vices). 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.1

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

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 lowlevel 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.

5. Electroacupuncture.

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.

Research Base

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.

Bone Repair

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).2 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, atten

tion 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 doubleblind 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).