Influence of a 1,800 MHz electromagnetic field on the EEG energy

The present study investigated the influence of electromagnetic fields (EMF), similar to that emitted by mobile phones, on brain activity. Ten women and ten men, matched for age and educational level, performed a short memory task (Wechsler test), with simultaneous Electroencephalogram (EEG) recordings at 15 scalp electrodes, both without (baseline) and with exposure to an 1,800 MHz signal. The EEG energy was found concentrated at the four basic EEG bands [α (8–13 Hz), β (14–30 Hz), δ (0–4 Hz), and θ (5–7 Hz)]. The analysis revealed that in the presence of EMF, the energy of the β band was significantly greater for females than for males at the majority of the electrodes. Since beta oscillation is associated with the shift of attention during the perception, these findings may indicate that the particular EMF (1,800 MHz signal) exerts an influence on this brain activity, which appears to be gender-related.     

Effect of modulated microwave radiation on human EEG asymmetry

This study is aimed to investigation of the effect of modulated 450 MHz microwave radiation on the EEG inter-hemispheric asymmetry. Ten cycles of the microwave exposure (1 min off and 1 min on) at fixed modulation frequency were applied on two groups of healthy volunteers. The first group of 13 subjects was exposed to microwave radiation modulated at 14 Hz and the second group of 15 subjects at 40 Hz frequency. The peak specific absorption rate (SAR) average over 1 g was 0.303 W/kg. Differences in SAR between hemispheres were up to 20 dB. Rod antenna was located from the left side of the head. Differences of relative changes in EEG energy between symmetric channels FP1–FP2, T3–T4, P3–P4 and O1–O2 in exposed and sham conditions were analysed. The results showed increase in EEG energy from the left side caused by microwave exposure. Statistical analysis done for the whole group of subjects didn’t reveal significant differences in inter-hemispheres asymmetry between exposed and sham conditions. However, statistical analysis performed for individual subjects detected significant differences in asymmetry caused by exposure for 15–35% of individuals.     

Effect of 450 MHz Microwave Modulated with 217 Hz on Human EEG in Rest

Summary This study focuses on discrimination of changes, produced by low-level microwave exposure in intensity and time variability of the human EEG at rest. The power spectral density (PSD) method and nonlinear scaling analysis of the length distribution of low variability periods (LDLVP) were selected for analysis of the EEG signal. During the study, 19 healthy volunteers were exposed to a microwave (450 MHz) of 217 Hz frequency on-off modulation. The field power density at the scalp was 0.16 mW/cm². The experimental protocol consisted of ten cycles of repetitive microwave exposure. Signals from frontal, temporal, parietal and occipital EEG channels on EEG theta, alpha and beta rhythms were analysed. Exposure to microwave causes average increase of EEG activity. LDLVP analysis discriminated significant effect in time variability for 2 subjects (11%). PSD method detected significant changes in intensity for 4 subjects (21%). The effect of low-level microwave exposure is stronger on EEG beta rhythm in temporal and parietal regions of the human brain.     

Individual changes in human EEG caused by 450 MHz microwave modulated at 40 and 70 Hz

This study was aimed to investigate the changes in the human electroencephalographic (EEG) signal caused by modulated low-level microwaves. The 450 MHz microwave exposure modulated at 40 Hz and 70 Hz frequencies was applied to a group of 15 volunteers. The field power density at the scalp was 0.16 mW/cm². Ten cycles of the exposure (1 min on and 1 min off) at both modulation frequencies were applied. Analysis of the EEG signal was performed using three different methods: nonlinear method of scaling analysis for length distribution of low variability periods (LDLVP), relative changes in EEG energy (S-parameter) and beta ratio (H-parameter). The analysis revealed significant changes caused by microwave for the whole group (H-parameter method). The exposure caused increase of the EEG beta power (S-parameter method). Statistically significant changes in EEG were detected for four subjects (26.7%) at 40 Hz modulation frequency (LDLVP method).     

