conventional but arbitrary usage in various disciplines.
Table 2. Selected Literature Citations on Biomedical Effects of Nonthermal EM Fields
Frequency range of EM fields
Location or type of bioeffect_
DC_ELF, including sinusoidal, pulsed, and mixed_
RF and microwave_
IR, visible, and UV light_
Review articles and monographs___
Bone and cartilage, including treatments for bone repair and osteoporosis_Brighton et al., 1981;
Baranowsi & Black, 1987;
Papatheofanis, 1989_Bassett et al., 1982;
Barker et al., 1984;
Brighton et al., 1985;
Hinsenkamp et al., 1985;
Huraki et al., 1987;
Grande et al., 1991;
Magee et al., 1991;
Pollack et al., 1991;
Skerry et al., 1991;
Ryaby et al., 1992___Brighton et al., 1979__
Soft tissue, including wound healing, regeneratrion, and vasculartissue effects_Becker, 1987;
Vodovnik & Karba, 1992_Gordon, 1986;
Herbst et al., 1988;
Mertz et al., 1988;
YenPatton et al., 1988;
Albertini et al., 1990;
Ieran et al., 1990;
Im & Hoopes, 1991;
Liboff et al., 1992b;
Stiller et al., 1992;
Vodovnik & Karba, 1992_Devyatkov et al., 1991__Vodovnik & Karba, 1992__
Neural tissue, including nerve growth and regeneration__Wilson et al., 1974;
Rusovan & Kanje, 1991;
Subramanian et al., 1991;
Horton et al., 1992;
Rusovan & Kanje, 1992;
Rusovan et al., 1992_____
Neural stimulation effects, including TENS and TCES__Hagfors & Hyme, 1975;
Hallett & Cohen, 1989;
Anninos & Tsagas, 1991;
Klawansky et al., 1992_____
Psychophysiological and behavioral effects___Pasche et al., 1989;
Devyatkov et al., 1991;
Hajdukovic et al., 1992_Thomas et al., 1986_O’Connor & Lovely, 1988__
Electroacupuncture_McDevitt et al., 1987_Pomeranz et al., 1984;
Christensen & Noreng, 1989;
Dundee & Ghaly, 1989;
Lee et al., 1992_____
Neuroendocrine effects, including melatonin modifications_Feinendegen & Muhlensiepen, 1987_Lerchl et al., 1990;
Wilson et al., 1990a, 1990b___O’Connor & Lovely, 1988__
Immune system effects__Cadossi et al., 1988a;
Cadossi et al., 1988b;
Cossarizza et al., 1989a;
Cossarizza et al., 1989b;
Rosenthal & Obe, 1989;
Phillips & McChesney, 1991;
Arthritis treatments__Grande et al., 1991;
Trock et al., 1993_Devyatkov et al., 1991____
Cellular and subcellular effects, including effects on cell membrane, genetic system, and tumors_Easterly, 1982;
Liburdy & Tenforde, 1986;
Foxall et al., 1991;
Miklavcic et al., 1991;
Short et al., 1992_Cohen et al., 1986;
Takahashi et al., 1987;
Marron et al., 1988;
Onuma & Hui, 1988;
Brayman & Miller, 1989;
Cossarizza et al., 1989a, 1989b;
De Loecker et al., 1989;
Goodman et al., 1989;
Rodemann et al., 1989;
Brayman & Miller, 1990;
Lerchl et al., 1990;
Omote et al., 1990;
Greene et al., 1991;
Liboff et al., 1991_Guy, 1987;
Chen & Ghandi, 1989;
Brown & Chattpadhyay, 1991;
Devyatkov et al., 1991__Adey & Lawrence, 1984;
Blank & Findl, 1987;
Ramel & Norden, 1991;
Grundler et al., in press__
Endogenous EM fields, including biophotons__Mathew & Rumar, in press_Mathew & Rumar, in press_Popp et al., 1984;
Chwirot et al., 1987;
Popp et al., 1988_Wijk & Schamhart, 1988;
Popp et al., 1992__
Note: Reports listed in table 2 are selected from refereed medical and scientific journals, multiauthor monographs, conference proceedings, and patents. See References for identification of sources. This is a representative selection from a large body of relevant sources and is not meant to be exhaustive or definitive.
A more detailed introduction to the field of BEM and an overview of research progress is available in the following monographs and conference proceedings: Adey, 1992; Adey and Lawrence, 1984; Becker and Marino, 1982; Blank, 1993; Blank and Findl, 1987; Brighton and Pollack, 1991; Brighton et al., 1979; Liboff and Rinaldi, 1974; Marino, 1988; O’Connor et al., 1990; O’Connor and Lovely, 1988; Popp et al., 1992; and Ramel and Norden, 1991.
