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1.
The present study investigated the possible effects of the electromagnetic field (EMF) emitted by an ordinary GSM mobile phone (902.4 MHz pulsed at 217 Hz) on brainstem auditory processing. Auditory brainstem responses (ABR) were recorded in 17 healthy young adults, without a mobile phone at baseline, and then with a mobile phone on the ear under EMF‐off and EMF‐on conditions. The amplitudes, latencies, and interwave intervals of the main ABR components (waves I, III, V) were compared among the three conditions. ABR waveforms showed no significant differences due to exposure, suggesting that short‐term exposure to mobile phone EMF did not affect the transmission of sensory stimuli from the cochlea up to the midbrain along the auditory nerve and brainstem auditory pathways. Bioelectromagnetics 31:48–55, 2010. © 2009 Wiley‐Liss, Inc.  相似文献   

2.
We investigated whether the pulsed high frequency electromagnetic field (EMF) emitted by a mobile phone has short term effects on the human motor cortex. We measured motor evoked potentials (MEPs) elicited by single pulse transcranial magnetic stimulation (TMS), before and after mobile phone exposure (active and sham) in 10 normal volunteers. Three sites were stimulated (motor cortex (CTX), brainstem (BST) and spinal nerve (Sp)). The short interval intracortical inhibition (SICI) of the motor cortex reflecting GABAergic interneuronal function was also studied by paired pulse TMS method. MEPs to single pulse TMS were also recorded in two patients with multiple sclerosis showing temperature dependent neurological symptoms (hot bath effect). Neither MEPs to single pulse TMS nor the SICI was affected by 30 min of EMF exposure from mobile phones or sham exposure. In two MS patients, mobile phone exposure had no effect on any parameters of MEPs even though conduction block occurred at the corticospinal tracts after taking a bath. As far as available methods are concerned, we did not detect any short-term effects of 30 min mobile phone exposure on the human motor cortical output neurons or interneurons even though we can not exclude the possibility that we failed to detect some mild effects due to a small sample size in the present study. This is the first study of MEPs after electromagnetic exposure from a mobile phone in neurological patients.  相似文献   

3.
To investigate possible health effects of mobile phone use, we conducted a double-blind, cross-over provocation study to confirm whether subjects with mobile phone related symptoms (MPRS) are more susceptible than control subjects to the effect of electromagnetic fields (EMF) emitted from base stations. We sent questionnaires to 5,000 women and obtained 2,472 valid responses from possible candidates; from these, we recruited 11 subjects with MPRS and 43 controls. There were four EMF exposure conditions, each of which lasted 30 min: continuous, intermittent, and sham exposure with and without noise. Subjects were exposed to EMF of 2.14 GHz, 10 V/m (W-CDMA), in a shielded room to simulate whole-body exposure to EMF from base stations, although the exposure strength we used was higher than that commonly received from base stations. We measured several psychological and cognitive parameters pre- and post-exposure, and monitored autonomic functions. Subjects were asked to report on their perception of EMF and level of discomfort during the experiment. The MPRS group did not differ from the controls in their ability to detect exposure to EMF; nevertheless they consistently experienced more discomfort, regardless of whether or not they were actually exposed to EMF, and despite the lack of significant changes in their autonomic functions. Thus, the two groups did not differ in their responses to real or sham EMF exposure according to any psychological, cognitive or autonomic assessment. In conclusion, we found no evidence of any causal link between hypersensitivity symptoms and exposure to EMF from base stations.  相似文献   