Effect of modulated at different low frequencies microwave radiation on human EEG

This study is aimed to clarify whether effect of low-level microwave radiation on human brain differs at different modulation frequencies. Resting EEG recordings were done on different groups of healthy volunteers. The 450 MHz microwave radiation modulated at 40 and 70 Hz (15 subjects) and 217 and 1,000 Hz (19 subjects) frequencies was applied. The results of our previous study at 7, 14 and 21 Hz modulation were included into analysis. Ten cycles of the exposure (1 min off and 1 min on) at each fixed modulation frequencies were applied. The field power density at the scalp was always 0.16 mW/cm². Our results showed that microwave exposure increased the EEG energy at EEG frequencies lower or close to the modulation frequency. No effect was detected at EEG frequencies higher than the modulation frequency. Statistically significant changes were caused by exposure in the EEG alpha and beta frequency bands; no significant effect was detected in the theta band. Our results suggest that telecommunication devices with complex spectrum of modulation frequencies like mobile phone can affect all human EEG frequency bands.     

Immune stimulation in fish and chicken through weak low frequency electromagnetic fields

A hypothesis is proposed how Low Frequency Electromagnetic Field (LF EMF) exposure can stimulate an immune response, based on recent insights in immunology. We hypothesize that the Immunent EMF treatment induces mild stress to cells, which then produce cytokines that function as alarms or so called danger signals for the immune system. In this way EMF treatment takes the place of multiplying pathogens, and the damage these cause, in the triggering of an immune response. In a first series of experiments in␣vitro common carp head kidney-derived phagocytes were used to determine ROS production as a measure for immune activation. Exposure to LF EMF signals (200–5,000 Hz) at 5 μT or 1.5 mT led to 42 or 33% increase in immune activity, respectively, compared to negative control values. EMF could also additionally stimulate chemically pre-stimulated samples up to 18% (5 μT) or 22% (1.5 mT). Significance of increase in ROS production in the total series was: p < 0.0001. In a second series of experiments in␣vitro commercial goldfish were used. Groups of fish were housed under equal conditions in at least four control tanks and 8–16 EMF-exposed tanks. Exposure was done with a predominantly vertical field at field strengths (rms) between 0.15 and 50 μT. Without treatment mortality was about 50% after 18 days, while the treatment at 5 μT reduced it to 20% on average. At field strengths 0.15, 0.5, 1.5, 5, 15 and 50 μT an equally strong effect was found. Reducing the field strength to 0.05, 0.06, 0.01 and 0.003 μT showed a gradually decreasing effect, which only at 0.003 μT is no longer statistically significant. Finally, in␣vitro experiments were done with 560 commercial broiler chickens exposed to infection pressure from coccidiosis. EMF exposure at 6.5 μT reduced intestinal lesions by 40% and improved feed conversion by 8%.     

EMF effects on microcirculatory system

Authors review the importance of studying the effects of electromagnetic fields (EMF) on microcirculatory system, especially in respect of possibility that vasculature may have direct and indirect role in interaction of static magnetic fields (SMF). We outline the physiological importance of microcirculation and relatively new methods of evaluation technique in vivo and explain in details the local and/or whole body exposure effects of SMF with␣range of 0.3–180 mT, power frequency EMF with range of 0.1–30 mT and microwaves at 1.5 GHz with range 0.08–8 W/kg brain average specific absorption rate (SAR) on microcirculatory systems in different tissues in experimental animals.     

