Microcurrent Electrical Therapy (MET): A Tutorial
The last three decades have seen a rise in the use of microcurrent electrical therapy (MET). It is used primarily by physicians, dentists, veterinarians, occupational therapists, psychologists, chiropractors, and acupuncturists for the management of acute, chronic, and post-operative pain. The use of MET is often accompanied by the promotion or acceleration of healing. Table 1 provides a sample listing of the indications and contraindications for MET.1
It should be emphasized that with previous forms of electrotherapy (e.g., transcutaneous electrical nerve stimulators and other technologies based on using electric force as a counter-irritant), price often was the deciding factor when making purchase decisions among the many units offered. In choosing a microcurrent device, the most critical aspect is the waveform. Specific waveform attributes are essential to achieving good results. One must determine if there is legitimate research associated with a given technology before purchasing or prescribing. Some of the Asian manufacturers, for example, have simply reduced the current from their TENS devices and started to sell them as “microcurrent” devices. The Food and Drug Administration is not helpful in this instance as the FDA will readily accept devices being sold for pain indications as TENS. Accordingly, it is caveat emptor and each practitioner must do their own due diligence on the best technology and protocol.
The class of devices known as microcurrent have current levels less than one milliampere. However, that is only one aspect of the waveform. Just as not all 5 mg pills are alike, neither are 0.5 Hz MET devices. Heffernan compared a commercially available MET device using a variable maximum frequency of 0.5 Hz (0 to 2 second pulses) in a complex 10 second bipolar waveform with a control device built by the researcher delivering a simple repetitive 0.5 Hz bipolar waveform.2 Using the same electrode locations (bilaterally on the wrists) and the same amount of current (500 microamperes), he found that the MET device was able to significantly reduce pain and produce beneficial smoothing on electroencephalographic analysis in patients with chronic degenerative joint disease that were unresponsive to medication. The 0.5 Hz control device did not produce a significant reduction in pain and only produced an undesirable sinusoidal pattern on the EEG.
Fortunately, MET devices are often subsensory so that they lend themselves to the gold standard of double-blind studies in a manner similar to pharmaceutical research. There is no excuse for a medical device company—entrusted with patient care on the order of a licensed practitioner — not to sponsor or encourage research with its proprietary technology.
Arndt’s Law is often cited in discussions of MET. It states that weak stimuli excite physiological activity, moderate stimuli favors it, strong stimuli retards it, and very strong stimuli arrests it.3 Chang found that 500 microamperes caused adenosine triphosphate (ATP) to increase by 500% while raising the current over 5 milliamperes caused ATP to drop below baseline norms. Further, at 100-500 microamperes, amino acid transport rose 30-40% above controls.4
An effective MET waveform will use resonant frequencies that activate central pain modulatory mechanisms. Cells throughout the body manufacture peptides that act as ligands to surface receptors on other remote cells, communicating throughout the body via the extracellular fluid and the circulatory system.5 Nordenström has proposed a model of biologically-closed electric circuits analogous to closed circuits in electronic technology.6,7 His premise is that mechanical blood circulation is closely integrated anatomically and physiologically with a controlling bioelectrical system. Endogenous biological circuits are affected by normal electrical activities of the body and pathological changes. Nordenström views bioelectricity as the primary catalyst of the healing process and has shown that augmenting it with MET can produce profound therapeutic effects.
MET treatment with an effective waveform may act similar to ligands in activating receptors to send their messages into cells and produce effects similar to a wide range of chemical messengers. The protocols presented herein effect the peripheral pain site directly and access the central nervous system by placing electrodes in position to direct the current through the spine.
MET: A Tutorial
While MET devices differ, and the manufacturers’ recommendations should always be followed when first learning to use a medical device, a basic protocol can be utilized for quick and consistent results. This article is based on the author’s 33 years of experience with MET. It is not meant as a complete discourse on the subject, but rather a “how-to” tutorial to achieve substantial, cumulative effects in the least amount of time. MET is a very easy and efficacious procedure when performed properly. As with any medical intervention, there is a learning curve so don’t give up if the first few treatments do not produce the desired outcomes. MET produces significant results (>25% pain relief) for over 90% of patients.8
MET is both long lasting and cumulative. The goal of a MET session is to achieve 100% pain relief. Although not achievable in every case, and seen less often with the first few treatments in a series, anything less than full pain relief in a treatment session will inversely impact the longevity of the results obtained and impact the cumulative effect. The protocols presented here will usually take 2-5 minutes, but may take up to 15 minutes in patients who have severe or multiple pathologies. Stop when the pain is no longer able to be elucidated, even in a position that previously exacerbated the pain. Of course, one can always cause pain in extreme positions so it is only reasonable to evaluate the treatment in comparison within the limits of the restricted limitation of motion that the patient originally presented with and never more than the normal range of motion.
Results will vary with the technology utilized, the pathology of the patient undergoing treatment, the overall health, hydration, and compliance of the patient. The patient’s history, especially as it pertains to prior medical intervention, may be a defining factor. It is not possible to achieve results when limiting treatment with MET to the chief complaint since the entire body is an electrical circuit.6,7 Previous injuries and surgical scars may need to be treated due to their highly-resistive nature that cause subtle electrical blocks. If a patient is refractory to treatment with MET, place electrodes at the end of each scar or cover small scars with an electrode (with the other one being placed opposite the scar or on another scar), for at least 10 minutes, 4 days in a row. A successful scar treatment may exacerbate pain as it increases overall functioning and stamina. If the pain increases, the protocols that are the subject of this article will usually start to work. In rare, difficult cases, it could take 3 weeks or more of daily treatment to produce a significant cumulative effect. This is especially true in treating patients with fibromyalgia.