4.
Potential effects of a 30 min exposure to third generation (3G) Universal Mobile Telecommunications System (UMTS) mobile phone‐like electromagnetic fields (EMFs) were investigated on human brain electrical activity in two experiments. In the first experiment, spontaneous electroencephalography (sEEG) was analyzed (n = 17); in the second experiment, auditory event‐related potentials (ERPs) and automatic deviance detection processes reflected by mismatch negativity (MMN) were investigated in a passive oddball paradigm (n = 26). Both sEEG and ERP experiments followed a double‐blind protocol where subjects were exposed to either genuine or sham irradiation in two separate sessions. In both experiments, electroencephalograms (EEG) were recorded at midline electrode sites before and after exposure while subjects were watching a silent documentary. Spectral power of sEEG data was analyzed in the delta, theta, alpha, and beta frequency bands. In the ERP experiment, subjects were presented with a random series of standard (90%) and frequency‐deviant (10%) tones in a passive binaural oddball paradigm. The amplitude and latency of the P50, N100, P200, MMN, and P3a components were analyzed. We found no measurable effects of a 30 min 3G mobile phone irradiation on the EEG spectral power in any frequency band studied. Also, we found no significant effects of EMF irradiation on the amplitude and latency of any of the ERP components. In summary, the present results do not support the notion that a 30 min unilateral 3G EMF exposure interferes with human sEEG activity, auditory evoked potentials or automatic deviance detection indexed by MMN. Bioelectromagnetics 34:31–42, 2013. © 2012 Wiley Periodicals, Inc.  相似文献   

5.
Previous studies on the effects of the mobile phone electromagnetic field (EMF) on various event‐related potential (ERP) components have yielded inconsistent and even contradictory results, and often failed in replication. The mismatch negativity (MMN) is an auditory ERP component elicited by infrequent (deviant) stimuli differing in some physical features from the repetitive frequent (standard) stimuli in a sound sequence. The MMN provides a sensitive measure for cortical auditory stimulus feature discrimination, regardless of attention and other contaminating factors. In this study, MMN responses to duration, intensity, frequency, and gap changes were recorded in healthy young adults (n = 17), using a multifeature paradigm including several types of auditory change in the same stimulus sequence, while a GSM mobile phone was placed on either ear with the EMF (902 MHz pulsed at 217 Hz; SAR1g = 1.14 W/kg, SAR10g = 0.82 W/kg, peak value = 1.21 W/kg, measured with an SAM phantom) on or off. An MMN was elicited by all deviant types, while its amplitude and latency showed no significant differences due to EMF exposure for any deviant types. In the present study, we found no conclusive evidence that acute exposure to GSM mobile phone EMF affects cortical auditory change detection processing reflected by the MMN. Bioelectromagnetics 30:241–248, 2009. © 2009 Wiley‐Liss, Inc.  相似文献   

6.
The widespread use of the mobile phone has initiated many studies on the possible adverse effects of a high frequency electromagnetic field (EMF), which is used in mobile phones. A low frequency EMF is reported to suppress melatonin synthesis. The aim of this study was to clarify the effects on melatonin synthesis in rats after short term exposure to a 1439 MHz time division multiple access (TDMA) EMF. The average specific absorption ratio (SAR) of the brain was 7.5 W/kg, and the average SARs of the whole body were 1.9 and 2.0 W/kg for male and female rats, respectively. A total of 208 male and female rats were investigated. After acclimatization to a 12 h light-dark (LD) cycle, serum and pineal melatonin levels together with pineal serotonin level under a dark condition (less than 1 lux) were examined by radioimmunoassay. No significant differences in melatonin and serotonin levels were observed between the exposure, sham, and cage control groups. These results suggest that short term exposure to a 1439 MHz TDMA EMF, which is about four times stronger than that emitted by mobile phones, does not alter melatonin and serotonin synthesis in rats. Further investigations on the effects of long term exposure are warranted.  相似文献   

7.
We studied the effects of an electromagnetic field (EMF) as emitted by a 902 MHz mobile phone on human short term memory. This study was a replication with methodological improvements to our previous study. The improvements included multi-centre testing and a double blind design. A total of 64 subjects (32 men) in two independent laboratories performed a short term memory task (n-back) which poses a varying memory load (0-3 items) on the subjects' memory. They performed the task twice, once each under EMF and sham exposure. Reaction times (RTs) and accuracy of the responses were recorded. The order of exposure and memory load conditions were counterbalanced across subjects and gender. There were no statistically significant differences in performance between the two laboratories. We could not replicate our previous results: the EMF had no effect on RTs or on the accuracy of the subjects' answers. The inability to replicate previous findings could have been caused by lack of actual EMF effects or the magnitude of effects being at the sensitivity threshold of the test used.  相似文献   

