A disadvantage is the tinkering required for the average pain patient to find the best combination of variables for effective relief. Even after repeated attempts at different parameter combinations, TENS devices may not alter pain results. Although effective to some extent, they are simply an application of force, a counter-irritant produced analgesia. They provide no significant residual effect and as with drugs, tolerance is a significant problem.

Becker and Nordenström have provided a rational basis for a new and vastly more effective form of electromedical intervention for which Joseph M. Mercola, D.O. and Daniel L. Kirsch, Ph.D. (1994) coined the term "microcurrent electrical therapy" (MET). A growing body of research shows the effectiveness of MET to accelerate, and even induce healing.

Eaglstein and Mertz (1978) have shown moist wounds to resurface up to 40% faster than air-exposed wounds. Falanga (1988) found that certain type of occlusive dressings, like Duoderm, accelerate the healing of wounds. It is probable that these dressings achieve their effects by promoting a moist environment (Kulig, Jarski, & Drewek, 1991). When a wound is dry, its current flow is shut off. The moisture may allow the endogenously produced current of injury to flow and promote wound healing. Electrical stimulation of the wound also tends to increase the amount of growth factor receptors which increases the amount of collagen formation (Falanga, 1987).

Electricity was first used to treat surface wounds over 300 years ago with charged gold leaf to prevent smallpox scars (Robinson, 1925). There are several recent studies supporting the beneficial effects of treating wounds with an artificial current of injury (Goldin, 1981; Jeran, 1987; Ieran, 1990; Mulder, 1991). Experimental animal wound models in the 1960's demonstrated that electrical intervention can result in accelerated healing with skin wounds resurfacing faster, and with stronger scar tissue formation (Carey & Lepley, 1962; Assimacopoulos, 1968).

Assimacopoulos (1968) published the first human study using direct electrical current for healing. He documented complete healing of chronic venous stasis leg ulcers in three patients with six weeks of electrical therapy. One year later the most frequently cited work in the history of electrical wound healing was published by Wolcott and Wheeler (1969). They used direct currents of 200-1,000 microamperes for 67 patients. Gault and Gatesn (1976) repeated the Wolcott and Wheeler protocol for 76 additional patients with 106 ischemic skin ulcers. Carey and Wainapel (1985) performed one of the only studies on this subject published with equal and randomized control and study groups. All of these studies documented significant accelerated healing with electrical stimulation.

Working with Wolcott and others, Rowley et al. (1974) updated their initial experience with another group of patients having 250 ischemic ulcers of various types. These included 14 symmetrical control ulcers. The stimulated ulcers had a fourfold acceleration in healing response compared to the controls.

One additional consistent observation in these studies was that there was a reversal of contamination in the wounds. Wounds that were initially contaminated with Pseudomonas and/or Proteus were usually sterile after several days of MET. Other investigators have also noticed similar improvements and encourage the use of this therapy as the preferred treatment for indolent ulcers (Kaada, Flatheim, & Woie, 1991; Barron, Jacobson, 1985; Lundeberg, Eriksson, & Malm, 1992; Alvarez et al., 1983). Additionally, no significant adverse effects resulting from electrotherapy have been documented (Weiss, 1990). A review of the literature by Dayton and Palladino (1989) shows that microcurrent electrical therapy is clearly an effective and safe supplement to the non-surgical management of recalcitrant leg ulcers.

Some of these studies used unipolar currents that were alternated between negative and positive based on various criteria. Some researchers initially used negative current to inhibit bacterial growth and then switched to positive current to promote healing. To date no study has compared this variable of MET. However, there is some compelling basic science research, and one animal study suggesting that a bipolar current, which provides both negative and positive phases, may be better for wound healing (Stromberg, 1988; Windsor, Lester, & Herring, 1993).

As mentioned previously, in the 1960s Dr. Becker demonstrated that an electrical current is the trigger that stimulates healing, growth and regeneration in all living organisms. He found that repair occurs after an injury in response to signals that come from an electrical control system and suggested that this system became less efficient with time.

Dr. Becker (1985) developed his theory of biological control systems based on concepts derived from physics, electronics, and biology. He postulated that the first living organisms must have been capable of self-repair, otherwise they never would have survived. The self-repair process requires a closed-loop system. A specific signal is generated which causes another signal to start repair. The injury signal gradually decreases over time with the repair process until it finally stops when the repair is complete. Such a primitive system does not require demonstrable consciousness or intelligence. Therefore, many animals actually have a greater capacity for self-healing than do humans.

Science has amassed a vast amount of information on how the brain and nervous system work. Most of this research involves the action potential as the sole mechanism of the nerve impulse. This is a very sophisticated and complex system for the transfer of information. It is helpful to compare this currently accepted process of the nervous system to a computer.

