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Mobile Phone Exposure and Spatial Memory
Abstract
Radiofrequency (RF) emission during mobile phone use has been suggested to impair cognitive functions, that is, working memory. This study investigated the effects of a 2 1/2 h RF exposure (884 MHz) on spatial memory and learning, using a double-blind repeated measures design. The exposure was designed to mimic that experienced during a real-life mobile phone conversation. The design maximized the exposure to the left hemisphere. The average exposure was peak spatial specific absorption rate (psSAR10g) of 1.4 W/kg. The primary outcome measure was a "virtual" spatial navigation task modeled after the commonly used and validated Morris Water Maze. The distance traveled on each trial and the amount of improvement across trials (i.e., learning) were used as dependent variables. The participants were daily mobile phone users, with and without symptoms attributed to regular mobile phone use. Results revealed a main effect of RF exposure and a significant RF exposure by group effect on distance traveled during the trials. The symptomatic group improved their performance during RF exposure while there was no such effect in the non-symptomatic group. Until this new finding is further investigated, we can only speculate about the cause.
... Therefore, in our experiments metallic shields were not used. When choosing the suitable material, we have learned that several layers of an ordinary polyethylene film (PF) are able to modify or to shield such kind of radiation (Veinik, 1991). The polyethylene (-CH 2 -CH 2 -)n is an unusual solid in that it solidifies in long, kinked chains consisting of individual CH 2 units. ...
... It is supposed that the energy-loss mechanism like above described could occur during a propagation of the AIR across the PF. According to (Veinik, 1991;Detela, 2001) and other authors the AIR consists of the charged particles having extremely small diameter (~ 1.6 ×10 −32 m) and mass (~1.2×10 −3 × m e , where m e − is the mass of an electron). It is not surprising that the AIR, modified by the PF can change its physical and, in turn, biological properties. ...
... ) EMF exposure(Arendash at el., 2010).Wiholm et al. (2009) studied spatial behavior and learning (a virtual Morris watermaze) in subjects with (N=23) and without (N=19) symptoms related to mobile phone use. The design was both double-blind and crossover, and the exposure (884 MHz, SAR value, 1.4 W/kg) lasted for 2.5 hours. Spatial performance was measured before and after the exposure and the o ...
... Likewise , accuracy of performance was reduced [18,19] and elevated [11,12,33,34] in several experiments. Additional findings refer to increased verbal memory and visuospatial working memory capacity [29], a reduction of false alarms [15], a decreased retrieval efficiency [31] and a reduced distance traveled in the Virtual Morris Water Task [35]. More than half of the reviewed studies observed no behavioral changes at all (Table 1 and 2). ...
... In the reviewed literature , the majority of studies assessed performance during exposure (seeTable 1 and 2), yet it seems that in a few cases the task duration did not necessarily match or even exceeded the exposure duration (e.g.222324). Performance was also measured before and/or after exposure [29,35,43,57], before and during the second part of exposure [31], before, during and after exposure [47], during the last 10 minutes of exposure [11,12,58], as well as exclusively after exposure [26] . Hence, it cannot be excluded that the current inconsistencies in cognitive outcomes may at least be partially due to the high variability in timing of tasks with respect to exposure. ...
... To date, durations of short term exposure vary from 10- 20 minutes [21,33,34] to 150 minutes [35]. Within a sleep study (variable exposure duration of 6.45-8.56 ...
The steady increase of mobile phone usage has led to a rising concern about possible adverse health effects of radio frequency electromagnetic field (RF EMF) exposure at intensities even below the existing safety limits. Accumulating evidence suggests that pulse-modulated RF EMF may alter brain physiology. Yet, whereas effects on the human electroencephalogram in waking and sleep have repeatedly been shown in recent years, results on cognitive performance are inconsistent.
This review compares 41 provocation studies regarding the effects of RF EMF exposure similar to mobile telephones on cognitive performance measures in humans. The studies were identified via systematic searches of the databases Pub Med and ISI Web of Science and were published in peer-reviewed journals between 1998 and the end of 2009.
Based on a critical discussion within the scope of methodological standards it is concluded that state-of-the-art-methods in bio-electromagnetic research on RF EMF effects and cognition have neither been specified nor fully implemented over the last 10-11 years. The lack of a validated tool, which reliably assesses changes in cognitive performance caused by RF EMF exposure, may contribute to the current inconsistencies in outcomes. The high variety of findings may also be due to methodological issues such as differences in sample size and the composition of study groups, experimental design, exposure setup as well as the exposure conditions, and emphasizes the need for a standardized protocol in bioelectromagnetic research.
At present, no underlying biological mechanism has been identified which mediates the effects on brain functioning as observed in electroencephalographic (EEG) studies. A future aim must be to identify this mechanism as well as a reliable exposure protocol in order to gain more insights into possible behavioral and related health consequences of high-frequency EMF exposure.
... Twenty-nine studies met our inclusion criteria. One of the included studies was described in three articles and one meeting abstract, each broadly relating to a different set of endpoints Hillert et al., 2007Hillert et al., , 2008Wiholm et al., 2009]. For ease of reference, we describe this study in our text by the study's acronym, ''MPDHE'' (Mobile Phones and Direct Health Effects), together with the specific citation containing relevant data. ...
... In all of these studies (Table 5), participants were only exposed to EMF from VDUs. EMF Hietanen et al. [2002], Mueller and Schierz [2004], Rea et al. [1991], Trimmel and Schweiger [1998], MPDHE study Hillert et al., 2007Hillert et al., , 2008Wiholm et al., 2009]. b Some totals do not add to 100 % because of rounding. ...
... Cognitive functions were tested in seven studies, in which all but one used mobile phone-related exposures (Table 7). Two studies resulted in at least one positive finding for IEI-EMF participants [Trimmel and Schweiger, 1998;Wiholm et al., 2009]. Trimmel and Schweiger [1998] observed reduced performance of visual attention and perception by combining a 50 Hz magnetic field with acoustic noise exposure, compared to the effects of noise only. ...
Idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF) is a controversial illness in which people report symptoms that they believe are triggered by exposure to EMF. Double-blind experiments have found no association between the presence of EMF and self-reported outcomes in people with IEI-EMF. No systematic review has assessed whether EMF exposure triggers physiological or cognitive changes in this group. Using a systematic literature search, we identified 29 single or double-blind experiments in which participants with IEI-EMF were exposed to different EMF levels and in which objectively measured outcomes were assessed. Five studies identified significant effects of exposure such as reduced heart rate and blood pressure, altered pupillary light reflex, reduced visual attention and perception, improved spatial memory, movement away from an EMF source during sleep and altered EEG during sleep. In most cases, these were isolated results that other studies failed to replicate. For the sleep EEG findings, the results reflected similar changes in the IEI-EMF participants and a non-IEI-EMF control group. At present, there is no reliable evidence to suggest that people with IEI-EMF experience unusual physiological reactions as a result of exposure to EMF. This supports suggestions that EMF is not the main cause of their ill health.
... Previous studies demonstrated that the brain is one of the most sensitive organs to EMF radiation. Under certain conditions, EMF exposure is considered to be associated with altered blood-brain barrier (BBB) permeability 1,2 , memory and learning function 3,4 , and physiological indexes 5 . ...
... Most of the voxel rat models have taken rat brain as a unified structure, although some of them considered substructures of rat brains such as white matter, grey matter, thalamus, and cerebellum 3,8,14,16 . The segmentation of rat brain voxel model can provide more accurate BRSAR which is essential especially for the studies focusing on biological effects induced by EMF on specific brain regions and their related functions (e.g. the hippocampus and memory). ...
... evaluation of 1.95 GHz RF radiation. Most of these voxel rat models have taken rats' brain as a unified structure, though some researchers have considered the SAR value of white matter, grey matters, thalamus, and cerebellum, etc. 3,8,14,16 . However, none of these studies have segmented rat brains into sub-regions directly related to certain functions (e.g. ...
Accurate dosimetry of a specific brain region in rats exposed to an electromagnetic field (EMF) is essential for studies focusing on dose-effect relationship of the region. However, only dosimetry of whole brain or whole body were evaluated in most of previous studies. In this study, a numerical voxel rat model with 10 segmented brain regions was constructed. Then, the effects of frequency, incidence direction, and E-polarization direction of plane wave EMF on brain region averaged specific absorption rate (BRSAR) of rats were investigated. At last, the reliability of using whole-body averaged SAR (WBDSAR) and whole-brain averaged SAR (WBRSAR) as estimations of BRSAR were also evaluated. Our results demonstrated that the BRSAR depended on the frequency, incidence direction, and E-polarization direction of the EMF. Besides, the largest deviation could be up to 13.1 dB between BRSAR and WBDSAR and 9.59 dB between BRSAR and WBRSAR. The results suggested that to establish an accurate dose-effect relationship, the variance of the BRSAR induced by alteration of frequency, incidence direction, and E-polarization direction of EMF should be avoided or carefully evaluated. Furthermore, the use of WBDSAR and WBRSAR as estimations of BRSAR should be restricted to certain conditions such that the deviations are not too large.
... In some cases minor health symptoms have been reported [6], as well as behavioral problems in children exposed prenatally to mobile phone radiation [7]. Clinical studies in humans, mainly involving volunteers, have shown possible effects on sleeping conditions and memory function [8]. At the same, individual's level, lab animal studies are very extensive and have been using sophisticated techniques including gene and protein expression studies, proteomics, development and reproduction following EMF exposure. ...
... Free moving mice were exposed within their cages, as also followed in rats [23] [33]. We exposed the mice to a daily dose of GSM 900 MHz in speaking mode, for four consecutive days and took advantage of the Morris water maze behavioral task, since spatial navigation is a complex cognitive function that depends on several neural and cognitive systems for successful completion [8]. In this task mice are placed for four consecutive days (training period) into a large circular pool of water from which they can escape onto a slightly submerged platform. ...
Cancer morbidity was registered in the whole population of military career personnel in Poland during a period of 15 years (1971-1985). Subjects exposed occupationally to radiofrequencies (RF) and microwaves (MW) were selected from the population on the basis of their service records and documented exposures at service posts. The population size varied slightly from year to year with a mean count of about 128,000 persons each year; each year about 3700 of them (2.98%) were considered as occupationally exposed to RF/MW. All subjects (exposed and non-exposed to RF/MW) were divided into age groups (20-29, 30-39, 40-49 and 50-59). All newly registered cases of cancer were divided into 12 types based on localisation of the malignancy; for neoplasms of the haemopoietic system and lymphatic organs an additional analysis based on diagnosis was performed. Morbidity rates (per 100,000 subjects annually) were calculated for all of the above localisations and types of malignancies both for the whole population and for the age groups. The mean value of 15 annual rates during 1971-1985 represented the respective morbidity rate for the whole period. Morbidity rates in the non-exposed groups of personnel were used as 'expected' (E) rates for the exposed subjects, while the real morbidity rates counted in the RF/MW-exposed personnel served as 'observed' (O) rates. This allowed the calculation of the observed/expected ratio (OER) representing the odds ratio for the exposed groups. The cancer morbidity rate for RF/MW-exposed personnel for all age groups (20-59 years) reached 119.1 per 100,000 annually (57.6 in non-exposed) with an OER of 2.07, significant at P < 0.05. The difference between observed and expected values results from higher morbidity rates due to neoplasms of the alimentary tract (OER = 3.19-3.24), brain tumours (OER = 1.91) and malignancies of the haemopoietic system and lymphatic organs (OER = 6.31). Among malignancies of the haemopoietic/lymphatic systems, the largest differences in morbidity rates between exposed and non-exposed personnel were found for chronic myelocytic leukaemia (OER = 13.9), acute myeloblastic leukaemia (OER = 8.62) and non-Hodgkin lymphomas (OER = 5.82).