8.
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. Bioelectromagnetics 32:179–190, 2011. © 2010 Wiley‐Liss, Inc.  相似文献   

9.
This study was designed to test whether extremely low frequency electromagnetic field (ELF‐EMF) could enhance the apoptosis‐induction effect of X‐ray radiotherapy on liver cancer cell line BEL‐7402 in vitro. EMF exposure was performed inside an energized solenoid coil. X‐ray irradiation was performed using a linear accelerator. Apoptosis rates of BEL‐7402 cells were analyzed using Annexin V‐Fit Apoptosis Detection kit. Apoptosis rates of EMF group and sham EMF group were compared when combined with X‐ray irradiation. Our results suggested that the apoptosis rate of BEL‐7402 cells exposed to low doses of X‐ray irradiation could be significantly increased by EMF. More EMF exposures obtain significantly higher apoptosis rates than fewer EMF exposures when combined with 2 Gy X‐ray irradiation. These findings suggested that ELF‐EMF could augment the cell apoptosis effects of low doses of X‐ray irradiation on BEL‐7402 cells in a synergistic and cumulative way. Bioelectromagnetics 30:163–165, 2009. © 2008 Wiley‐Liss, Inc.  相似文献   

10.
The fourth course at the International School of Bioelectromagnetics addressed various aspects of the epidemiology of exposure to electromagnetic fields (EMF). In this overview, inspired by the lectures and the discussions among participants, we summarize current knowledge on exposure to EMF and disease risk, with emphasis on studies of use of mobile phones and brain tumours and exposure to power lines and childhood leukaemia. Sources of bias and error hamper straightforward conclusions in some areas and, in order to move forward, improvements in study design and exposure assessment are necessary. The scientific evidence available to date on possible long‐term effects from exposure to ELF and RF fields is not strong enough to revise current protection limits based on the known acute effects of such exposures. Precautionary measures may be considered to reduce ELF exposure of children or exposure to RF during mobile phone use, keeping in mind that it is unclear whether they involve any preventive benefit. Possible health effects from mobile phone use in adults and in children should be investigated further by prospective epidemiological studies with improved exposure assessment and brain tumour incidence rates should be monitored. Further studies on the relation between childhood leukaemia and ELF magnetic fields would be worthwhile if they focus on heavily exposed groups and attempt to minimize possible selection bias. In conclusion, epidemiological studies conducted with appropriate diligence can play a key role in finding the answers. Bioelectromagnetics 30:511–524, 2009. © 2009 Wiley‐Liss, Inc.  相似文献   

11.
We investigated the effect of mobile phone use on the auditory sensory memory in children. Auditory event‐related potentials (ERPs), P1, N2, mismatch negativity (MMN), and P3a, were recorded from 17 children, aged 11–12 years, in the recently developed multi‐feature paradigm. This paradigm allows one to determine the neural change‐detection profile consisting of several different types of acoustic changes. During the recording, an ordinary GSM (Global System for Mobile Communications) mobile phone emitting 902 MHz (pulsed at 217 Hz) electromagnetic field (EMF) was placed on the ear, over the left or right temporal area (SAR1g = 1.14 W/kg, SAR10g = 0.82 W/kg, peak value = 1.21 W/kg). The EMF was either on or off in a single‐blind manner. We found that a short exposure (two 6 min blocks for each side) to mobile phone EMF has no statistically significant effects on the neural change‐detection profile measured with the MMN. Furthermore, the multi‐feature paradigm was shown to be well suited for studies of perception accuracy and sensory memory in children. However, it should be noted that the present study only had sufficient statistical power to detect a large effect size. Bioelectromagnetics 31:191–199, 2010. © 2009 Wiley‐Liss, Inc.  相似文献   