Signal processing and wavelet analysis of simultaneously registered blood pressure and laser Doppler flow signals during extremely low frequency electromagnetic field exposure in humans in vivo

Regulation of microcirculation and other physiological processes have strong non-linear character and involves complex of different processes, every process with own hierarchy in time and different frequencies. Traditional Fourier analysis does not provide sufficient power and resolution to elucidate characteristic of low vasomotor frequencies. Therefore, we apply a Time–frequency (wavelet) analysis on the signal obtained by Laser Doppler flow meter (LDF) at 25 healthy volunteers, exposed at the same time to low frequency electromagnetic fields, used for physiotherapy. Signal processing include Matlab based algorithms for digital signal processing (DSP) and Matlab Spectral analysis toolbox of simultaneous registered variations in Blood Pressure (BP), Laser Doppler Flow (LDF), and Intravital microscopy (IVM). It provides useful information about regulatory mechanisms and vegetative nervous system regulation of peripheral blood flow. Continuous changes in blood pressure variations and perfusion of extremities were measured prior and after 10, 20, and 30 min ELF-EMF (10, 16, 20, and 30 mT), exposure. After wavelet analysis of the blood flow signals and vasomotion changes signals, several frequency bands were distinguished: 0.0095–0.02 Hz; (α), 0.02–0.06 Hz; (β), 0.06–0.15 Hz; (γ), 0.15–0.4 Hz; (δ), and 0.4–1 Hz; (θ) for LDF data and 0.0095–0.4 Hz; (α), 0.4–0.75 Hz; (β), 0.75–0.9 Hz; (γ), 0.9–1.2 Hz; (δ), and 1.2–2 Hz; (θ) for IVM data. In this study, overlapping of some frequency bands between IVM and LDF data were found. Overlapping of the frequency bands has two ways of interpretation, one related with similarity of the structures and tissues and other related with output of ELF-EMF stimulation. We used also correlation and cross-correlation analysis to compare non-invasive (BP measurements and LDF) data, with invasive intravital microscopy (IVM) data (obtained on animals in vivo), during ELF-EMF stimulation. IVM data were used as a reference value, for certain information of possible mechanisms of biological response at the tissue and blood vessel level after ELF-EMF exposure with frequency in the range from 10 to 50 Hz and magnetic flux density of 20 mT. Comparative analysis of IVM and LDF, frequency bands show that they have statistical significant changes after ELF-EMF stimulation. Five subintervals were confirmed (α-, β-, γ-, δ-, and θ). The findings indicate that local ELF-EMF exposure at the constant temperature of the media increases skin blood flow at the upper extremities which have a contribution to the α-frequency band at IVM.     

The frequency-dependent effect of extremely low-frequency electromagnetic field and mechanical vibration at infrasound frequency on the growth, division and motility of Escherichia coli K-12

The aim of this work was to investigate the frequency-dependent effects of extremely low-frequency electromagnetic field (ELF-EMF) and mechanical vibration at infrasound frequency (MV at IS frequency or MV) on growth and development of Escherichia coli K-12, by using classical microbiological (counting colony forming units), isotopic, spectrophotometric and electronmicroscopic methods. The frequency-dependent effects of MV and ELF-EMF were shown that they could either stimulate or inhibit the growth and the division of microbes depending on the periods following exposure. However, the mechanism through which the MV and ELF-EMF effects affect the bacteria cell is not clear yet. It was suggested that the aqua medium could serve a target through which the biological effect of MV and ELF-EMF on microbes could be realized. To check this hypothesis, the frequency-dependent effects (2, 4, 6, 8, 10 Hz) of both MV and ELF-EMF on the bacterial growth, division and their motility in cases of exposure, the preliminary treated microbes-free medium and microbes containing medium were studied. Both MV and ELF-EMF effect on microbes have frequency and post-exposure period duration-dependent characters. The [ ³ H]-thymidine involving experiments shown that EMF at 4 Hz exposure has pronounced stimulation effect on cell proliferation while 4 Hz MV has inhibition effect. But at 8–10 Hz, the both EMF and MV have inhibitory effects on cell proliferation. It is suggested that 4 and 8 Hz EMF have different biological effects on microbes.     