... In some cases minor health symptoms have been reported [6], as well as behavioral problems in children exposed prenatally to mobile phone radiation [7]. Clinical studies in humans, mainly involving volunteers, have shown possible effects on sleeping conditions and memory function [8]. At the same, individual's level, lab animal studies are very extensive and have been using sophisticated techniques including gene and protein expression studies, proteomics, development and reproduction following EMF exposure. ...
... Free moving mice were exposed within their cages, as also followed in rats [23,33]. We exposed the mice to a daily dose of GSM 900 MHz in speaking mode, for four consecutive days and took advantage of the Morris water maze behavioral task, since spatial navigation is a complex cognitive function that depends on several neural and cognitive systems for successful completion [8]. In this task mice are placed for four consecutive days (training period) into a large circular pool of water from which they can escape onto a slightly submerged platform. ...
Extended work has been performed worldwide on the effects of mobile phone radiation upon rats' cognitive functions, however there is great controversy to the existence or not of deficits. The present work has been designed in order to test the effects of mobile phone radiation on spatial learning and memory in mice Mus musculus Balb/c using the Morris water maze (a hippocampal-dependent spatial memory task), since there is just one other study on mice with very low SAR level (0.05W/kg) showing no effects. We have applied a 2h daily dose of pulsed GSM 900MHz radiation from commercially available mobile phone for 4 days at SAR values ranging from 0.41 to 0.98W/kg. Statistical analysis revealed that during learning, exposed animals showed a deficit in transferring the acquired spatial information across training days (increased escape latency and distance swam, compared to the sham-exposed animals, on the first trial of training days 2-4). Moreover, during the memory probe-trial sham-exposed animals showed the expected preference for the target quadrant, while the exposed animals showed no preference, indicating that the exposed mice had deficits in consolidation and/or retrieval of the learned spatial information. Our results provide a basis for more thorough investigations considering reports on non-thermal effects of electromagnetic fields (EMFs).
... Une méta-analyse conduite sur dix études [31] concernant les effets des signaux GSM sur les fonctions d'attention et de mémoire révélait une réduction du TR dans les tâches de soustraction ( = −0,09, 95 % CI : −0,16 to −0,02), et dans le test « 0-back target » ( = −0,04, 95 % CI : -0,06 à -0,02). Wiholm et al. [32] ont rapporté que les performances de navigation virtuelle chez un groupe de sujets hypersensibles étaient améliorées à la suite d'une exposition réelle. ...
... De même, malgré des tendances, les TR dans les tâches simples ( P < 0, 026) et de soustraction ( P < 0,044) n'ont pas atteint la significativité statistique après correction en lien avec les tests multiples (14 tests) [25,26]. Finalement, une diminution des performances en lien avec l'exposition sham ayant probablement eu lieu par hasard peut expliquer les effets apparents des champs électromagnétiques, en l'absence d'autres différences parmi les groupes hypersensibles (exposition réelle) et contrôles (exposition réelle, exposition sham) [32]. ...
Most of clinical studies on radiofrequency electromagnetic fields (RF) were directed at mobile phone-related exposures, usually at the level of the head, at their effect on some physiological functions including sleep, brain electrical activity (EEG), cognitive processes, brain vascularisation, and more generally on the cardiovascular and endocrine systems. They were frequently carried out on healthy adults. Effects on the amplitude of EEG alpha waves, mainly during sleep, look reproducible. It would however be important to define more precisely whether and how the absence of electromagnetic disturbance between RF exposure and the recording systems is checked. No consensus arises about cognitive effects. Some effects on cerebral vascularisation need complementary work.
... The absence of an effect of RF exposure on ANS activity, CFFT, reaction time or short-term memory in subjects with and without MPrelated symptoms are in line with most previous findings, although EEG changes and improved cognitive performance during RF exposure have recently been reported [27,39,50,80,81]. Wiholm et al. [81] reported enhanced spatial memory during exposure in subjects with MP-related pain or discomfort in the head, but not in control subjects. ...
... The absence of an effect of RF exposure on ANS activity, CFFT, reaction time or short-term memory in subjects with and without MPrelated symptoms are in line with most previous findings, although EEG changes and improved cognitive performance during RF exposure have recently been reported [27,39,50,80,81]. Wiholm et al. [81] reported enhanced spatial memory during exposure in subjects with MP-related pain or discomfort in the head, but not in control subjects. In Study I, an improvement in cognitive function was found among the MP subjects, but not among the control subjects; however, as the change was associated only with the number of performed tests and not with exposure condition, the finding was considered a practice effect. ...
... Une méta-analyse conduite sur 10 études [24] concernant les effets des signaux GSM sur les fonctions d'attention et de mémoire révélait une réduction du TR dans les tâches de soustraction ( 0,09, 95% CI: -0,16 to -0,02), du RT dans le test « 0-back target » ( 0,04, 95% CI: -0,06 à -0,02). Wiholm et al. [33] ont rapporté que les performances de navigation virtuelle chez un groupe de sujets hypersensibles étaient améliorées à la suite d'une exposition réelle. Cependant, un certain nombre d'éléments limitants dans les expérimentations ou l'interprétation des résultats ne permettent pas de conclure à un effet facilitateur des champs électromagnétiques RF sur la cognition. ...
... De même, malgré des tendances, les TR dans les tâches simples (P < 0,026) et de soustraction (P < 0,044) n'ont pas atteint la significativité statistique après correction en lien avec les tests multiples (14 tests) [26,27]. Finalement, une diminution des performances en lien avec l'exposition sham ayant probablement eu lieu par hasard peut expliquer les effets apparents des champs électromagnétiques, en l'absence d'autres différences parmi les groupes hypersensibles (exposition réelle) et contrôles (exposition réelle, exposition sham) [33]. En réponse à ces faiblesses dans les protocoles et les analyses, des ajustements ont été proposés. ...
... [16][17][18] Though less common, there are studies showing a beneficial effect on cognitive processing with the use of mobile phones. [19,20] Currently, there is little epidemiological evidence indicating that the mobile phone use causes adverse health effects. [21] Some previous studies have been done on "the EEG changes due to experimentally induced 3G mobile phone radiation," [22,23] but further studies are required for determining whether or not the duration of the exposure to radiation is related to effects, if any, on the brain. ...
... This is in contrast to some of the previous studies, which conclude that there is little epidemiological evidence indicating that the use of mobile phones causes adverse health effects. [20] All the study subjects were personally interviewed with regard to the amount of daily cell phone usage and any side effects of cell phone use as well as the adverse effects they experienced following the experimental application of mobile phone. This is a major strength of this study. ...
Background: Electromagnetic fields (EMFs) emitted by cellular telephones may cause neurological ill
effects like cognitive dysfunction, emotional instability, and even brain tumors. Slowing of brain activity on
electroencephalography (EEG) has been shown. However, these findings need further validation.
Aims: EEG changes and adverse effects experienced following cell‑phone use were studied.
Settings and Design: The study was conducted in the Department of Neurology of a tertiary care university
hospital in India on North Indian students of the University, from August 2017 to October 2017.
Materials and Methods: Twenty‑one students underwent video‑EEG recording before and after application of
Samsung GT‑56312 dual SIM smart phone in switched off, switched on, and switched on mode with conversation.
Statistical Analysis Used: Average EEG frequencies and amplitudes were calculated for different brain
regions. Chi‑square tests and t‑tests were used for comparison between variables.
Results: The mean age of 7 (33.3%) male and 14 (66.7%) female subjects was 20.76 ± 1.48 years. The
average EEG frequencies following mobile phone application with conversation were higher and the amplitudes
lower than the baseline values. Frequencies were greater on the right side. Slow waves were detected in the
frontal region in 38.1%, in the parietal region in 33.3%, in the occipital and temporal region in 19.1%; and,
generalized slow waves were seen in 9.5% students. During the experiment, 23.8% experienced headache,
19% experienced irritation, and 9.5% felt drowsy. Headache and loss of concentration (33.3%), sleep
disturbances (28.6%), and fatigue (19%) were frequent in daily life.
Conclusions: Experimental application of mobile phones may lead to some EEG changes and certain ill
effects on the well‑being. Hence, prolonged use of these gadgets warrants caution.
... В двух исследованиях авторами наблюдалось позитивное воздействие фактора: когнитивные функции, в чаа стности память, улучшились [5,13]. Однако многие авторы получили данные о негативном воздействии на когнитивные функции мышей, в том числе и на память [2,12,28,35]. Более ранние исследования преимущественно подтверждают отрицательное влияние излучения МТ на когнитивные функции животных. ...
This article gives a review of major experimental studies devoted to the effect of mobile phone electromagnetic emission on brain. The most relevant and fundamental studies were reviewed. Both positive and negative results were analyzed to give a straight answer, if mobile phone emission effects brain electrophysiology, cognitive function, subjective symptoms and blood-brain barrier permeability.
... Though some epidemiologic investigation was performed several decades ago on RF in occupational situations, in common, the effects of RF in humans are an emergent topic of investigation, and most investigations are recent or not yet published. Furthermore, even though the results of investigations of smartphone risks have received widespread public concentration, their understanding is not straightforward because of methodologic complexities [26][27][28][29][30][31][32][33][34] . ...
In analyzing the near field for a device, such as a mobile phone used in close proximity to tissues, it is difficult to predict the electromagnetic field (EMF) and other characteristics, since certain parts of the mobile phone scatter and reflect the EMF. Moreover, the absorption of EMF in the lossy tissues mitigates as the radio frequency (RF) energy is absorbed by the tissue. In order to minimize the heating effect on human tissue caused by this absorption of RF energy by the human body, all communications equipment (CE) must comply with the guidelines that established the maximum power output of devices. Though RF emissions from CE are carefully measured, the probability exists that the RF characteristics are reformed somewhat when tissue that illuminated by RF energy embedded with implant, thereby increasing the specific absorption rate (SAR). The SAR is the fundamental metric for specifying RF absorption by tissues and it can be calculated at any location in the tissue.
