Sarimov R.M., Binhi V.N.

In our work [1], we reported that compensation of the geomagnetic field to a level less than 0.4 μT («zero magnetic field», or ZMF) affected human cognitive processes. The compensation of the geomagnetic field was organized in a special wood box of 1×1×1.5 m3 in size. The box included a wire mesh that shielded a person from the outer randomly variable electrostatic field. A similar wire mesh inside the box generated a controllable electrostatic field that modeled the outer field in magnitude but was constant in time and direction. Magnetic field inside the box was measured near the human head to supply a feedback. This allowed the active system of magnetic exposure to compensate the outer magnetic field together with its variations caused by the city electric vehicles and industrial pulses. Forty tested persons who all have given their informed agreement to take part in the experiment were tested for the perfection of their cognitive processes. Each person has been tested twice: in ZMF and, for comparison, in sham conditions. The second session was organized usually in 30-50 days after the first one. Measured were the parameters (task processing times and the number of errors) of the following tests: (i) the rate of a simple motor reflex, (ii) colored words recognition, (iii) short-term color memory, and (iv) recognition of rotated letters. There were eight measurable parameters altogether. Under ZMF, the number of errors was grown and the task processing times were increased by about 2%, in average. This conclusion was made after the measured values were statistically treated using MANOVA. However, individual effects that deviated from the mean by more than «three sigma» have been found in the array of magnetic effects calculated from the measured parameters. At that, practically all of them had the same sign as the observable mean effect. It was unclear in what extent could these readings change the main result of the work, the statement that ZMF affects the parameters of the persons - cognitive processes in average - Therefore, in the present work, methods of multivariate statistical analysis other than MANOVA have been used to study individual human sensitivity to zero magnetic fields. Using the discriminant analysis and the factor analysis, indices of the individual sensitivity of 40 persons have been defined and calculated. Previously reported findings that women and elderly people are more sensitive to ZMF have been confirmed. Temperature and pressure did not influence significantly on the effects of ZMF. At the same time, the effects of ZMF depended on how persons felt and on their allergic status. It has been shown, that non-allergic persons who felt «excellent» executed tests better when those who had occasional allergic reactions and/or felt just «well» or «moderately well». Based on the individual sensitivity indices, different distributions of the magnetic effects over persons have been calculated. Then, the group of persons particularly sensitive to ZMF and that of persons showing no such sensitivity were separated. In the group of sensitive persons, the average magnetic effects reached 9%, and the number of errors in letter recognition reached 28%. The known syndrome of electromagnetic hypersensitivity (EHS) is discussed with regard to these findings.