Gauss is a unit of magnetic flux density. For comparison, a typical magnet used to hold papers vertically on a refrigerator is 200 G.
Pulsed Electromagnetic Field Therapy, PEMT. How does it work?
Lecture abstract Dr. D. Laycock, Ph.D. Med. Eng. MBES, MIPEM, B.Ed.
All living cells within the body possess potentials between the inner and outer membrane of the cell, which, under normal healthy circumstances, are fixed. Different cells, e.g. Muscle cells and Nerve cells, have different potentials of about -70 mV respectively. When cells are damaged, these potentials change such that the balance across the membrane changes, causing the attraction of positive sodium ions into the cell and negative trace elements and proteins out of the cell. The net result is that liquid is attracted into the interstitial area and swelling or oedema ensues. The application of pulsed magnetic fields has, through research findings, been shown to help the body to restore normal potentials at an accelerated rate, thus aiding the healing of most wounds and reducing swelling faster. The most effective frequencies found by researchers so far, are very low frequency pulses of a 50Hz base. These, if gradually increased to 25 pulses per second for time periods of 600 seconds (10 minutes), condition the damaged tissue to aid the natural healing process.
Pain reduction is another area in which pulsed electromagnetic therapy has been shown to be very effective. Pain signals are transmitted along nerve cells to pre-synaptic terminals. At these terminals, channels in the cell alter due to a movement of ions. The membrane potential changes, causing the release of a chemical transmitter from a synaptic vesicle contained within the membrane. The pain signal is chemically transferred across the synaptic gap to chemical receptors on the post-synaptic nerve cell. This all happens in about 1/2000th of a second, as the synaptic gap is only 20 to 50 nm wide. As the pain signal, in chemical form, approaches the post-synaptic cell, the membrane changes and the signal is transferred. If we look at the voltages across the synaptic membrane then, under no pain conditions, the level is about -70 mV. When the pain signal approaches, the membrane potential increases to approximately +30 mV, allowing a sodium flow. This in turn triggers the synaptic vesicle to release the chemical transmitter and so transfer the pain signal across the synaptic gap or cleft. After the transmission, the voltage reduces back to its normal quiescent level until the next pain signal arrives.
The application of pulsed magnetism to painful sites causes the membrane to be lowered to a hyper-polarization level of about -90 mV. When a pain signal is detected, the voltage must now be raised to a relatively higher level in order to fire the synaptic vesicles. Since the average change of potential required to reach the trigger voltage of nearly +30 mV is +100 mV, the required change is too great and only +10 mV is attained. This voltage is generally too low to cause the synaptic vesicle to release the chemical transmitter and hence the pain signal is blocked. The most effective frequencies that have been observed from research in order to cause the above changes to membrane potentials, are a base frequency of around 100Hz and pulse rate settings of between 5 and 25Hz.
Pulsed magnetic field therapy and the physiotherapist
Dr. D. C. Laycock, Ph.D. Med. Eng. Westville Consultants
The therapeutic effect of the application of pulsed magnetic field therapy (PMFT) has at last received world-wide recognition, although for a long time many practitioners saw it only as an aid to fracture union. Research has now shown that it has the potential to improve a wide range of conditions, although few understood just how it achieved its effectiveness. Extensive research has since been carried out to determine the mechanism by which this occurs. For the physiotherapist, presented with a wide range of clinical problems, PMFT is an invaluable aid to the clinic.
Resolution of soft tissue injuries:
Over the past few years, research has shown that its effectiveness is not through heat production – as is the case with some modern treatments – but is at the cellular level. One significant outcome of this is the effect it has on soft tissue injuries. As early as 1940 it was suggested that magnetic fields might influence membrane permeability. It has since been established that magnetic fields can influence ATP (Adenosine Tri-phosphate) production; increase the supply of oxygen and nutrients via the vascular system; improve the removal of waste via the lymphatic system; and help to re-balance the distribution of ions across the cell membrane. Healthy cells in tissue have a membrane potential difference between the inner and outer membrane. This causes a steady flow of ions through its pores. In a damaged cell the potential is raised and an increased and an increased sodium inflow occurs. As a result, interstitial fluid is attracted to the area, resulting in swelling and oedema.