... The literature contains controversial reports on the effects of RF-EMW on, mitochondria, apoptosis pathway, heat shock proteins, free radical metabolism , cell differentiation, DNA damage and the plasma membrane [1,910111213141516. Among the effect of RF-EMW on various body organs, effect of RF-EMW on brain is the most researched area1718192021222324. Additionally, recent studies suggest that RF-EMW emitted from cell phones can reduce the fertilizing poten-tial of men [25]. ...
Hazardous health effects stemming from exposure to radiofrequency electromagnetic waves (RF-EMW) emitted from cell phones have been reported in the literature. However, the cellular target of RF-EMW is still controversial. This review identifies the plasma membrane as a target of RF-EMW. In addition, the effects of RF-EMW on plasma membrane structures (i.e. NADH oxidase, phosphatidylserine, ornithine decarboxylase) and voltage-gated calcium channels are discussed. We explore the disturbance in reactive oxygen species (ROS) metabolism caused by RF-EMW and delineate NADH oxidase mediated ROS formation as playing a central role in oxidative stress (OS) due to cell phone radiation (with a focus on the male reproductive system). This review also addresses: 1) the controversial effects of RF-EMW on mammalian cells and sperm DNA as well as its effect on apoptosis, 2) epidemiological, in vivo animal and in vitro studies on the effect of RF-EMW on male reproductive system, and 3) finally, exposure assessment and dosimetry by computational biomodeling.
... In fact, not all provocation studies in EHS patients have resulted in negative findings, meaning that EMF exposure including RFR and ELF EMF exposure could be potential triggers of biological and clinical effects in such patients. For example, in their 2011 systematic review of 122 provocation studies, Rubin et al. [124] arbitrarily selected 29 single or doubleblind studies assessed as having respected the review's selection protocol (i.e., having used a correct methodology), and considered 5 of these studies [51,[131][132][133][134] as being reliably associated with positive effects following EMF versus sham exposure-meaning that in so called IEI-EMF patients, EMF could induce various objective physiological alterations, such as heart rate and/or blood pressure variability, altered papillary light reflex, reduced visual alteration and perception, altered electroencephalogram (EEG) during sleep and skin conductance modifications, etc. In comparison with sham exposure, symptomatic intolerance induction has also been reported, in a single EHS case double-blind procedure, to be caused by off-on or on-off field transition rather than the presence of EMF exposure itself, while the EHS patient had no perception of this exposure. ...
Clinical research aiming at objectively identifying and characterizing diseases via clinical observations and biological and radiological findings is a critical initial research step when establishing objective diagnostic criteria and treatments. Failure to first define such diagnostic criteria may lead research on pathogenesis and etiology to serious confounding biases and erroneous medical interpretations. This is particularly the case for electrohypersensitivity (EHS) and more particularly for the so-called “provocation tests”, which do not investigate the causal origin of EHS but rather the EHS-associated particular environmental intolerance state with hypersensitivity to man-made electromagnetic fields (EMF). However, because those tests depend on multiple EMF-associated physical and biological parameters and have been conducted in patients without having first defined EHS objectively and/or endpoints adequately, they cannot presently be considered to be valid pathogenesis research methodologies. Consequently, the negative results obtained by these tests do not preclude a role of EMF exposure as a symptomatic trigger in EHS patients. Moreover, there is no proof that EHS symptoms or EHS itself are caused by psychosomatic or nocebo effects. This international consensus report pleads for the acknowledgement of EHS as a distinct neuropathological disorder and for its inclusion in the WHO International Classification of Diseases.
... Also, evaluations of sleepiness before sleep were collected. Cognitive measures have been reported elsewhere [Wiholm et al., 2009]. ...
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.
... In translating our data into possible effects in humans, there is support by the finding that memory deficits occur following EMF exposure on volunteers during clinical studies [36]. ...
The effects of mobile phone electromagnetic fields (EMFs) were studied on a non-spatial memory task (Object Recognition Task - ORT) that requires entorhinal cortex function. The task was applied to three groups of mice Mus musculus C57BL/6 (exposed, sham-exposed and control) combined with 3 different radiation exposure protocols. In the first protocol designated "acute exposure", mice 45 days old (PND45 - postnatal day 45) were exposed to mobile phone (MP) radiation (SAR value 0.22W/kg) during the habituation, the training and the test sessions of the ORT, but not during the 10min inter-trial interval (ITI) where consolidation of stored object information takes place. On the second protocol designated "chronic exposure-I", the same mice were exposed for 17 days for 90min/per day starting at PND55 to the same MP radiation. ORT recognition memory was performed at PND72 with radiation present only during the ITI phase. In the third protocol designated "chronic exposure-II", mice continued to be exposed daily under the same conditions up to PND86 having received radiation for 31 days. One day later the ORT test was performed without irradiation present in any of the sessions. The ORT-derived discrimination indices in all three exposure protocols revealed a major effect on the "chronic exposure-I" suggesting a possible severe interaction of EMF with the consolidation phase of recognition memory processes. This may imply that the primary EMF target may be the information transfer pathway connecting the entorhinal-parahippocampal regions which participate in the ORT memory task.
... Some subjects who use mobile phones have reported incidences of headache, dizziness, or other types of discomfort or pain [141]. These symptomatic subjects were compared to non-symptomatic males and females in a virtual Morris water maze during left-head exposure to 884 MHz set to nondiscontinuous or discontinuous transmission modes with psSAR10 g of 1.95 and 0.23 W/kg, respectively. ...
This review focuses upon the past 8 years of research on hyperthermic effects on behavior. Heat stress and heat stoke become severe conditions when body temperatures exceed 40°C as this can lead to delirium, convulsions, coma, and death. The animal literature indicates that hyperthermia can increase glutamatergic and decrease GABAergic neurotransmission. Interestingly, µ-opiate receptor antagonists can attenuate the morphological and biochemical changes in brain, as well as, ameliorate some behavioral deficits induced by heart stress. In humans, heat stress can produce detrimental effects on motor and cognitive performance. Since most cognitive tasks require a motor response, some cognitive deficiencies may be attributed to decreased motor performance. Although hyperthermia may exert more deleterious effects on complex than simple cognitive tasks, systematic studies are needed to examine the effects of different levels and durations of hyperthermia (irrespective of dehydration) on cognition. Additionally, body temperatures should be carefully monitored where controls are run for baseline or brief exposures to a hyperthermic environment. Acute radiofrequency exposure can disrupt behavior when body temperatures increase >1°C with whole body SAR between 3.2-8.4 W/kg and time-averaged power densities at 8-140 mW/cm(2). Effects of lower levels of radiation are conflicting and some experiments fail to replicate even with the original investigators. This suggests either that brief exposure to the radiation is at a threshold where some individuals are affected while others are not, or that these levels are innocuous. Nevertheless, thermal changes appear to account for almost all of the behavioral effects reported.
... People using cell phones are susceptible to high blood pressure and other symptoms such as headaches and fatigue [26,27]. There have been various studies into the connection between mobile phones and memory and the results were confusing and sometime contradictory [28][29][30]. ...
The use of cellular technology is overwhelming our lives these days. Global System for Mobile communications (GSM) waves -the basis of cellular technology - are high frequency, high energy electromagnetic waves that may pause as a threat to man. The current work studies the effect of such waves on two types of skeletal muscles, the slow and fast twitching muscles in adult male rats. The activity, morphology, and structure of the affected muscles are studied and analyzed against control. Experiments evaluate changes in body weight, muscle mass, water and protein content, total RNA concentration, testosterone level, and Myosin Heavy Chain (MHC) isoforms expression. Our results show that in both muscles, there are changes in the distribution of muscles proteins and in the percentage of MHC isoforms suggesting that the GSM antenna relay affects the plasticity of skeletal muscle fiber by transforming slow type to faster one.
... Most of the previous studies, however, focused on the adverse effects of exposure to mobile phone EMFs. For example, a considerable number of studies dealt with the potential influences of mobile phones with the former Global System for Mobile Communications (GSM) technology on self-reported symptoms and sensations like headache, migraine, sleep disturbances, forgetfulness, and skin irritation in healthy and/or sensitive individuals [Koivisto et al., 2001;Balikci et al., 2005;Arnetz et al., 2007Arnetz et al., , 2009Cinel et al., 2008;Hillert et al., 2008;Wiholm et al., 2009]. Findings from these studies do not consistently suggest an increased level of adverse subjective symptoms relating to mobile phone-induced EMF exposure. ...
One of the most frequently investigated effects of radiofrequency electromagnetic fields (RF EMFs) on the behavior of complex biological systems is pain sensitivity. Despite the growing body of evidence of EMF-induced changes in pain sensation, there is no currently accepted experimental protocol for such provocation studies for the healthy human population. In the present study, therefore, we tested the effects of third generation Universal Mobile Telecommunications System (UMTS) RF EMF exposure on the thermal pain threshold (TPT) measured on the surface of the fingers of 20 young adult volunteers. The protocol was initially validated with a topical capsaicin treatment. The exposure time was 30 min and the genuine (or sham) signal was applied to the head through a patch antenna, where RF EMF specific absorption rate (SAR) values were controlled and kept constant at a level of 1.75 W/kg. Data were obtained using randomized, placebo-controlled trials in a double-blind manner. Subjective pain ratings were tested blockwise on a visual analogue rating scale (VAS). Compared to the control and sham conditions, the results provide evidence for intact TPT but a reduced desensitization effect between repeated stimulations within the individual blocks of trials, observable only on the contralateral side for the genuine UMTS exposure. Subjective pain perception (VAS) data indicated marginally decreased overall pain ratings in the genuine exposure condition only. The present results provide pioneering information about human pain sensation in relation to RF EMF exposure and thus may contribute to cover the existing gap between safety research and applied biomedical science targeting the potential biological effects of environmental RF EMFs. Bioelectromagnetics © 2013 Wiley Periodicals, Inc.
... Two publications [6,7] with funding by the telecommunication industry reported that their university had acted as a firewall between them and their sponsors. In these studies, funders might have had an influence on the design of the study when deciding upon granting funds for a study, but most likely not on the data collection, interpretation and reporting process. ...
