MET vs. Transcutaneous Electrical Nerve Stimulation (TENS)
In comparison with TENS therapy, MET uses 1,000 times less current (10-600µA), delivered at an extremely low frequency of 0.5Hz and a 2,500 times longer pulse width (<2s)1,3,6. MET can produce rapid and significant treatment effects, often within 2-5 minutes of stimulation and can treat even intense pain problems3,5.
Furthermore, MET can produce a relatively long-lasting reduction or elimination of pain lasting several hours or days, often after a single or several treatments1,4,5. Repeated stimulation with MET can produce greater benefits over time (5-7 applications) as the effects of this modality are residual and cumulative in many patients2,3,7,8. Residual effects of TENS therapy are minimal in most patients.
Postulated Mechanisms of MET
Microcurrent stimulation appears to affect cellular physiology and produce its effects by reducing the electrical resistance of the injured tissue and restoring its cellular capacitance1,3. A study by Chen et al.9 further indicates that applications of microcurrent stimulation (< 500mA) can dramatically increase the production of ATP in the tissue by as much as 500% and increase amino acid transport and protein synthesis in the treated area by 30-40%.
The classic works by Björn E. W. Nordenström10 and Robert Becker11 have shown that endogenous bioelectricity, and changes in the polarity of the tissue triggered by illness or injury, may represent the primary catalyst of the healing process. More recently, Zhao et al.12 have shown that minute electrical fields, similar to those detected endogenously, serve as a prime directional cue to direct cell migration during wound healing and manipulation of these endogenous currents may affect wound healing in vivo. It is then plausible to speculate that stimulation with mild electrical currents may not be limited to analgesis effects but may also help restore or enhance the endogenous current flow and consequently facilitate the healing process11,12.
electrical stimulation, especially at low-frequencies, may also
produce some analgesic effects via release of endogenous opioid
Mercola, J. M. and D. L. Kirsch (1995). The basis for microcurrent
electrical therapy in conventional medical practice. Journal
of Advancement in Medicine,