The application of PMFT to damaged cells accelerates the re-establishment of normal potentials (Sansaverino) increasing the rate of healing and reducing swelling. This can help to disperse bruising also. A magnetic field pulsed at 5Hz with a base frequency of 50Hz can have the same effect as an ice pack in that in that it causes vasoconstriction.
Effects on fracture repair:
Acceptance of magnetic fields in medicine came about foremost in the field of orthopedics. Low frequency and low intensity fields have been used extensively for the treatment of non-union fractures. By 1979 this method was approved in the USA as a safe and effective treatment for non-union fractures; for failed arthroses; and for congenital pseudo-arthroses. According to Bassett this method has been used by more than 6,000 surgeons. The success rate was over 80% for tibial lesions. No patient suffered complications and biological side-effects included improved healing and increased neural function. In-depth research carried out to investigate this, shows that magnetic fields influence the process of bone formation in the intercellular medium. Madronero showed that bone healing was promoted by means of the influence of the magnetic field on the crystal formation of calcium salts.
Pulsed magnetic field therapy has been shown to bring about a reduction of pain, which again is due to action at the cellular level. Pain is transmitted as an electric signal, which encounters gaps at intervals along its path. The signal is transferred in the form of a chemical signal across the synaptic gap and this is detected by receptors on the post-synaptic membrane. A charge of about -70mV exists across the inner and outer membranes, but when a pain signal arrives it raises this to +30mV. This action causes channels to open in the membrane, triggering the release of a chemical transmitter and allowing ions to flow into the synaptic gap. The cell then re-polarizes to its previous resting level. Research by Warnke suggests that PMFT affects the quiescent potential of the membrane, lowering it to a hyper-polarized level of -90mV. Transmission is effectively blocked since the pain signal is unable to raise the potential to the level required to trigger the release of the chemical transmitter. Again, the frequency of the applied magnetic field is important, as the most effective frequency to produce this effect was found to be a base frequency of 100Hz pulsed at between 5 and 25 pulses per second.
The value of pulsed magnetic field therapy has been shown to cover a wide range of conditions, with well documented trials carried out by hospitals, rheumatologists and physiotherapists. For example, the department of rheumatology at Addenbrookes Hospital carried out investigations into the use of PMFT for the treatment of persistent rotator cuff tendinitis. The treatment was applied to patients who had symptoms refractory to steroid injection and other conventional treatments. At the end of the trial, 65% of these were symptom free, with 18% of the remainder being greatly improved.
Lau (School of Medicine, Loma University, USA) reported on the application of PMFT to the problems of diabetic retinopathy. Patients were treated over a 6-week period, 76% of the patients had a reduction in the level of numbness and tingling. All patients had a reduction of pain, with 66% reporting that they were totally pain-free. Many research studies, including Lau, reported on the application of PMFT for conditions such as sports injuries and for patients with joint and spinal problems. Although these are too numerous to mention individually, in almost every instance there was a reduction, if not complete resolution of symptoms. Soft tissue injuries and joint pains tended to be resolved within 5 days of treatment. Patients with cervical problems and low back pain were also successfully treated, whereas previous treatment with ice, traction and other therapies had been unsuccessful. In yet another trial, the effect of applying PMFT to sufferers of Multiple Sclerosis was investigated (Geseo) 70% of sufferers had a reduction of weakness, pain and spasticity, with 50% reporting improvement of their bladder incontinence. Through the evaluation of hundreds of research papers, a number of points have been established regarding PMFT: The field must be pulsed, with low frequency to achieve the best effect.
Different conditions require different frequencies. For example, 5Hz causes vasoconstriction whilst 10Hz and above causes vasodilatation. Biological effectiveness is achieved in just 10 minutes for most injuries, so that long treatment sessions are not required. When used at the correct level there are no recorded side effects. Although PMFT is not yet recommended for use during pregnancy or in the presence of tumors, there are papers to suggest that magnetic fields can inhibit the growth of tumors.
Modification of biological behavior of cells by Pulsing Electromagnetic fields, (PMFT)
Ben Philipson, Curatronic Ltd.
On the major part of the calcified mass of adult bone there are no changes in bone mass, however there is a part on which bone is being formed and a part on which bone is being resorbed. Decalcification occurs when bone resorption is greater than bone formation. Bone formation comprises two steps, the laying down of the extra-cellular matrix and the deposition therein of bone salts. The dynamic processes of formation and destruction of bone are under cellular control. Bone formation is controlled by single nuclear cells called Osteoblasts, and bone resorption by multinuclear giant cells are called Osteoclasts. Bone is a specialized connective tissue, in which a matrix consisting of collagen fibers and a large variety of other proteins and ground substance are impregnated with a solid mineral. The bone matrix is responsible for the resistance of bone to tractional and torsional forces. The collagen forms more than 25 % of the bones and is synthesized by osteoblasts. On the bone surface collagen fibers are normally arranged in concentric rings of hard calcified matrix.