The comparative study of the effects of 4 Hz Electromagnetic Fields-, Infrasound-treated and hydrogen peroxide containing physiological solutions on Na pump-induced inhibition of heart muscle contractility

The effects of 4 Hz extremely low frequency Electromagnetic Fields (ELF EMF), Infrasound (IS) and hydrogen peroxide (H₂O₂) on Na⁺–K⁺ pump-induced transient inhibition of heart muscle contractility was studied. It was documented that EMF-treated and H₂O₂-containing physiological solution had synergic depressing effect on Na⁺–K⁺ pump-induced inhibition of muscle contractility, while the IS had elevation effect on it. On the basis of the obtained data the H₂O₂ could be suggested as the messenger through which the stimulation effect of EMF on heart muscle is realised, while the relaxing effect of IS on heart contractility is due to the decrease of CO₂ solubility of muscle bathing aqueous medium.     

Electromagnetic field levels in the working environment in radio and TV stations

Electromagnetic field sources used for communication always have been subject of serious interest. There are many publications concerning exposure and risk assessment of the working in such environment. Results of epidemiological study performed in Bulgaria in the 1990's show exceeding of the maximal permissible values especially in radio stations for the personnel in 24 h working shift [Israel et al. (1992). Study of the electromagnetic in its influence on personnel working in radio and TV stations, Report, National Centre of Hygiene, Medical Ecology and Nutrition; Israel and Tomov (2001). Epidemiological study of the effects of radiofrequency radiation on operators in radio, TV and relay stations, Proceeding of the Eastern European Regional Meeting and Workshop “Measurements and Criteria for Standard Harmonization in the field of EMF Exposure” and WHO EMF Standards Harmonization Meeting, Varna, Bulgaria, 28 April—3 May, 2001, pp.145–153]. In the last years the situation is strongly influenced by the development of the technology which leads to changes in equipment in radio and TV stations, using lower power, facilitate the working regime. The paper presents data of exposure assessment of different professional groups in selected radio and TV stations. Assessment is being performed on basis of EMF parameters values and energetic load calculations according to the national legislation. Data are compared with the results of previous investigation to evaluate the new situation in this branch. Exposure levels are much lower than those in the previous study, and lower compared to the exposure limits, as well [Israel et al. (1992). Study of the electromagnetic in its influence on personnel working in radio and TV stations, Report, National Centre of Hygiene, Medical Ecology and Nutrition; Israel and Tomov (2001). Epidemiological study of the effects of radiofrequency radiation on operators in radio, TV and relay stations, Proceeding of the Eastern European Regional Meeting and␣Workshop “Measurements and Criteria for Standard Harmonization in the field of EMF Exposure” and WHO EMF Standards Harmonization Meeting, Varna, Bulgaria, 28 April—3 May, 2001, pp.145–153].     

The EMF-induced changes in aqua medium’s properties depend on background ionizing radiation, illumination and temperature

The effects of extremely low-frequency electromagnetic field (ELF EMF) and ELF-modulated millimeter waves (MMW) on physicochemical properties of physiological solution (PS) at different environmental medium were studied. The existence of frequency “windows” at 4 Hz and 8 Hz frequencies of ELF EMF and ELF-modulated MMW which have different effects on heat fusion period (HFP), hydrogen peroxide (H₂O₂) formation and oxygen (O₂) content of water solution and different dependency on temperature, background radiation (BGR) and illumination was shown. The obtained data allow us to suggest that cell bathing medium serving as a target through which the biological effects of ELF EMF and ELF-modulated MMW on cells are realized is extra sensitive to environmental factors. Therefore, the variability of experimental data on EMF biological effects, obtained in different laboratories can be explained by different environmental conditions of experiments, which very often are not considered adequately.     

Changes of Surface Properties of Yeast Cell Wall Under Exposure of Electromagnetic Field (40.68 MHz) and Action of Nystatin

Summary Changes of the surface properties were studied in the cell wall of the yeast Saccharomyces cerevisiae Y-517 under influence of the electromagnetic field (EMF) (40.68 MHz) and lethal doses of the fungicidal antibiotic nystatin (10 μg/10⁶ cells). Atomic force microscopy was used to study surface topography and visco-elastic properties of the cell walls. Surface carbohydrates were detected by lectins marked with gold with the help of the scanning electron microscope. Additional polysaccharide layer appeared over cell surface after EMF exposure. We suggest that electromagnetic fields resulted in the change of the cell surface, and, accordingly, the sensitivity of organisms to the antifungal antibiotics.     