12.
The European multicenter project named GUARD involved nine centers and aimed to assess potential changes in auditory function as a consequence of exposure to low-intensity electromagnetic fields (EMFs) produced by GSM cellular phones. Participants were healthy young adults without any evidence of hearing or ear disorders. Auditory function was assessed immediately before and after exposure to EMFs, and only the exposed ear was tested. The procedure was conducted twice in a double blinded design, once with a genuine EMF exposure and once with a sham exposure (at least 24 h apart). Tests for assessment of auditory function were hearing threshold level (HTL), transient otoacoustic emissions (TEOAE), distortion product otoacoustic emissions (DPOAE), and auditory brainstem response (ABR). The exposure consisted of speech at a typical conversational level delivered via an earphone to one ear, plus genuine or sham EMF exposure. The EMF exposure used the output of a software-controlled consumer cellular phone at full power for 10 min. A system of phone positioning that allowed participants to freely move their heads without affecting exposure was used. Analysis of the data showed there were no effects of exposure to GSM mobile phone signals on the main measures of the status of the auditory system.  相似文献   

13.
The present study was designed to evaluate whether gestational exposure to an EMF targeting the head region, similar to that from cellular phones, might affect embryogenesis in rats. A 1.95‐GHz wide‐band code division multiple access (W‐CDMA) signal, which is one applied for the International Mobile Telecommunication 2000 (IMT‐2000) system and used for the freedom of mobile multimedia access (FOMA), was employed for exposure to the heads of four groups of pregnant CD(SD) IGS rats (20 per group) for gestational days 7–17. The exposure was performed for 90 min/day in the morning. The spatial average specific absorption rate (SAR) for individual brains was designed to be 0.67 and 2.0 W/kg with peak brain SARs of 3.1 and 7.0 W/kg for low (group 3) and high (group 4) exposures, respectively, and a whole‐body average SAR less than 0.4 W/kg so as not to cause thermal effects due to temperature elevation. Control and sham exposure groups were also included. At gestational day 20, all dams were killed and fetuses were taken out by cesarean section. There were no differences in maternal body weight gain. No adverse effects of EMF exposure were observed on any reproductive and embryotoxic parameters such as number of live (243–271 fetuses), dead or resorbed embryos, placental weights, sex ratios, weights or external, visceral or skeletal abnormalities of live fetuses. Bioelectromagnetics 30:205–212, 2009. © 2008 Wiley‐Liss, Inc.  相似文献   

14.
With the number of cellular phone users rapidly increasing, there is a considerable amount of public concern regarding the effects that electromagnetic fields (EMFs) from cellular phones have on health. People with self‐attributed electromagnetic hypersensitivity (EHS) complain of subjective symptoms such as headaches, insomnia, and memory loss, and attribute these symptoms to radio frequency (RF) radiation from cellular phones and/or base stations. However, EHS is difficult to diagnose because it relies on a person's subjective judgment. Various provocation studies have been conducted on EHS caused by Global System for Mobile Communications (GSM) phones in which heart rate and blood pressure or subjective symptoms were investigated. However, there have been few sham‐controlled provocation studies on EHS with Code Division Multiple Access (CDMA) phones where physiological parameters, subjective symptoms, and perception of RF radiation for EHS and non‐EHS groups were simultaneously investigated. In this study, two volunteer groups of 18 self‐reported EHS and 19 non‐EHS persons were tested for both sham and real RF exposure from CDMA cellular phones with a 300 mW maximum exposure that lasted half an hour. We investigated not only the physiological parameters such as heart rate, respiration rate, and heart rate variability (HRV), but also various subjective symptoms and the perception of EMF. In conclusion, RF exposure did not have any effects on physiological parameters or subjective symptoms in either group. As for EMF perception, there was no evidence that the EHS group better perceived EMF than the non‐EHS group. Bioelectromagnetics 30:641–650, 2009. © 2009 Wiley‐Liss, Inc.  相似文献   