A previous review showed that among 59 studies published in 1995–2005, industry-funded studies were least likely to report effects of controlled exposure to mobile phone radiation on health-related outcomes. We updated literature searches in 2005–2009 and extracted data on funding, conflicts of interest and results. Of 75 additional studies 12% were industry-funded, 44% had public and 19% mixed funding; funding was unclear in 25%. Previous findings were confirmed: industry-sponsored studies were least likely to report results suggesting effects. Interestingly, the proportion of studies indicating effects declined in 1995–2009, regardless of funding source. Source of funding and conflicts of interest are important in this field of research.RésuméUne précédente revue a montré que, parmi 59 études publiées entre 1995 et 2005, les études financées par l'industrie étaient moins susceptibles de mettre en évidence des effets liés à la santé de l'exposition contrôlée aux émissions radiofréquences de type téléphone mobile. Nous avons mis à jour notre base à partir de la littérature publiée entre 2005 et 2009 et extrait les informations concernant le financement, les conflits d'intérêts et les résultats. Parmi 75 nouvelles études, 12%12% ont un financement de l'industrie, 44%44% un financement public et 19%19% un financement mixte public-privé. Les résultats précédents ont été confirmés : les études financées par l'industrie sont moins susceptibles de suggérer des effets sur la santé. Autre fait intéressant, la proportion d'études indiquant des effets a diminué entre 1995 et 2009, quelque soit le mode de financement. La source de financement et les conflits d'intérêt sont importants à prendre en compte dans ce domaine de recherche.
... The decrease in the intensity of the effect at lower level about four times is much less than Trunk et al. 20132.18 Lv, Su et al. 2014Lv, Chen et al. 20142-1.5 Croft et al. 2010Leung et al. 2011;Lowden et al. 2011;Vecsei et al. 2013;Sauter et al. 2015;Lustenberger et al. 2015;Verrender et al. 2016;Yang et al. 2017;Vecsei et al. 2018;Dalecki et al. 2018;Loughran et al. 2019;Lowden et al. 2019Stefanics et al. 2008Croft et al. 2010;Riddervold et al. 2010;Danker-Hopfe et al. 2011;Nakatani-Enomoto et al. 2013Trunk et al. 2015;Eggert et al. 2015 1.5-1 Hung et al. 2007;Krause et al. 2007;Luria et al. 2009;Wiholm et al. 2009;Lustenberger et al. 2015;Verrender et al. 2016;Yang et al. 2017;Dalecki et al. 2018;Loughran et al. 2019Fritzer et al. 2007Haarala et al. 2007;Krause et al. 2007;Kleinlogel et al. 2008aKleinlogel et al. , 2008bHillert et al. 2008;Kwon et al. 2009Kwon et al. , 2010Loughran et al. 2013 1-0.5 Bardasano et al. 2007;Curcio et al. 2008;Croft et al. 2008;de Tommaso et al. 2009;Curcio et al. 2009;Croft et al. 2010;Vecchio et al. 2010;Leung et al. 2011;Ghosn et al. 2015;Curcio et al. 20150.5-0.1 Bachmann, Tomson, et al. 2007Bachmann et al. 2018: Hung et al. 2007Hinrikus Bachmann, Lass, Tomson, et al. 2008;Hinrikus, Bachmann, Lass, Karai, et al. 2008;Hinrikus et al. 2009;Suhhova et al. 2009;Lustenberger et al. 2013;Suhhova et al. 2013;Hinrikus et al. 2017Regel, Gottselig, et al. 2007Eltiti et al. 2009 <0 expected according to the decrease of SAR (100 times). The relative decrease of the effect is rather close to the change in field strength (10 times). ...
Purpose: This review aims to estimate the threshold of radiofrequency electromagnetic field (RF EMF) effects on human brain based on analyses of published research results. To clarify the threshold of the RF EMF effects, two approaches have been applied: 1) the analyses of restrictions in sensitivity for different steps of the physical model of low-level RF EMF mechanism and 2) the analyses of experimental data to clarify the dependence of the RF EMF effect on exposure level based on the results of published original neurophysiological and behavioral human studies for 15 years 2007-2021.
Conclusions: The analyses of the physical model of non-thermal mechanisms of RF EMF effect leads to conclusion that no principal threshold of the effect can be determined. According to the review of experimental data, the rate of detected RF EMF effects is 76.7% in resting EEG studies, 41.7% in sleep EEG and 38.5% in behavioral studies. The changes in EEG probably appear earlier than alterations in behavior become evident. The lowest level of RF EMF at which the effect in EEG was detected is 2.45 V/m (SAR =0.003 W/kg). There is a preliminary indication that the dependence of the effect on the level of exposure follows rather field strength than SAR alterations. However, no sufficient data are available for clarifying linearity-nonlinearity of the dependence of effect on the level of RF EMF. The finding that only part of people are sensitive to RF EMF exposure can be related to immunity to radiation or hypersensitivity. The changes in EEG caused by RF EMF appeared similar in the majority of analyzed studies and similar to these in depression. The possible causal relationship between RF EMF effect and depression among young people is highly important problem.
... Hung et al. (2007) reported that GSM in "talk-mode" delayed sleep latency. Recently, Wiholm et al. (2009) found that subjects with self-reported symptoms who were performing a virtual spatial navigation test scored better after exposure to 884 MHz at an average SAR of 1.4 W/kg. Augner et al. (2009) studied psychological symptoms (good mood, alertness, calmness) in subjects exposed to GSM base station signals for 50 minutes. ...
The purpose of this opinion is to update the SCENIHR opinion of 21 March 2007 in the
light of newly available information, and to provide a methodological framework and
corresponding guidelines to evaluate available scientific evidence in order to ensure the
best possible quality for risk assessment.
1. Update
Radio frequency fields (RF fields)
It is concluded from three independent lines of evidence (epidemiological, animal and in
vitro studies) that exposure to RF fields is unlikely to lead to an increase in cancer in
humans. However, as the widespread duration of exposure of humans to RF fields from
mobile phones is shorter than the induction time of some cancers, further studies are
required to identify whether considerably longer-term (well beyond ten years) human
exposure to such phones might pose some cancer risk.
Regarding non-carcinogenic outcomes, several studies were performed on subjects
reporting subjective symptoms. In the previous opinion, it was concluded that scientific
studies had failed to provide support for a relationship between RF exposure and selfreported
symptoms. Although an association between RF exposure and single symptoms
was indicated in some new studies, taken together, there is a lack of consistency in the
findings. Therefore, the conclusion that scientific studies have failed to provide support
for an effect of RF fields on self-reported symptoms still holds. Scientific studies have
indicated that a nocebo effect (an adverse non-specific effect that is caused by
expectation or belief that something is harmful) may play a role in symptom formation.
As in the previous opinion, there is no evidence supporting that individuals, including
those attributing symptoms to RF exposure, are able to detect RF fields. There is some
evidence that RF fields can influence EEG patterns and sleep in humans. However, the
health relevance is uncertain and mechanistic explanation is lacking. Further
investigation of these effects is needed. Other studies on functions/aspects of the
nervous system, such as cognitive functions, sensory functions, structural stability, and
cellular responses show no or no consistent effects.
Recent studies have not shown effects from RF fields on human or animal reproduction
and development. No new data have appeared that indicate any other effects on human
health.
From the risk assessment perspective it is important to recognise that information on
possible effects caused by RF fields in children is limited. Furthermore, there is a lack of
information on diseases other than those discussed in this report.
Intermediate frequency fields (IF fields)
Occupational exposure to IF fields in certain areas is considerably higher than exposure
to the general public. However, very little research on IF and health risks in occupational
settings or for the general public have been presented since the previous opinion, and no
epidemiological studies have appeared. Consequently, the data are still too limited for an
appropriate risk assessment.
In view of the increasing occupational exposure to IF among workers in e.g. security,
shops, and certain industries it is important that research in this area is given priority.
Extremely low frequency fields (ELF fields)
The few new epidemiological and animal studies that have addressed ELF exposure and
cancer do not change the previous assessment that ELF magnetic fields are a possible
carcinogen and might contribute to an increase in childhood leukaemia. At present, in
vitro studies did not provide a mechanistic explanation of this epidemiological finding.
No new studies support a causal relationship between ELF fields and self-reported
symptoms.
Health Effects of Exposure to EMF
5
New epidemiological studies indicate a possible increase in Alzheimer's disease arising
from exposure to ELF. Further epidemiological and laboratory investigations of this
observation are needed.
Recent animal studies provided an indication for effects on the nervous system at flux
densities from 0.10-1.0 mT. However, there are still inconsistencies in the data, and no
definite conclusions can be drawn concerning human health effects.
Very few recent in vitro studies have investigated effects from ELF fields on diseases
other than cancer and those available have very little relevance. There is a need for
hypothesis-based in vitro studies to examine specific diseases.
It is notable that in vivo and in vitro studies show effects at exposure levels (from 0.10
mT and above) to ELF fields that are considerably higher than the levels encountered in
the epidemiological studies (μT-levels) which showed an association between exposure
and diseases such as childhood leukaemia and Alzheimer's disease. This warrants further
investigation.
Static fields
Although a fair number of studies have been published since the last opinion, the
conclusion drawn there stands: there is still a lack of adequate data for a proper risk
assessment of static magnetic fields. More research is necessary, especially to clarify the
many mixed and sometimes contradictory results.
Short term effects have been observed primarily on sensory functions for acute
exposure. However, there is no consistent evidence for sustained adverse health effects
from short term exposure up to several teslas.
Environmental effects
The current database is inadequate for the purposes of the assessment of possible risks
due to environmental exposure to RF, IF and ELF.
Research recommendations
The scientific rationale has identified a number of areas characterised by insufficient and
contradictory information regarding possible health associated effects from the various
frequency bands of the EMF spectrum. It is recommended that certain knowledge gaps
are filled.
2. Methodological Framework
The SCENIHR is asked to provide a methodological framework and corresponding
guidelines to evaluate available scientific evidence in order to ensure the best possible
quality for risk assessment. The subject is covered in detail in chapter 3.8 of the opinion.
The present opinion provides a methodological framework and guidelines as:
- a general outline of criteria used for making EMF health risk assessment
- a description of the work procedure leading to the overall evaluation
- a specialised section where characteristics and quality criteria regarding dosimetry
and exposure assessment, epidemiology, human laboratory studies, in vivo
studies, and in vitro studies are presented.
... Sienkiewicz studied the effect of an electromagnetic field at 900 MHz on spatial learning in rats using an eight-armed radial maze and found that placing the rats in this field for 45 minutes each day for 10 consecutive days had no effects on their memories (20). However, at these frequency bands, cell phone waves affect human memory (21,22) and some of the studies have used water and radial mazes at a frequency of 2 450 MHz (7,8,23). Lai et al. (7) studied the effect of 45 minutes of irradiation with 2 450 MHz of electromagnetic waves for 10 days on rats' memory using a 12-armed radial maze and found that the radiation affected memory in the hippocampal region of the brain. ...
Objectives
Despite two decades of using mobile phone, the biological effects of electromagnetic radiation remain controversial. The study was conducted to determine the effect of mobile phone waves on anxiety-like behaviors in male rats.
Methods
A total number of 80 male naive rats were, randomly, divided into eight groups (Control, 900, 1 800, and 2 100 MHz exposure). The acute and chronic effects of mobile phone radiation on the anxiety profile was compared considering a 45-min session and seven sessions of radiation (45 min/day) using the elevated plus-maze (EPM) in rats. The number of rats entering the open and closed arms and their duration of stay in each of the arms were assessed. To estimate the oxidative stress, Superoxide Dismutase level in the blood serum was evaluated.
