Physical Characteristics and Physiological Effects of High Frequency Currents

Abstract

FOR many years medicine has been an art, but in recent years the influence of physics and chemistry has been so effective that it has assumed more and more the character of a systematic and accurate science; as the result of this the corollaries and methods of the natural sciences should be directly applicable without further discussion and proof. It should thus be permissible to state definitely that all future progress in the application of high frequency currents must depend on further careful coordination of the physical characteristics of the currents and of the biological or physiological effects produced by their application. Introduction That clinical results should be carefully classified and tabulated according to some definite plan and principle is, of course, not a new proposition, but at the present day such a classification should be made on the basis of definite and accurately reproducible physical characteristics of the agent. In the case of high frequency currents we encounter as the first obstacle an antiquated and nondescript terminology which is not understood by modern physicists and engineers and which does not even define and characterize carefully the types and kinds of currents applied as the agents of which the effects are supposed to be investigated and tabulated. A further obstacle in the solution of this problem consists in the use, by electrotherapists, of high frequency apparatus built empirically, with no particular, definitely stated or indicated purpose; with hardly any exception, the electrical constants and characteristics of high frequency apparatus employed to-day in medicine are generally unknown. The general lack of confidence in this interesting agent in medicine and the many attacks upon it are, therefore, explainable as being due entirely to lack of reliable data and experimental facts. With this condition in mind, the writer has undertaken to establish certain connections between physical characteristics and physiological effects of high frequency currents, believing, with Thomas Benton Elliot, that “Medicine owes no debt of gratitude to those who teach to her theories without proof.” The Problem In a broad sense, there are distinct effects recognized for each of the three fundamental types of current employed in electrotherapy. The direct current, generally designated as galvanic current, is known for its effects of endosmosis and electrolysis through the basic work of physical chemists and physiologists such as Perrin, Freundlich, Martin Fisher and many others. The interrupted or asymmetric alternating types of current of less than 500 impulses frequency, called Faradic current, are known to produce definite effects upon the musculature, and the many works on electro-physiology give full information as to the effects and action of these currents upon the muscular system.