Comment on “proposed test for detection of nonlinear responses in biological preparations exposed to RF energy”

Balzano [2002] proposed a test to measure ‘‘. . . the nonlinear response of biological cells. . .’’ to 0.9 GHz electromagnetic fields. In our view, the proposal obfuscates the meaning of nonlinearity (N) and dulls appreciation of its true significance regarding the biological effects of electromagnetic fields (EMFs). Beginning in the 1950s, experimental evidence and theoretical considerations were advanced indicating that biological transduction of weak EMFs was more or less precluded, based on considerations of kT [Schwan, 1957; Schwan and Sher, 1969; Schwan, 1973; Schwan, 1982]. The argument has remained substantially unaltered despite the rising tide of the empirical evidence. At least two general approaches evolved in opposition to the antitransductionist viewpoint. In one approach, N was invoked, ultimately leading to the concepts of ‘‘windows’’ and ‘‘resonance’’ as devices to explain how weak EMFs could produce biological effects. The basic idea was that the biological response exhibited a power law or periodic dependence on the applied field (Fig. 1). A key point is that although such functions are algebraically nonlinear, they are dynamically linear because they are solutions to linear differential equations. Solutions to linear differential equations follow the law of superposition, and from this property springs the traditional Holy Grail of the experimentalist—reproducibility of data. The second approach was of an entirely different character because it did not address the kT argument, but rather the implicit claim of authority on which it was based. Those open to the possibility of transduction simply ignored the kT argument because, we think, at one level or another, it struck them as absurd that physics could explain biology, considering the conceptual simplicity of the former and the structural and functional complexity of the latter. The focus, in this approach, was on collecting empirical data. Although the dispute has remained unresolved, what may be a solution has appeared [Lorenz, 1963; Abarbanel, 1994, 1996]—the nature of which is illustrated in Figure 2. Assume that a biological response is measured continuously in three different animals and that, upon presentation of an EMF, two of the animals react in opposite directions and the third does not react. Such behavior is not possible in systems governed by linear differential equations, but it is theoretically possible if the system is governed by nonlinear differential equations (Fig. 3). Experimental evidence suggesting that such behavior (‘‘dynamic nonlinearity’’) can explain EMF induced bioeffects is described elsewhere [Marino, 1995; Marino et al., 2000; Marino et al., 2001a; Marino et al., 2001b; Marino et al., 2002].