15.
The potential health risks of radiofrequency electromagnetic fields (EMFs) emitted by mobile phones are of considerable public interest. The present study investigated the hypothesis, based on the results of our previous study, that exposure to EMFs can increase sympathetic vasoconstrictor activity. Forty healthy young males and females underwent a single-blind, placebo-controlled protocol once on each of two different days. Each investigation included successive periods of placebo and EMF exposure, given in a randomized order. The exposure was implemented by a GSM-like signal (900 MHz, pulsed with 217 Hz, 2 W) using a mobile phone mounted on the right-hand side of the head in a typical telephoning position. Each period of placebo exposure and of EMF exposure consisted of 20 min of supine rest, 10 min of 70 degrees upright tilt on a tilt table, and another 20 min of supine rest. Blood pressure, heart rate and cutaneous capillary perfusion were measured continuously. In addition, serum levels of norepinephrine, epinephrine, cortisol and endothelin were analyzed in venous blood samples taken every 10 min. Similar to the previous study, systolic and diastolic blood pressure each showed slow, continuous, statistically significant increases of about 5 mmHg during the course of the protocol. All other parameters either decreased in parallel or remained constant. However, analysis of variance showed that the changes in blood pressure and in all other parameters were independent of the EMF exposure. These findings do not support the assumption of a nonthermal influence of EMFs emitted by mobile phones on the cardiovascular autonomic nervous system in healthy humans.  相似文献   

16.
There is widespread public concern about the potential adverse health effects of mobile phones in general and their associated base stations in particular. This study was designed to investigate the acute effects of radio frequency (RF) electromagnetic fields (EMF) emitted by the Universal Mobile Telecommunication System (UMTS) mobile phone base stations on human cognitive function and symptoms. Forty adolescents (15-16 years) and 40 adults (25-40 years) were exposed to four conditions: (1) sham, (2) a Continuous Wave (CW) at 2140 MHz, (3) a signal at 2140 MHz modulated as UMTS and (4) UMTS at 2140 MHz including all control features in a randomized, double blinded cross-over design. Each exposure lasted 45 min. During exposure the participants performed different cognitive tasks with the Trail Making B (TMB) test as the main outcome and completed a questionnaire measuring self reported subjective symptoms. No statistically significant differences between the UMTS and sham conditions were found for performance on TMB. For the adults, the estimated difference between UMTS and sham was -3.2% (-9.2%; 2.9%) and for the adolescents 5.5% (-1.1%; 12.2%). No significant changes were found in any of the cognitive tasks. An increase in 'headache rating' was observed when data from the adolescents and adults were combined (P = 0.027), an effect that may be due to differences at baseline. In conclusion, the primary hypothesis that UMTS radiation reduces general performance in the TMB test was not confirmed. However, we suggest that the hypothesis of subjective symptoms and EMF exposure needs further research.  相似文献   

17.
Several studies show increases in activity for certain frequency bands (10–14 Hz) and visually scored parameters during sleep after exposure to radiofrequency electromagnetic fields. A shortened REM latency has also been reported. We investigated the effects of a double‐blind radiofrequency exposure (884 MHz, GSM signaling standard including non‐DTX and DTX mode, time‐averaged 10 g psSAR of 1.4 W/kg) on self‐evaluated sleepiness and objective EEG measures during sleep. Forty‐eight subjects (mean age 28 years) underwent 3 h of controlled exposure (7:30–10:30 PM; active or sham) prior to sleep, followed by a full‐night polysomnographic recording in a sleep laboratory. The results demonstrated that following exposure, time in Stages 3 and 4 sleep (SWS, slow‐wave sleep) decreased by 9.5 min (12%) out of a total of 78.6 min, and time in Stage 2 sleep increased by 8.3 min (4%) out of a total of 196.3 min compared to sham. The latency to Stage 3 sleep was also prolonged by 4.8 min after exposure. Power density analysis indicated an enhanced activation in the frequency ranges 0.5–1.5 and 5.75–10.5 Hz during the first 30 min of Stage 2 sleep, with 7.5–11.75 Hz being elevated within the first hour of Stage 2 sleep, and bands 4.75–8.25 Hz elevated during the second hour of Stage 2 sleep. No pronounced power changes were observed in SWS or for the third hour of scored Stage 2 sleep. No differences were found between controls and subjects with prior complaints of mobile phone‐related symptoms. The results confirm previous findings that RF exposure increased the EEG alpha range in the sleep EEG, and indicated moderate impairment of SWS. Furthermore, reported differences in sensitivity to mobile phone use were not reflected in sleep parameters. Bioelectromagnetics 32:4–14, 2011. © 2010 Wiley‐Liss, Inc.  相似文献   

