groups he found a longer reaction time at the higher frequency compared to the lower frequency (42).
Persinger et al. found no difference in the mean reaction time in either males or females due to 0.3-30
v/m, 3-10 Hz, but he did find a significant difference between the sexes in the variability of the
response to a given field (43).
As measured by a task consisting of the addition of sets of five two-digit numbers, a 60 Hz, 1-
gauss field altered the ability to concentrate in human subjects (Fig. 5.5) (39). All 6 experimental
subjects demonstrated a decline in performance in the second test session of the exposure period, and
all 6 improved in the first test session of the postexposure period. In contrast, the control subjects
showed no consistent changes.
Fig. 5.5 Average performance of the experimental and control groups on the Wilkinson Adding Task.
The subjects were confined to the test facility throughout the study, and were unaware of the exact
timing of the 24-hour exposure period.
For more than a decade, Ross Adey and his colleagues have sought to understand the molecular
mechanisms that underlie field-induced behavioral changes. In the late 1960's they reported that low-
frequency EMFs altered the timing behavior in humans (41) and monkeys (50). The effects were
frequency-dependent in the 2-12. Hz range, and later results suggested that they increased with dose
(51). In 1973, they reported that cats exposed to 147-MHz EMFs, modulated at 0.5-30 Hz, exhibited
altered EEGs (44). The idea that evolved from these studies and others (53), was that extremely weak
EMFs-I0-5 v/m, as calculated on the basis of the simple spherical model described in chapter 2-could
alter neuronal excitability, and presumably timing behavior and the EEG, if they were in the
physiological frequency range (the EEG). An in vitro system involving calcium binding to brain tissue
was then chosen to study the effect of weak EMFs on ionic movement under a hypothesis that altered
ion-binding and the associated conformational changes constituted the mechanism of the EMF-induced
effects. A complex series of results were then obtained concerning the levels of pre-incubated calcium
that were released into solution: at 147 MHz, there was an increase when the EMF was modulated at 6-
10 Hz, but no increase at 0.5-3 or 25-35 Hz (65 ); with EMFs of 6 and 16 Hz, there was a decrease at
10 and 56 v/m, but not at 5 or 100 v/m (66); there was no change in calcium at 1 Hz or 32 Hz, at either
10 or 56 v/m (66); at 450 MHz, modulated at 16 Hz, there was an increase (67). Some of these results
have been confirmed (71). The salient features of the in vitro studies were: (1) the emphasis on
calcium; (2) the opposite results obtained following low-frequency and high-frequency EMF exposure;
and (3) the existence of frequency and field-strength ranges where the effects were at a maximum.
None of these features were seen in the in vivo studies. Grodsky proposed a cell-membrane model
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