The bone minerals provide to the bone compressive strength and rigidity. It contains the mineral salts hydroxyapatite and calcium. In addition there are small amounts of magnesium hydroxide, fluoride and sulphate. As these salts are deposited in the framework formed by the collagen fibers of the matrix, crystallization occurs and the tissue hardens. This process is called calcification or mineralisation. Both the concentrations of ions of calcium and phosphate in the extracellular fluid maintain crystallization. If the concentration is not adequate the tissue will not be hard enough resulting in increased bone fracture risk.
There are two types of bone structure. Cortical (compact) bone and trabecular (spongy) bone. Cortical bone is more dense and constitutes of 80 % of the skeletal mass and forms the external layer of all bones in the human body. Trabecular bone consists of lamellae arranged in an irregular latticework of thin plates of bone and helps long bones to resist the stress of weight placed on them.
The process by which bone forms is called ossification. Bone forms either by the mineralisation of cartilage or directly by osteoblasts in a collagenous matrix. During the first two decades of life bone grows, followed by consolidation and reaching its peak value around thirty five years. After this peak, bone loss starts. Nutritional factors, especially calcium intake, the level of physical activity and generic factors are important in determining the peak bone mass.
When a bone is fractured, it heals with bone. Bone is the only solid tissue in the body that can replace itself. Bone healing is simple when it occurs smoothly, complicated when it does not. The process is being initiated by stimuli from the bone itself. Fractures through bone with a good blood supply, surrounded by muscle and without soft tissue trauma, have an excellent chance of healing, but fractures at the middle of long bones, particularly with extensive soft tissue damage, have a high incidence of non-union.
Selected low-energy time-varying electromagnetic fields have been used during the past 15 years to treat un-united fractures (non-unions). More than 100,000 patients, mainly in the USA, have been treated. Retrospective studies have substantiated their biological effectiveness in large numbers. Bone is responsive to the mechanical demands placed on it. When loading diminishes, as it does during bed rest, immobilization and weightlessness, bone mass is lost. On the other hand when loading is increased correctly, bone mass increases.
Results of bio-mechanical and histologic investigations prove that electromagnetic fields not only prevent bone loss, but also restores bone mass, once lost. A program was set up at McGill University of Montreal, where was found that electromagnetic fields damp bone resorption activity. Furthermore prove was found that selected electromagnetic fields increase bone formation.
The resorption of bone is lowest and formation of new bone greatest, when energy of the imposed fields is concentrated in the lower frequency components. These results are consistent with other studies showing, that cells respond to a broad spectrum of frequencies. They appear to be most sensitive to frequencies in the range of those produced endogenously, that is in the range of 100 Hz or less.
Tissue dosimetry studies show that the frequency response of cortical bone over a range of 100 Hz to 20 kHz show a steep roll off between 100 and 200 Hz.
Electromagnetic fields at specific frequencies have shown to produce osteogenic effects in a turkey ulna model. Furthermore low-amplitude signals decrease bone resorption in a canine fibular model. Lifestyle factors like malnutrition, smoking, excessive use of alcohol and a sedentary lifestyle contribute to, and worsen, osteoporosis. It is not known whether this response derives from decreased osteoblastic activity, increased osteoclastic resorption, or both. Elderly persons can heal fractures in normal intervals, showing that osteoblasts can be activated by appropriate stimuli.
A study at the University of Hawaii School of Medicine was designed to provide concrete data on the restoration of bone mass in post-menopausal females. A total of 20 subjects between 57 and 75 years, all with decreased bone mineral density as defined by a bone densitometer, were treated during a period of 12 weeks. After a period of 6 weeks the bone density rose in those patients with an average of 5.6%.
Electromagnetic fields do modify biological behavior by inducing electrical changes around and within the cell. The key to rational use of electromagnetic fields lies in the ability to define the specific treatment parameters (amplitude, frequency, orientation and timing). Properly applied pulsed electromagnetic fields, if scaled for whole body use, has clear clinical benefits in the treatment of bone diseases and related pain, often caused by micro-fractures in vertebrae. In addition, joint pain caused by worn out cartilage layers can be treated successfully, through electromagnetic stimulation, increasing the partial oxygen pressure and resulting in increased calcium transport. Repair and growth of cartilage is thus stimulated, preventing grinding of the bones.