18.
Individuals who report sensitivity to electromagnetic fields often report cognitive impairments that they believe are due to exposure to mobile phone technology. Previous research in this area has revealed mixed results, however, with the majority of research only testing control individuals. Two studies using control and self‐reported sensitive participants found inconsistent effects of mobile phone base stations on cognitive functioning. The aim of the present study was to clarify whether short‐term (50 min) exposure at 10 mW/m2 to typical Global System for Mobile Communication (GSM) and Universal Mobile Telecommunications System (UMTS) base station signals affects attention, memory, and physiological endpoints in sensitive and control participants. Data from 44 sensitive and 44 matched‐control participants who performed the digit symbol substitution task (DSST), digit span task (DS), and a mental arithmetic task (MA), while being exposed to GSM, UMTS, and sham signals under double‐blind conditions were analyzed. Overall, cognitive functioning was not affected by short‐term exposure to either GSM or UMTS signals in the current study. Nor did exposure affect the physiological measurements of blood volume pulse (BVP), heart rate (HR), and skin conductance (SC) that were taken while participants performed the cognitive tasks. Bioelectromagnetics 30:556–563, 2009. © 2009 Wiley‐Liss, Inc.  相似文献   

19.
Modern mobile phones emit electromagnetic fields (EMFs) ranging from 900 to 2000 MHz which are suggested to have an influence on well-being, attention and neurological parameters in mobile phone users. To date most studies have investigated Global System for Mobile Communications (GSM)-EMF and only very few studies were concerned with Universal Mobile Telecommunications System (UMTS)-EMF. Consequently, we tested the effects of both types of EMF, 1950 MHz UMTS (SAR 0.1 and 1 W/kg) and pulsed 900 MHz GSM (1 W/kg), on well-being and vigilance-controlled resting electroencephalogram (eyes closed) in 15 healthy, right-handed subjects. A double-blind, randomised, crossover application of the test procedure was used. Neither the UMTS- nor the GSM-EMF produced any significant changes in the measured parameters compared to sham exposure. The results do not give any evidence for a deleterious effect of the EMF on normal healthy mobile phone users.  相似文献   

20.
Modern mobile phones emit electromagnetic fields (EMF) ranging from 900 to 2000 MHz which are suggested to have an influence on well-being, attention and neurological parameters in mobile phone users. Until now most studies have investigated Global System for Mobile Communications (GSM)-EMF and only very few studies have focused on Universal Mobile Telecommunications System (UMTS)-EMF. Therefore, we tested the effects of both types of unilaterally presented EMF, 1950 UMTS (0.1 and 1 W/kg) and pulsed 900 MHz GSM (1 W/kg), on visually evoked occipital P100, the P300 of a continuous performance test, auditory evoked central N100 and the P300 during an oddball task as well as on the respective behavioral parameters, reaction time and false reactions, in 15 healthy, right handed subjects. A double-blind, randomized, crossover application of the test procedure was used. Neither the UMTS- nor the GSM-EMF produced any significant changes in the measured parameters compared to sham exposure. The results do not give any evidence for a deleterious effect of the EMF on normal healthy mobile phone users.  相似文献   

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