Interlaboratory comparisons in EMF survey measurements

This article presents methods and results of interlaboratory comparison in the electromagnetic field (EMF) survey measurements performed by Electromagnetic Environment Protection Laboratory. Based on the results, the author analyzed factors affecting the precision of EMF measurements, in particular—difficult to estimate—the “human factor”. In practice, the human factor has never been taken into account in the EMF measurements accuracy estimations budget, and the author estimate the importance of this factor that may include even up to half of the total uncertainty of measurements. Taking into account all factors depredating the accuracy of measurements, the uncertainty of the survey EMF measurements was estimated at the level of 2–4 dB.     

Alteration of brain electrical activity by electromagnetic field

To better understand the affect of different levels of EMF on one’s brain activity, the Hodgkin–Huxley model has been used to describe the generation of an active potential in the nerve cell membrane. The theoretical calculations have shown that by the simultaneous affect of both passing an electrical potential and external very low frequency AC, one’s excitation pulses may be suppressed beginning with a certain level of external current. The level of this current depends on the frequency. It is postulated that to eliminate this suppression, the brain increases its normal level relatively to the lower limit. It is also postulated that the brain “tunes up” in the presence of external AC, by increasing the amplitude of its own excitation signals so that suppression does not occur. It is possible that this “tuning” process lasts some time after removing the external EMF as the brain adapts. This has been observed experimentally.     

Mobile communications and health of population: the risk assessment, social and ethical problems

Today world population lives in a new electromagnetic environment, characterized with (i) around the clock enforcement of chronic exposure of all age and gender groups to a wide range of modulated electromagnetic fields (EMF) from base stations; (ii) daily, repeated from early childhood throughout entire life exposure to EMF RF mobile phone the brain and vestibular receptor apparatus and auditory analyzers, located directly “under the EMF beam” in the inner ear. On the other hand, the world science and epidemiology is missing well-planned and executed research results of prolonged exposure of EMF RF on the brain. International recommendations and domestic guidelines do not include changing conditions of RF EMF on the population: the brain has become a critical organ, and the children entered the risk group. The population continues to actively use the mobile phone. In this situation the problem of assessing the risk of mobile communications has become a social and ethical.     

Effects of in vitro exposure to GSM900 electromagnetic field on human erythrocytes

High frequency electromagnetic fields (EMF) are widely used for transmitting of radio and TV signals, in wireless communications, etc. A huge number of people are exposed so the possible risk to human health from telecommunication technologies could be significant even if biological effects are slight. The study of the biological effects of RF EM radiation could contribute to better understanding of the possible health hazards. The levels of released hemoglobin serve as an indicator of hemolysis, caused by increased membrane fragility. This study was designed to investigate the alterations in hemoglobin release after in vitro exposure of human erythrocytes to GSM900 electromagnetic field. Erythrocyte suspensions with two different cell concentrations (hematocrit 20% and 40%) were exposed to EM radiation from GSM mobile phone (carrier frequency 902 MHz, 2 W output power in pulse) for 20 min in two different positions in relation to telephone antenna: Position 1 is in the centre of the major lobe of the azimuth antenna pattern and Position 2 is between major and back lobes. Alterations in hemolysis were registered 0, 10, 20, 30, 40, 50 and 60 min after the treatment. Hemolysis was determined by measuring the absorbance of hemoglobin at 413 nm in the supernatant obtained by centrifuging the suspensions. Hemolysis was expressed as hemoglobin concentration. Our data indicated decrease in the hemoglobin level in irradiated suspensions. The GSM900 EMF exposure probably stabilized erythrocyte membrane and caused reduction in the hemolysis depending on the EMF parameters, on the suspension water content (hematocrit) and on the time elapsed after irradiation.     

