Effects of exposure to electromagnetic fields emitted by GSM 900 and WCDMA mobile phones on cognitive function in young male subjects

Abstract

Results of studies on the possible effects of electromagnetic fields emitted by mobile phones on cognitive functions are contradictory, therefore, possible effects of long-term (7 h 15 min) electromagnetic field (EMF) exposure to handset-like signals of Global System for Mobile Communications (GSM) 900 and Wideband Code-Division Multiple Access (WCDMA) on attention and working memory were studied. The sample comprised 30 healthy male subjects (mean ± SD: 25.3 ± 2.6 years), who were tested on nine study days in which they were exposed to three exposure conditions (sham, GSM 900 and WCDMA) in a randomly assigned and balanced order. All tests were presented twice (morning and afternoon) on each study day within a fixed timeframe. Univariate comparisons revealed significant changes when subjects were exposed to GSM 900 compared to sham, only in the vigilance test. In the WCDMA exposure condition, one parameter in the vigilance and one in the test on divided attention were altered compared to sham. Performance in the selective attention test and the n-back task was not affected by GSM 900 or WCDMA exposure. Time-of-day effects were evident for the tests on divided and selective attention, as well as for working memory. After correction for multiple testing, only time-of-day effects remained significant in two tests, resulting in faster reactions in the afternoon trials. The results of the present study do not provide any evidence of an EMF effect on human cognition, but they underline the necessity to control for time of day.

Quasi-optical Systems Based on Periodic Structures

“…A important observation must be made here. One of the two equations removed is not consistent with the others in (61). This equation is the following:…”

“…(59)) B nκ (U κ , U 3κ ) = B nκ (U κ , 0, U 3κ ), n = 1, 3, denote the matrices of the complex-valued non-linear algebraic equations, and U inc κ , C 3κ (U κ ) = C 3κ (U κ , 0) , C κ (0, U κ ) = 0 are the right-hand side vectors. The solution of (75) is obtained by means of successive approximations using the self-consistent approach based on the iterative algorithm (61).…”

“…According to (70), the matrix entries in (69) depend on the dielectric permittivities. The latter are defined by the scattered and generated fields U κ , U 2κ , U 3κ of the problem (49) by means of the algorithm (61). This defines the basic design of the implemented numerical algorithm.…”

“…This defines the basic design of the implemented numerical algorithm. The investigation of the eigen-modes of the linearised non-linear structures (69) should always precede the solution of the non-linear scattering and generation problem in the self-consistent formulation (61). Note that, in the analysis of the linear structures, the problem of excitation (scattering) and the spectral problem can be solved independently.…”

“…For this case we passed from (49) to (75) and from (66) to (69) by the help of Simpson's quadrature rule. The numerical solution of (75) was obtained using the self-consistent iterative algorithm (61). The problem (69) was solved by means of Newton's method.…”