Results
The results obtained in the EPM showed no significant differences among the groups after acute exposure to mobile phone radiation (P > 0.05). No significant differences were observed among the groups in terms of their serum superoxide dismutase level (P > 0.05).
Conclusions
Short time mobile phone radiation had no effect on anxiety-like behaviors and serum enzyme activity; this may be due to low tissue irritation during acute exposure to mobile phone waves.
... Sienkiewicz studied the effect of an electromagnetic field at 900 MHz on spatial learning in rats using an eight-armed radial maze and found that placing the rats in this field for 45 minutes each day for 10 consecutive days had no effects on their memories (20). However, at these frequency bands, cell phone waves affect human memory (21,22) and some of the studies have used water and radial mazes at a frequency of 2 450 MHz (7,8,23). Lai et al. (7) studied the effect of 45 minutes of irradiation with 2 450 MHz of electromagnetic waves for 10 days on rats' memory using a 12-armed radial maze and found that the radiation affected memory in the hippocampal region of the brain. ...
Abstract
Objectives: Despite two decades of using mobile phone, the biological effects of electromagnetic radiation remain controversial. The study was conducted to determine the effect of mobile phone waves on anxiety-like behaviors in male rats.
Methods: 80 male naive rats randomly divided in eight groups (Control, 900, 1800 and 2100 MHz exposure); 4 group with one (45 minute) and another's with seven sessions of mobile phone radiation. Anxiety-like behaviors were tested in the elevated plus-maze (EPM). The number of rats entering the open and closed arms and their duration of stay in each of the arms and Superoxide Dismutase level in the rats’ blood serum were assessed.
Results: The results obtained in the EPM showed no significant differences between the groups after acute exposure to mobile phone irradiation (P>0.05). No significant differences were observed between the groups in terms of their serum Superoxide Dismutase level (P>0.05).
Conclusions: Short time mobile phone radiation had no effect on anxiety-like behaviors and serum enzyme activity; this may be due to the low tissue irritation during acute irradiation by mobile phone waves.
... Among the effects of EMR on various body organs, the effect on the brain is the most important (Cardis et al., 2008;Eberhardt et al., 2008;Hardell and Sage, 2008;O'Keefe, 2008;Sokolovic et al., 2008;Wiholm et al., 2009). The study of Schönborn et al. (1998) showed that the adult human head absorbs 80% of the radiation emitted by a cellular phone. ...
ABSTRACT
Electromagnetic radiation (EMR) of cellular phones may affect biological systems by increasing
free radicals and changing the antioxidant defense systems of tissues, eventually leading to
oxidative stress. Green tea has recently attracted significant attention due to its health benefits
in a variety of disorders, ranging from cancer to weight loss. Thus, the aim of the present study
was to investigate the effect of EMR (frequency 900 MHz modulated at 217 Hz, power density 0.02
mW/cm2, SAR 1.245 W/kg) on different oxidative stress parameters in the hippocampus and
striatum of adult rats. This study also extends to evaluate the therapeutic effect of green tea
mega EGCG on the previous parameters in animals exposed to EMR after and during EMR
exposure. The experimental animals were divided into four groups: EMR-exposed animals, animals
treated with green tea mega EGCG after 2 months of EMR exposure, animals treated with green
tea mega EGCG during EMR exposure and control animals. EMR exposure resulted in oxidative
stress in the hippocampus and striatum as evident from the disturbances in oxidant and antioxidant
parameters. Co-administration of green tea mega EGCG at the beginning of EMR exposure
for 2 and 3 months had more beneficial effect against EMR-induced oxidative stress than oral
administration of green tea mega EGCG after 2 months of exposure. This recommends the use of
green tea before any stressor to attenuate the state of oxidative stress and stimulate the
antioxidant mechanism of the brain.
... Numerous studies are devoted to depicting the relationship between radio waves and alterations of biological and behavioural functions or their ecological effects (for review, see Cucurachi et al. 2013). Although a direct relationship has not been established between radio wave exposure and health problems (Krewski et al. 2007;Vanderstraetan and Verschaeve 2008), behavioural and spatial memory disorders in humans (D'Andrea et al. 2003;Wiholm et al. 2009) and orientation disorders in honeybees and birds (Warnke 2007) have been suspected and a negative effect of radio waves on the in-hive behaviour and homing flight of honeybees has been reported (Harst et al. 2006;Kimmel et al. 2007). Cell phone radiations were suspected of affecting the reproductive capacity of Drosophila (Panagopoulos et al. 2004) and the egg laying rate of the honeybees' queen (Sharma and Kumar 2010) and inducing the worker piping signal in the hive (Favre 2011). ...
Recent studies succeeded in developing a method to automatically record honeybees going in and out of the hive. Honeybees were individualized with radio frequency identification (RFID) tags glued onto their dorsal surface and detected at the hive entrance by readers emitting high-frequency (HF) radio waves. In this work we search for a possible adverse effect of HF on honeybees’ survival. Eight-day-old honeybees were exposed to HF (13.56 MHz) or ultra-high-frequency (UHF, 868 MHz) radio waves for 2 h split into ON and OFF periods. The ON/OFF ratio was 1:3 (OFF duration 3, 90, 180, 370 and 360 s) or 1:5 (OFF duration 300 s). Dead individuals were counted every day, and the cumulative mortality rates of exposed and non-exposed honeybees were compared 7 days after exposure. Out of the five experimental conditions, we observed an increase in mortality in two conditions, once after HF and once after UHF exposure, with OFF duration of 5 min or more. We then recommend limiting exposure of honeybees to radio waves to less than 2 h per day, and we conclude that the RFID parameters, like those we used in the field for monitoring hive activity, present no adverse effects for honeybees.
... D autre part, Smythe et Costall(Smythe et Costall, 2003) ont comparé seulement deux groupes avec l'exposition réelle et fictive parce que la comparaison initiale, y compris une condition ''sans téléphone'', n'a pas révélé de résultats significatifs. Quant à eux, Wiholm et al.(Wiholm et al., 2009) ont trouvé que les performances de navigation virtuelle d'un groupe de personnes hypersensibles ont été améliorées après l'exposition réelle, mais la performance a été réellement altérée après l exposition fictive, sans autre différence entre les groupes d'hypersensibles et de non-hypersensibles (contrôle). Un tel résultat (altération des performances due à une exposition fictive) semble avoir eu lieu par hasard.En résumé, les études comportementales précoces ont rapporté des effetssignificatifs de l'exposition au téléphone mobile sur les fonctions d attention et de mémoire (amélioration des performances cognitives), qui semblaient avoir eu lieu par hasard en raison de comparaisons multiples. ...
Many concerns are now expressed about harmfulness of radiofrequency fields emitted by mobile phones on health. Since the head and the skin are the most exposed organs, cerebral circulation, cutaneous microcirculation of the face and brain's electrical activity are specifically involved. To this purpose, we conducted two studies in healthy adult volunteers to assess cerebral blood flow velocity in middle cerebral arteries by transcranial Doppler and skin micro blood flow by laser Doppler flowmeter in the first one, and to detect any possible changes in brain electrical activity by electroencephalography in the second one. The radiofrequency exposure was carried out by two commercial mobile phones, a 'real' phone which emitted spectrum and heat at the same time and the other 'sham' phone which heated only without emission. The first study showed no effect of radiofrequencies on cerebral blood flow velocity in the middle cerebral arteries, however, a significant increase in skin micro blood flow during 'real' versus 'sham' exposure was observed while skin temperature increase was similar in both exposure sessions 'sham' and 'real'. Brain's electrical activity showed a decrease in the alpha frequency band (8-12 Hz) spectral power during and after 'real' versus 'sham' exposure.
... Another study has shown that there is a significant effect of mobile phone use on cognition in young adolescents (2) . There are various studies which show the effect of mobile phone use with media multitasking (3) , use of social networking sites (4) on spatial memory (5) and cognition (3,4) . ...
Background: The increasing use of mobile phones in the present scenario and its adverse effects on human health is the topic of attention. Material and Method: 50 healthy medical students of first Professional MBBS of Santosh medical college were randomly selected for the procedure. A computerized group of 15 words were presented to the participants and they were asked to reproduce it. Statistical Analysis: Data was analysed by SPSS version 22.0 and p <0.05 was considered as significant. Result: Our study result shows that use of mobile phones has significant negative effect on working memory. Discussion: We conclude that use of mobile phone leads to impairment of working memory and cognition in medical students. It is therefore recommended that duration of use of mobile phones should be done in intervals rather than continuously.
This chapter tries to ascertain whether mobile phones (and mobile phone-like exposures) impact on health, with the premise being that, if they do, then this would not only illuminate a hidden danger, but also necessitate a search for a new biophysical mechanism. Electromagnetic energy travels as waves, which, depending on the particular frequency, can interact with the body in different ways. Health effects from the low-level exposures from mobile phones are not predicted because the resultant heating is too low. The body engages in a tightly regulated cycle of physiological changes that induce and promote effective sleep. These can be measured in terms of indices of sleep architecture, such as sleep duration, and the underlying electroencephalograph (EEG) changes that accompany these stages. The EEG power spectrum can be resolved into relatively discrete frequency bands, which represent the sum of a range of distinct cognitive processes.
Objective: The aim of this study was to investigate the histopathological and ultrastructural prenatal effects of mobile phone microwave radiation on mice liver.
Materials and methods: Pregnant mice were divided into three groups of 10 animals each. Group one (G1) was the control group with mice unexposed to mobile phone. Group two (G2) mice were exposed for half-hour every day during the gestational period with the cell phone in answering state. Group three (G3) mice were exposed during the gestational period for 1 h every day with the cell phone in answering state and for 12 h while the cell phone was in standby state. The microwave radiation produced by mobile phones operated at a microwave frequency range of 900–1800 MHz. Mice fetuses were examined and then killed with an overdose of ether. Liver biopsies were prepared for histopathological and ultrastructural examinations.
Results: The mean body weight and length of fetuses of G3 showed a statistically significant decrease compared with G1 (P<0.05). Congestion of the central vein and dilation of hepatic blood sinusoids were the most frequent histopathological findings. The ultrastructural results were apparent in G3 in the form of dilated rough endoplasmic reticulum, loss of mitochondrial cristae and pleomorphic mitochondria, mitochondrial swelling and fragmentation, hepatocytic vaculations, nuclear inclusions, and inflammatory cell infiltration in the periportal areas, of mainly lymphocytes. The results of this study showed a significant reduction in the average body weight and length of fetuses of G2 and G3.
Conclusion: The ultrastructural damage observed in the examined specimens shows the hepatocellular injuries and consequent systemic impairment of body functions.
