Transcutaneous Bioelectric Stimulation - the Problem of Penetration and Propagation

Chelan, WA, March 17, 2007 --( In the past few years, there has been a resurgence of interest in bio-electrical therapies in the medical community. In some areas however, there has been a proliferation of research resulting in numerous clinical applications directed at patient care. Many health care facilities are successfully offering various forms of treatment based on electromagnetic healing principles. These therapies utilize implanted electrodes in various parts of the patient’s body.

The surgical implantation of foreign bodies with lead wires exiting through the skin, expose patients to all the attendant risks of surgery, anesthesia, and infection. In addition the financial costs to the patient make these procedures available only to those who can afford them. Nor do surgically implanted electrodes circumvent propagation problems existing in the electrical path between the electrodes.

The propagation of electrical current through organic tissues is not easily accomplished. Even if at first glance this appears to be a non issue, in reality and practically organic tissue penetration is a major difficulty. Most of the time, the approach to this problem reflects “direct current” thinking, even though the current is pulsed. With this type of thinking it is believed that the problem area must be located within the electrical path, in straight line, between the two electrodes. In reality, the main obstacle to electrical stimulation is not the DC electrical resistance presented by the tissues; it is the impedance or resistance to AC current which is the problem. Generally, the application of pulsed DC current to biological tissues does not provide the results expected, with a few exceptions, due to the impedance of the organic cells. The solution consisting in increasing the current to force a passage through the tissues, only results in the dissociation of the blood into hydrogen and oxygen bubbles which permeate the organic tissues and blood vessels. To obviate this effect the apparent reasonable solution would be to stop the stimulation for a period of time and let the bubbles of gases dissipate, and then resume the stimulation. Designing a stimulator without taking this into account can only lead to ineffective results or even potentially dangerous outcomes such as the dissociation of blood described above There is however another solution.

At this juncture it is important to notice that most neophytes express electrical information in terms of “volts”. This association is incorrect since the “work” is performed by the “current” which is effectively the charge carrier. In fact the difference of potential (voltage) is only an artifact resulting from the passage of the current through a medium. Therefore electrical pulsing for the purpose of bioelectric applications must be expressed in terms of Ampères or Coulombs but not in Volts.

Generally in organic tissues the current levels, as emitted by the brain, are extremely small. Therefore the currents generated to stimulate cellular tissues must be adjusted to be similar in magnitude as those found in nature. Most effective therapies require pulsed DC stimulation, at very low current levels, and relatively high frequencies. Besides reducing the current, several problems affect the propagation when dealing with pulsed micro-currents. One of them is the “skin interface barrier”. As pulsed micro-currents propagate, depending on their frequency, they are rapidly attenuated by impedance of the tissues (resistance to AC current). To circumvent this problem, the only viable options are to characterize the skin interface and apply a correction factor to the stimulation. It is important to understand that this problem exists regardless of the placement of the electrodes. It does not matter whether they are implanted or attached to the surface of the skin for transcutaneous stimulation.

Technical Applications Inc. has found a way to circumvent the effects of the skin barrier interface. Using a microprocessor and techniques developed in the analysis of RADAR echo returns in aviation, we have been able to greatly decrease the attenuation of the stimulation signals. This discovery results in the ability to propagate very small signals without having to “force” the current through the skin interface. In other words, Technical Applications has broken the skin barrier, without negative side effects, and with all the benefits of direct stimulation of the cells in the tissues.

Technical AP
Jeff Monray