Subcutaneous Arteriolar Vasomotion Changes During and After ELF-EMF Exposure in Mice in Vivo

Summary Biological effects of extremely low-frequency electromagnetic fields (ELF-EMF) on microcirculation were investigated in vivo by monitoring arteriole diameters in conscious mice. Measurements of blood vessel diameter were monitored 33 min non-stop before during and after exposure with ELF-EMF and every 389 ms blood vessel diameter were calculated. Using a dorsal skinfold chamber (DSC), and following caudal vein injection of FITC-dextran 250 kDa, the microvasculature (initial arteriole diameter of 45–80 μm), was examined by intravital microscopy and video images were recorded for a total time of 33 min. Arteriole diameter was continuously measured by on-line analysis using a High-speed Digital Machine Vision System CV-2100, using an edge-gap detection algorithm. Since vessel diameters exhibit rhythmic variation expressed by vasomotion, for estimation of microcirculatory activity we used both raw data for frequency analysis of vasomotion (measured frequencies of vasomotion were in the range 0.008÷0.1 Hz) and evaluate mean blood vessel diameter for each 1 min period of time, and make a comparison between Pre, Exposure/Sham exposure and Post exposure periods, with the aim to evaluate possible changes in mean blood vessel diameter as a result of ELF-EMF action. During EMF exposure and post-exposure periods, arteriole diameters increased significantly compared with the pre-exposure period, and the changes were larger during post-exposure. In contrast to sham exposure, vasodilatation of the microvasculature was significantly greater during exposure and post-exposure to 16 Hz EMF. These findings suggest that ELF-EMF may have potential therapeutic use benefit for treating vascular disorders.     

Non-Thermal Effect of Microwave Radiation on Human Brain

Summary This study focuses on an origin of interaction mechanism of microwave radiation with nervous system—quasi-thermal field effect. The microwave field can cause fluctuations and vibration of the charged particles and membranes in tissues. The hypothesis is, that this phenomenon is similar to the effect caused by Brown motion initiated by temperature and results in the same effects without rise in temperature. The electric field of 1 V/cm can introduce disturbance of the thermal equilibrium inside a cell of 10 μm radius, which is equivalent to disturbance produced by temperature rise of 1 K. The hypothesis, that microwave heating should cause an effect independent of the microwave modulation frequency, while field effect depends on modulation frequency, was examined experimentally. The 450 MHz microwave radiation, modulated at 7, 14 and 21 Hz frequencies, power density at the skin 0.16 mW/cm², was applied. The experimental protocol consisted of two series of five cycles of the repetitive microwave exposure at fixed modulation frequencies. Relative changes in EEG theta, alpha and beta rhythms of the group of 13 healthy volunteers were analysed. Analysis of the experimental data shows that: (1) statistically significant changes in EEG rhythms depend on modulation frequency of the microwave field; (2) microwave stimulation causes an increase of the EEG energy level; (3) the effect is most intense at beta1 rhythm and higher modulation frequencies. These findings confirm the quasi-thermal origin of the effect, different from average heating.     

Influence of static magnetic fields on nerve regeneration in vitro

Our research involves determining how non-invasive electric and magnetic fields influence neuronal growth in vitro. In previous studies we have shown that pulsed electromagnetic fields (PEMF) as well as direct current (DC) alone stimulate neurite outgrowth from dorsal root ganglion explants [Sisken et al. 1984; Sisken et al. (Restor Neurol Neurosci 1:303–309, 1990); Greenebaum et al. (Bioelectromagnetics 17:293–302, 1996)]. A maximum response was obtained when nerve growth factor (NGF) was also present in the medium. The results of our experiments using static magnetic fields of different strengths are presented below and indicate that fields of high magnetic strength (450–900 gauss) with added NGF stimulate neurite outgrowth comparable to the response obtained with PEMF plus NGF.