During recent years, a large number of studies on the effects of electromagnetic fields emitted by cellular mobile phones on human cognitive performance have been carried out. However, the results have been ambiguous. We carried out the current meta-analysis in order to investigate the impact of electromagnetic fields emitted by mobile phones on human cognition. Seventeen studies were included in the meta-analysis as they fulfill several requirements such as single- or double-blind experimental study design, and documentation of means and standard deviations of dependent variables. The meta-analysis was carried out as a group comparison between exposed and non-exposed subjects. No significant effects of electromagnetic fields emitted by Global System for Mobile Communications (GSM) and Universal Mobile Telecommunications System (UMTS) mobile phones were found. Cognitive abilities seem to be neither impaired nor facilitated. Results of the meta-analysis suggest that a substantial short-term impact of high frequency electromagnetic fields emitted by mobile phones on cognitive performance can essentially be ruled out. Bioelectromagnetics. © 2011 Wiley-Liss, Inc.
In this study, we investigated the effects of mobile phone radiation on spatial learning, reference memory, and morphology in related brain regions. After the near-field radiation (0.52-1.08 W/kg) was delivered to 8-week-old Wistar rats 2 hours per day for 1 month, behavioral changes were examined using the Morris water maze. Compared with the sham-irradiated rats, the irradiated rats exhibited impaired performance. Morphological changes were investigated by examining synaptic ultrastructural changes in the hippocampus. Using the physical dissector technique, the number of pyramidal neurons, the synaptic profiles, and the length of postsynaptic densities in the CA1 region were quantified stereologically. The morphological changes included mitochondrial degenerations, fewer synapses, and shorter postsynaptic densities in the radiated rats. These findings indicate that mobile phone radiation can significantly impair spatial learning and reference memory and induce morphological changes in the hippocampal CA1 region.
For the last two decades, a large number of studies have investigated the effects of mobile phone radiation on the human brain and cognition using behavioral or neurophysiological measurements. This review evaluated previous findings with respect to study design and data analysis. Provocation studies found no evidence of subjective symptoms attributed to mobile phone radiation, suggesting psychological reasons for inducing such symptoms in hypersensitive people. Behavioral studies previously reported improved cognitive performance under exposure, but it was likely to have occurred by chance due to multiple comparisons. Recent behavioral studies and replication studies with more conservative statistics found no significant effects compared with original studies. Neurophysiological studies found no significant effects on cochlear and brainstem auditory processing, but only inconsistent results on spontaneous and evoked brain electrical activity. The inconsistent findings suggest possible false positives due to multiple comparisons and thus replication is needed. Other approaches such as brain hemodynamic response measurements are promising but the findings are few and not yet conclusive. Rigorous study design and data analysis considering multiple comparisons and effect size are required to reduce controversy in this important field of research.
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.
Part of the population considers themselves as sensitive to the man-made electromagnetic radiation (EMF) emitted by powerlines, electric wiring, electric home appliance and the wireless communication devices and networks. Sensitivity is characterized by a broad variety of non-specific symptoms that the sensitive people claim to experience when exposed to EMF. While the experienced symptoms are currently considered as a real life impairment, the factor causing these symptoms remains unclear. So far, scientists were unable to find causality link between symptoms experienced by sensitive persons and the exposures to EMF. However, as presented in this review, the executed to-date scientific studies, examining sensitivity to EMF, are of poor quality to find the link between EMF exposures and sensitivity symptoms of some people. It is logical to consider that the sensitivity to EMF exists but the scientific methodology used to find it is of insufficient quality. It is time to drop out psychology driven provocation studies that ask about feelings-based non-specific symptoms experienced by volunteers under EMF exposure. Such research approach produces only subjective and therefore highly unreliable data that is insufficient to prove, or to disprove, causality link between EHS and EMF. There is a need for a new direction in studying sensitivity to EMF. The basis for it is the notion of a commonly known phenomenon of individual sensitivity, where individuals' responses to EMF depend on the genetic and epigenetic properties of the individual. It is proposed here that new studies, combining provocation approach, where volunteers are exposed to EMF, and high-throughput technologies of transcriptomics and proteomics are used to generate objective data, detecting molecular level biochemical responses of human body to EMF.
The use of mobile phones is rapidly increasing all over the world. Few studies deal with the effect of electromagnetic radiation (EMR) on monoamine neurotransmitters in the different brain areas of adult rat.
The aim of the present study was to investigate the effect of EMR on the concentrations of dopamine (DA), norepinephrine (NE) and serotonin (5-HT) in the hippocampus, hypothalamus, midbrain and medulla oblongata of adult rats.
Adult rats were exposed daily to EMR (frequency 1800 MHz, specific absorption rate 0.843 W/kg, power density 0.02 mW/cm2, modulated at 217 Hz) and sacrificed after 1, 2 and 4 months of daily EMR exposure as well as after stopping EMR for 1 month (after 4 months of daily EMR exposure). Monoamines were determined by high performance liquid chromatography coupled with fluorescence detection (HPLC-FD) using their native properties.
The exposure to EMR resulted in significant changes in DA, NE and 5-HT in the four selected areas of adult rat brain.
The exposure of adult rats to EMR may cause disturbances in monoamine neurotransmitters and this may underlie many of the adverse effects reported after EMR including memory, learning, and stress.
As millimeter waves (MMWs) are being increasingly used in communications and military applications, their potential effects on biological tissue has become an important issue for scientific inquiry. Specifically, several MMW effects on the whole-nerve activity were reported, but the underlying neuronal changes remain unexplored. This study used slices of cortical tissue to evaluate the MMW effects on individual pyramidal neurons under conditions mimicking their in vivo environment. The applied levels of MMW power are three orders of magnitude below the existing safe limit for human exposure of 1 mW cm(-2). Surprisingly, even at these low power levels, MMWs were able to produce considerable changes in neuronal firing rate and plasma membrane properties. At the power density approaching 1 microW cm(-2), 1 min of MMW exposure reduced the firing rate to one third of the pre-exposure level in four out of eight examined neurons. The width of the action potentials was narrowed by MMW exposure to 17% of the baseline value and the membrane input resistance decreased to 54% of the baseline value across all neurons. These effects were short lasting (2 min or less) and were accompanied by MMW-induced heating of the bath solution at 3 degrees C. Comparison of these results with previously published data on the effects of general bath heating of 10 degrees C indicated that MMW-induced effects cannot be fully attributed to heating and may involve specific MMW absorption by the tissue. Blocking of the intracellular Ca(2+)-mediated signaling did not significantly alter the MMW-induced neuronal responses suggesting that MMWs interacted directly with the neuronal plasma membrane. The presented results constitute the first demonstration of direct real-time monitoring of the impact of MMWs on nervous tissue at a microscopic scale. Implication of these findings for the therapeutic modulation of neuronal excitability is discussed.
Although official statistics challenge the effect of electromagnetic fields on
human health, it is often questioned because of the incontrovertible evidence of increased
incidence of various cancers and skull tumor emergence and development. Exposure to
radio frequency (RF), extremely low frequency (ELF) fields and microwave fields (MW)
by using more often mobile (GSM) and wireless phones and exposure to electromagnetic
fields created by communications antennas prove a causal link between exposure to
electromagnetic fields and various forms of cancers developed. Study of the interaction of
electromagnetic non-ionizing fields (EMF) and living matter and its possible biological
and health effects is currently one of the topics most discussed and controversial, not only
because of its purely scientific interest, but also with reference to its cultural, social and
economic implications
Purpose
The deployment of new 5G NR technology has significantly raised public concerns in possible negative effects on human health by radiofrequency electromagnetic fields (RF EMF). The current review is aimed to clarify the differences between possible health effects caused by the various generations of telecommunication technology, especially discussing and projecting possible health effects by 5G. The review of experimental studies on the human brain over the last fifteen years and the discussion on physical mechanisms and factors determining the dependence of the RF EMF effects on frequency and signal structure have been performed to discover and explain the possible distinctions between health effects by different telecommunication generations.
Conclusions
The human experimental studies on RF EMF effects on the human brain by 2G, 3G and 4G at frequencies from 450 to 2500 MHz were available for analyses. The search for publications indicated no human experimental studies by 5G nor at the RF EMF frequencies higher than 2500 MHz. The results of the current review demonstrate no consistent relationship between the character of RF EMF effects and parameters of exposure by different generations (2G, 3G, 4G) of telecommunication technology. At the RF EMF frequencies lower than 10 GHz, the impact of 5G NR FR1 should have no principal differences compared to the previous generations. The radio frequencies used in 5G are even higher and the penetration depths of the fields are smaller, therefore the effect is rather lower than at previous generations. At the RF EMF frequencies higher than 10 GHz, the mechanism of the effects might differ and the impact of 5G NR FR2 becomes unpredictable. Existing knowledge about the mechanism of RF EMF effects at millimeter waves lacks sufficient experimental data and theoretical models for reliable conclusions. The insufficient knowledge about the possible health effects at millimeter waves and the lack of in vivo experimental studies on 5G NR underline an urgent need for the theoretical and experimental investigations of health effects by 5G NR, especially by 5G NR FR2.
The neural basis of navigation by humans was investigated with functional neuroimaging of brain activity during navigation
in a familiar, yet complex virtual reality town. Activation of the right hippocampus was strongly associated with knowing
accurately where places were located and navigating accurately between them. Getting to those places quickly was strongly
associated with activation of the right caudate nucleus. These two right-side brain structures function in the context of
associated activity in right inferior parietal and bilateral medial parietal regions that support egocentric movement through
the virtual town, and activity in other left-side regions (hippocampus, frontal cortex) probably involved in nonspatial aspects
of navigation. These findings outline a network of brain areas that support navigation in humans and link the functions of
these regions to physiological observations in other mammals.
Electrophysiological studies have shown that single cells in the
hippocampus respond during spatial learning and
exploration1-4, some firing only when animals enter specific
and restricted areas of a familiar environment. Deficits in spatial
learning and memory are found after lesions of the hippocampus and its
extrinsic fibre connections5,6 following damage to the medial
septal nucleus which successfully disrupts the hippocampal theta
rhythm7, and in senescent rats which also show a correlated
reduction in synaptic enhancement on the perforant path input to the
hippocampus8. We now report, using a novel behavioural
procedure requiring search for a hidden goal, that, in addition to a
spatial discrimination impairment, total hippocampal lesions also cause
a profound and lasting placenavigational impairment that can be
dissociated from correlated motor, motivational and reinforcement
aspects of the procedure.