The fundamental signal in both the computer and the nervous system is a digital one. Both systems transfer information represented by the number of pulses per unit of time. Information is also coded according to where the pulses go and whether or not there are more than one channel of pulses feeding into an area. All our senses (e.g., smell, taste, hearing, sight and touch) are based on this type of pulse system. Like a computer, the nervous system operates remarkably fast and can transfer large amounts of information as digital "on and off" data.

It is unlikely that the first living organisms had such a sophisticated system. Becker believes they must have had a much simpler mechanism for communicating information because they did not need to transmit large amounts of sophisticated data. Accordingly, they probably used a much simpler analog system. An analog system works by means of simple DC currents. Information in an analog system is represented by the strength of the current, its direction of flow, and slow wavelength variations in its strength. This is a much slower system when compared to the digital model. However, the analog system is extremely precise and works well for its intended purpose.

Becker theorizes that the first living organisms used this analog type of data-transmission and control system for injury repair. He postulates that we still have this primitive nervous system in the perineural cells of the central nervous system. These cells comprise 90% of the nervous system. The perineural cells have semiconductor properties that allow them to produce and transmit non-propagating DC signals.

This analog system senses injury and controls repair. It controls the activity of cells by producing specific DC electrical environments in their vicinity. It also appears to be the primary primitive system in the brain, controlling the actions of the neurons in their generation and receipt of nerve impulses. This allows it to regulate our consciousness and decision-making processes. Given this understanding, the application of the correct form of electrical intervention is a powerful tool for treating pain, initiating the endogenous mechanisms of self-repair, and altering states of consciousness.

Clinically, we can use a point finder (ohmmeter) to measure pathological tissue because it exhibits a reduction in conductivity. This seems to be true in every case except in inflammatory conditions where the hot fluids conduct extracellularly causing a false-positive readings. The less conductive tissue sets up an electrical difference, or potential, on either side of the injury that controls pain and signals the healing process. This is known as the current of injury (COI).

Since some tissues conduct electricity better than others, it is possible to calibrate a measurement device to an area near the injury before treating. Once a low conductive area is found, a microampere current with an effective waveform can augment the current of injury to effectively control pain as well as initiate or increase the rate of healing. Lerner and Kirsch (1981) developed this system and called it bioconductive therapy. The same meter can read a post treatment response (PTR) measurement. Generally up to four, six to ten second applications of stimulation with two small diameter probes is adequate per electrode placement. Several varying placements in an area may be needed to obtain an improved PTR. Once the area is adequately treated the PTR will exhibit a higher value with a slower decay time (Ullis, 1983). When using an effective device the improved PTR will almost always be associated with the patient's subjective feeling of improvement.

The devices used for bioconductive therapy have come to be known as microcurrent stimulators. They deliver a much weaker signal about 2,500 times longer per pulse than TENS. The full spectrum ("shotgun") of frequencies within each pulse at this wavelength provide a phenomenally effective therapy. It is believed that cells within a specific organ or tissue system communicate through specific frequencies in the microampere range. The right frequency activates the COI causing the system to tend towards homeostasis. Caution is advised against purchasing devices claiming to be "cybernetic", or able to measure and automatically deliver the correct frequency for a given patient. Although at least one manufacturer makes such a claim, there is no such technology or scientific support material to design such a thing at this time.

Originally, bioconductive therapy devices were large, expensive, metered units designed for clinical use only. A good microcurrent device requires more than ten times the circuitry of a standard TENS. However, in 1982, what is now Electromedical Products International, Inc. (EPII) of Mineral Wells, Texas introduced the first homecare microcurrent stimulator to the market. Their product, called the Alpha-Stim 350 weighed six pounds and was about half the size of a shoe box. Using surface mount technology manufactured by robotics EPII has been able to manufacture scaled down versions since 1990 at a cost competitive with TENS. Since then a number of imitations have flooded the market, primarily from Taiwan. Most of these products do not produce reproducible results because the design engineers know nothing about the underlying electrophysiology and they use cheap parts with tolerances as high as 35%. Alpha-Stim technology is actually produced by using two waveforms for each channel to create a full bioelectrical frequency range and introduce random factors into the waveform preventing the nervous system from recognizing it, and therefore habituating to it.

The biggest mistake practitioners make with microcurrent devices is to use them the same way they would use a TENS device. As an example, TENS is often applied on either side of and close to the spine for back pain. This will not work with microcurrent technology because the current, following the path of least resistance, is too weak to actually reach the spine.

It is extremely important to take a comprehensive history before beginning MET. One should determine when the pain first presented, its frequency, duration, intensity, limitations-of-motion, positions which exacerbate the pain and any precipitating factors. Ask about the specifics of previous treatments. Microcurrent electrical therapy is a very