The hippocampus has been proposed as the site of neural representation of large-scale environmental space, based upon the
identification of place cells (neurons with receptive fields for current position in the environment) within the rat hippocampus
and the demonstration that hippocampal lesions impair place learning in therat. The inability to identify place cells within
the monkey hippocampus and the observation that unilateral hippocampal lesions do not selectively impair topographic behavior
in humans suggest that alternate regions may subserve this function in man. To examine the contribution of the hippocampus
and adjacent medial-temporal lobe structures to topographic learning in the human, a ‘virtual’ maze was used as a task environment
during functional magnetic resonance imaging studies. During the learning and recall of topographic information, medial-temporal
activity was confined to the para- hippocampal gyri. This activity accords well with the lesion site known to produce topographical
disorientation in humans. Activity was also observed in cortical areas known to project to the parahippocampus and previously
proposed to contribute to a network subserving spatially guided behavior.
To examine whether a simulated mobile telephone transmission at 915 MHz has an effect on cognitive function in man.
Thirty-six subjects in two groups were each given two training sessions and then three test sessions in a randomized three-way cross-over design. About 1 W mean power at 915 MHz from a quarter-wave antenna mounted on a physical copy of an analogue phone, as a sine wave, or modulated at 217 Hz with 12.5% duty cycle, or no power, was applied to the left squamous temple region of the subjects while they undertook a series of cognitive function tests lasting approximately 25-30 min. The second group was investigated for sleep, consumption of alcohol and beverages, and any other substances that might affect performance.
In both groups, the only test affected was the choice reaction time and this showed as an increase in speed (a decrease in reaction time). There were no changes in word, number or picture recall, or in spatial memory. While an effect of visit-order was evident suggesting a learning effect of repeat tests, the design of the study allowed for this. Additionally, there was no systematic error introduced as a result of consumption of substances or sleep time.
There was evidence of an increase in responsiveness, strongly in the analogue and less in the digital simulation, in choice reaction time. This could be associated with an effect on the angular gyrus that acts as an interface between the visual and speech centres and which lies directly under and on the same side as the antenna. Such an effect could be consistent with mild localized heating, or possibly a non-thermal response, which is nevertheless power-dependent.
Usage of mobile phones is rapidly increasing, but there is limited data on the possible effects of electromagnetic field (EMF) exposure on brain physiology. We investigated the effect of EMF vs. sham control exposure on waking regional cerebral blood flow (rCBF) and on waking and sleep electroencephalogram (EEG) in humans. In Experiment 1, positron emission tomography (PET) scans were taken after unilateral head exposure to 30-min pulse-modulated 900 MHz electromagnetic field (pm-EMF). In Experiment 2, night-time sleep was polysomnographically recorded after EMF exposure. Pulse-modulated EMF exposure increased relative rCBF in the dorsolateral prefrontal cortex ipsilateral to exposure. Also, pm-EMF exposure enhanced EEG power in the alpha frequency range prior to sleep onset and in the spindle frequency range during stage 2 sleep. Exposure to EMF without pulse modulation did not enhance power in the waking or sleep EEG. We previously observed EMF effects on the sleep EEG (A. A. Borbély, R. Huber, T. Graf, B. Fuchs, E. Gallmann and P. Achermann. Neurosci. Lett., 1999, 275: 207-210; R. Huber, T. Graf, K. A. Cote, L. Wittmann, E. Gallmann, D. Matter, J. Schuderer, N. Kuster, A. A. Borbély, and P. Achermann. Neuroreport, 2000, 11: 3321-3325), but the basis for these effects was unknown. The present results show for the first time that (1) pm-EMF alters waking rCBF and (2) pulse modulation of EMF is necessary to induce waking and sleep EEG changes. Pulse-modulated EMF exposure may provide a new, non-invasive method for modifying brain function for experimental, diagnostic and therapeutic purposes.
Mobile phones create a radio-frequency electromagnetic field (EMF) around them when in use, the effects of which on brain physiology in humans are not well known. We studied the effects of a commercial mobile phone on regional cerebral blood flow (rCBF) in healthy humans using positron emission tomography (PET) imaging. Positron emission tomography data was acquired using a double-blind, counterbalanced study design with 12 male subjects performing a computer-controlled verbal working memory task (letter 1-back). Explorative and objective voxel-based statistical analysis revealed that a mobile phone in operation induces a local decrease in rCBF beneath the antenna in the inferior temporal cortex and an increase more distantly in the prefrontal cortex. Our results provide the first evidence, suggesting that the EMF emitted by a commercial mobile phone affects rCBF in humans. These results are consistent with the postulation that EMF induces changes in neuronal activity.
The hippocampus (HC) and associated neural structures are hypothesized to contribute to individual differences in human spatial navigation. However, functional imaging studies and theoretical models underscore the importance of extrahippocampal regions as well. The purpose of the present study was to examine age differences in virtual environment navigation and to assess possible relationships between navigation and structural integrity of hippocampal and extrahippocampal brain regions. Healthy adult volunteers completed a virtual navigation task and underwent magnetic resonance imaging to assess volumes of the caudate nucleus (CN), cerebellum, HC, prefrontal, and primary visual cortices. Results demonstrated robust age-related differences in place learning. Moreover, individual differences in regional brain volumes as well as performance on the tests of memory and executive functions contributed to age differences in human place learning. High performance in a virtual navigation task was associated with larger volume of the CN and prefrontal gray and white matter. Larger hippocampal volume was associated with improved performance in the young but not old participants. We conclude that human navigation requires both hippocampal and extrahippocampal brain systems and draws on executive resources for successful performance.
We investigated the effects of radio frequency electromagnetic fields on brain physiology. Twenty-four healthy young men were exposed for 30 min to pulse-modulated or continuous-wave radio frequency electromagnetic fields (900 MHz; peak specific absorption rate 1 W/kg), or sham exposed. During exposure, participants performed cognitive tasks. Waking electroencephalogram was recorded during baseline, immediately after, and 30 and 60 min after exposure. Pulse-modulated radio frequency electromagnetic field exposure reduced reaction speed and increased accuracy in a working-memory task. It also increased spectral power in the waking electroencephalogram in the 10.5-11 Hz range 30 min after exposure. No effects were observed for continuous-wave radio frequency electromagnetic fields. These findings provide further evidence for a nonthermal biological effect of pulsed radio frequency electromagnetic fields.
This study assessed age differences in navigational behavior in a virtual Morris water maze (vMWM) and examined the ability of older adults to develop cognitive maps after vMWM experience. Compared with younger participants, older volunteers traversed a longer linear distance to locate the hidden platform. On the probe trial, younger volunteers spent a greater proportion of their total distance traveled in proximity to the platform and had more platform intersections. Analysis of map reproductions demonstrated that older participants used proximal objects to locate the goal but did not use room-geometry cues to aid navigation. These findings demonstrate age-related deficits on a laboratory measure of place learning and suggest that deficiencies in allocentric mapping may contribute to these deficits.
Two experiments were performed to assess the effects of intersections on distance cognition in the urban environment. A laboratory study examined estimated traversed distance as a function of the number of intersections along linear pathways. A field study investigated the distance estimates of individuals contacted in a shopping mall in Scottsdale, Arizona, to two points located in opposite directions along a major street adjacent to the mall. Data from the laboratory study revealed a strong positive relationship between the number of intersections along a traversed linear pathway and the estimated length of that path. Significant differences in estimated distance as a function of the number of intersections were also observed in the results of the field study. The findings are discussed in relation to information processing/storage and pathway segmentation models.
The results reported in literature on the RF effects on brain activity are not always consistent. We investi- gated whether these discrepancies result from the differences in the applied exposure systems (exposure duration, signal characteristics, induced fields as a function of subfunctional brain regions and time of day of the exposure). We also illustrated how many early studies insufficiently characterized the exposure by not providing the recom- mended minimal dosimetric quantities. Our objective was to derive the optimal exposure parameters for future stud- ies to further clarify the interactions of RF exposure on brain activity.
Rats were trained in six sessions to locate a submerged platform in a circular water maze. They were exposed to pulsed 2450-MHz microwaves (pulse width 2 μs, 500 128;pulses/s, average power density 2 mW/cm2, average whole body specific absorption rate 1.2 W/kg) for 1 h in a circular waveguide system immediately before each training session. One hour after the last training session, they were tested in a probe trial during which the platform was removed and the time spent in the quadrant of the maze in which the platform had been located during the 1-min trial was scored. Three groups of animals, microwave-exposed, sham-exposed, and cage control, were studied. Microwave-exposed rats were slower than sham-exposed and cage control rats in learning to locate the platform. However, there was no significant difference in swim speed among the three groups of animals, indicating that the difference in learning was not due to a change in motor functions or motivation. During the probe trial, microwave-exposed animals spent significantly less time in the quadrant that had contained the platform, and their swim patterns were different from those of the sham-exposed and cage control animals. The latter observation indicates that microwave-exposed rats used a different strategy in learning the location of the platform. These results show that acute exposure to pulsed microwaves caused a deficit in spatial “reference” memory in the rat. Bioelectromagnetics 21:52–56, 2000. © 2000 Wiley-Liss, Inc.
Rats were trained in six sessions to locate a submerged platform in a circular water maze. They were exposed to pulsed 2450-MHz microwaves (pulse width 2 micros, 500 128;pulses/s, average power density 2 mW/cm(2), average whole body specific absorption rate 1.2 W/kg) for 1 h in a circular waveguide system immediately before each training session. One hour after the last training session, they were tested in a probe trial during which the platform was removed and the time spent in the quadrant of the maze in which the platform had been located during the 1-min trial was scored. Three groups of animals, microwave-exposed, sham-exposed, and cage control, were studied. Microwave-exposed rats were slower than sham-exposed and cage control rats in learning to locate the platform. However, there was no significant difference in swim speed among the three groups of animals, indicating that the difference in learning was not due to a change in motor functions or motivation. During the probe trial, microwave-exposed animals spent significantly less time in the quadrant that had contained the platform, and their swim patterns were different from those of the sham-exposed and cage control animals. The latter observation indicates that microwave-exposed rats used a different strategy in learning the location of the platform. These results show that acute exposure to pulsed microwaves caused a deficit in spatial "reference" memory in the rat.
Rats were trained in six sessions to locate a submerged platform in a circular water-maze. They were exposed to a 1 mT, 60 Hz magnetic field for one hour in a Helmholtz coil system immediately before each training session. In addition, one hour after the last training session, they were tested in a probe trial during which the platform was removed and the time spent in the quadrant of the maze in which the platform was located during the training sessions was scored. Control animals were sham-exposed using the exposure system operating with the coils activated in an anti-parallel direction to cancel the fields. A group of "non-exposed" control animals was also included in the study. There was no significant difference between the magnetic field-exposed and control animals in learning to locate the platform. However, swim speed of the magnetic field-exposed rats was significantly slower than that of the controls. During the probe trial, magnetic field-exposed animals spent significantly less time in the quadrant that contained the platform, and their swim patterns were different from those of the controls. These results indicate that magnetic field exposure causes a deficit in spatial "reference" memory in the rat. Rats subjected to magnetic field exposure probably used a different behavioral strategy in learning the maze.
Topographical disorientation (TD) refers to impaired orientation and navigation in real-world environments. Although numerous cases have been reported, disagreement over neuroanatomical correlates remains. This has been contributed to by concern with the "essential defect," ambiguous terminology, and incomplete assessments. Attention to three factors permits a coherent understanding of the widely divergent descriptions of cognitive deficits and neuroanatomical findings: point in course (acute vs. chronic), characteristics of the environment, and a patient's specific cognitive deficits. Defects in visual learning/recognition of topographical scenes or spatial-topographical knowledge are common, but the "agnosia" versus "amnesia" dichotomy is an oversimplification: Careful assessment typically reveals impairment in both realms. Anterograde TD is most highly associated with medial occipitotemporal lesions in either hemisphere, especially posterior parahippocampal gyrus, whereas TD consequent to right parietal damage tends to be time-limited. Persistent retrograde TD is attributable to right medial occipitotemporal lesions.
To investigate whether the electromagnetic field (EMF) emitted by digital radiotelephone handsets affects the brain, healthy, young subjects were exposed during an entire night-time sleep episode to an intermittent radiation schedule (900 MHz; maximum specific absorption rate 1 W/kg) consisting of alternating 15-min on-15-min off intervals. Compared with a control night with sham exposure, the amount of waking after sleep onset was reduced from 18 to 12 min. Spectral power of the electroencephalogram in non-rapid eye movement sleep was increased. The maximum rise occurred in the 10-11 Hz and 13.5-14 Hz bands during the initial part of sleep and then subsided. The results demonstrate that pulsed high-frequency EMF in the range of radiotelephones may promote sleep and modify the sleep EEG.
Mobile phones (MP) are used extensively and yet little is known about the effects they may have on human physiology. There have been conflicting reports regarding the relation between MP use and the electroencephalogram (EEG). The present study suggests that this conflict may be due to methodological differences such as exposure durations, and tests whether exposure to an active MP affects EEG as a function of time.
Twenty-four subjects participated in a single-blind fully counterbalanced cross-over design, where both resting EEG and phase-locked neural responses to auditory stimuli were measured while a MP was either operating or turned off.
MP exposure altered resting EEG, decreasing 1-4 Hz activity (right hemisphere sites), and increasing 8-12 Hz activity as a function of exposure duration (midline posterior sites). MP exposure also altered early phase-locked neural responses, attenuating the normal response decrement over time in the 4-8 Hz band, decreasing the response in the 1230 Hz band globally and as a function of time, and increasing midline frontal and lateral posterior responses in the 30-45 Hz band.
Active MPs affect neural function in humans and do so as a function of exposure duration. The temporal nature of this effect may contribute to the lack of consistent results reported in the literature.
This study assessed age differences in navigational behavior in a virtual Morris water maze (vMWM) and examined the ability of older adults to develop cognitive maps after vMWM experience. Compared with younger participants, older volunteers traversed a longer linear distance to locate the hidden platform. On the probe trial, younger volunteers spent a greater proportion of their total distance traveled in proximity to the platform and had more platform intersections. Analysis of map reproductions demonstrated that older participants used proximal objects to locate the goal but did not use room-geometry cues to aid navigation. These findings demonstrate age-related deficits on a laboratory measure of place learning and suggest that deficiencies in allocentric mapping may contribute to these deficits.
The effects of electromagnetic fields (EMF) emitted by cellular phones on the event related desynchronization/synchronization (ERD/ERS) of the 4-6, 6-8, 8-10, and 10-12 Hz electroencephalogram (EEG) frequency bands were studied in 24 normal subjects performing an auditory memory task. This study was a systematic replication of our previous work. In the present double blind study, all subjects performed the memory task both with and without exposure to a digital 902 MHz field in a counterbalanced order. We were not able to replicate the findings from our earlier study. All eight of the significant changes in our earlier study were not significant in the present double blind replication. Also, the effect of EMF on the number of incorrect answers in the memory task was inconsistent. We previously reported no significant effect of EMF exposure on the number of incorrect answers in the memory task, but a significant increase in errors was observed in the present study. We conclude that EMF effects on the EEG and on the performance on memory tasks may be variable and not easily replicable for unknown reasons.
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.
Conflicting results have recently emerged from human provocation studies that addressed the possible health hazards of radio frequency (RF) field exposure from mobile phones. Different findings may have resulted from exposures that are poorly defined and difficult to compare. The aim of this study was to develop guidelines to facilitate the development of exposure systems for human volunteer studies which lead to reproducible results and which provide maximum relevance with respect to the assessment of the safety of mobile technology. The most important exposure parameters are discussed such as the signal, field distribution, and field strength, as well as the minimum requirements for the setup and dosimetry.
The increasing use of mobiles phones (MP) has raised the problem of the effects of daily electromagnetic fields (EMF) exposure on human health. To date several studies have been published concerning the effects of acute MP exposure on psychomotor performances. This study investigated the effects of daily exposure to GSM 900 type MP on cognitive function. Fifty-five subjects (27 male and 28 female) were divided into two groups: a group with MP switched on and a group with MP switched off. The two groups were matched according to age, gender, and IQ. This double blind study lasted for 45 days and was divided in three periods: baseline (BLP, 2 days), exposure (EP, 27 days), and recovery (RP, 13 days). Subjects were exposed during EP and sham exposed during RP for 2 h/day, 5 days/week. The neuropsychological test battery composed of 22 tasks screened four neuropsychological categories: information processing, attention capacity, memory function, and executive function. This neuropsychological battery was performed four times on day 2 (BLP), day 15 (EP), day 29 (EP), and day 43 (RP). Our results indicate that daily MP use has no effect on cognitive function after a 13-h rest period.
We examine whether a standard mobile exposure at 902 MHz has a significant effect on cognitive function in 18 children 10-12 years of age. These were in a single group in which each child was given a single training session and then three test sessions in a randomized, three-way crossover design, using the cognitive drug research (CDR) cognitive assessment system. Exposures were 0, 0.025, or 0.25 W from a standard Nokia 3110 mobile phone handset mounted on a plastic headset in normal use position. The results of testing showed that the baseline (0 W) performance for the reaction time measurements was considerably slower than for the comparable measures in adult. There was a tendency for reaction time to be shorter during exposure to radiation than in the sham (baseline) condition, an effect that was most marked for simple reaction time. However, no effects reached statistical significance after Bonferroni correction. Therefore, we conclude that this study on 18 children did not replicate our earlier finding in adults that exposure to microwave radiation was associated with a reduction in reaction time. It should be noted that the present study investigated the effects of radiation from a GSM handset, whereas in our previous study the effect on reaction time was observed only with a more powerful analogue handset.
In this preliminary study we investigate gender differences in object location memory. Our purpose is to extend the results about object location memory obtained in laboratory settings to a real 3-D environment and to further distinguish the specific components involved in this kind of memory by considering the strategies adopted to perform the task. To do this, we join the three-level model of spatial representations (landmark, route, and survey) proposed by Siegel and White (1975) with the three subcomponents of spatial memory (what, where, and what + where) identified by Postma and De Haan (1996). We adopted the object relocation task devised by Postma and De Haan (1996), adapted to a real environment. Seven common objects were placed on the floor of a cylindrical room. Sixty-four males and 64 females were asked to memorize the spatial layout. Next, the experimenter moved the objects to a different position along with seven new objects and the participants had to relocate the original objects to their initial positions. In line with Postma, Izendoorn, and De Haan (1998), we found no gender difference in object recognition, and in recalling absolute distance and categorical spatial relations; however males were better than females in recalling the distance between objects and the size of the layout. Overall, the data show a male advantage in some components of spatial cognition closely linked to the encoding of the metric structure of the spatial relationships at both route and survey level.
Age-related declines in spatial navigation are well-known in human and non-human species. Studies in non-human species suggest that alteration in hippocampal and other neural circuitry may underlie behavioral deficits associated with aging but little is known about the neural mechanisms of human age-related decline in spatial navigation. The purpose of the present study was to examine age differences in functional brain activation during virtual environment navigation. Voxel-based analysis of activation patterns in young subjects identified activation in the hippocampus and parahippocampal gyrus, retrosplenial cortex, right and left lateral parietal cortex, medial parietal lobe and cerebellum. In comparison to younger subjects, elderly participants showed reduced activation in the hippocampus and parahippocampal gyrus, medial parietal lobe and retrosplenial cortex. Relative to younger participants elderly subjects showed increased activation in anterior cingulate gyrus and medial frontal lobe. These results provide evidence of age specific neural networks supporting spatial navigation and identify a putative neural substrate for age-related differences in spatial memory and navigational skill.
The rapidly evolving mobile phone technology raised public concern about the possibility of associated adverse health effects. The current body of evidence is summarized addressing epidemiological studies, studies investigating adverse biological effects, other biological effects, basic mechanisms and indirect effects. Currently, the balance of evidence from epidemiological studies suggests that there is no association between mobile phone radiation and cancer. This finding is consistent with experimental results. There is some evidence for biological effects, which, however, are not necessarily hazardous for humans. No basic mechanisms of biological effects have been consistently identified yet. Using a mobile phone while driving a car is significantly associated with a higher risk of vehicle collisions, independently of the use of hands-free kits. Medical equipment or implanted pacemakers may be affected by mobile phone radiation under very specific conditions. Current studies, however are affected by several limitations and do not generally exclude any increased health risk. Further high-quality research is therefore necessary. Furthermore, it is important that the results of scientific research are communicated to the public in a transparent and differentiated way.
Previous research has suggested that exposure to radiofrequency electromagnetic fields increases electroencephalogram spectral power in non-rapid eye movement sleep. Other sleep parameters have also been affected following exposure. We examined whether aspects of sleep architecture show sensitivity to electromagnetic fields emitted by digital mobile phone handsets. Fifty participants were exposed to electromagnetic fields for 30 min prior to sleep. Results showed a decrease in rapid eye movement sleep latency and increased electroencephalogram spectral power in the 11.5-12.25 Hz frequency range during the initial part of sleep following exposure. These results are evidence that mobile phone exposure prior to sleep may promote rapid eye movement sleep and modify the sleep electroencephalogram in the first non-rapid eye movement sleep period.
Recent studies have indicated that acute exposure to low level radiofrequency (RF) electromagnetic fields generated by mobile phones affects human cognition. However, the relatively small samples used, in addition to methodological problems, make the outcomes of these studies difficult to interpret. In our study we tested a large sample of volunteers (168) using a series of cognitive tasks apparently sensitive to RF exposure (a simple reaction task, a vigilance task, and a subtraction task). Participants performed those tasks twice, in two different sessions. In one session they were exposed to RFs, with half of subjects exposed to GSM signals and the other half exposed to CW signals, while in the other session they were exposed to sham signals. No significant effects of RF exposure on performance for either GSM or CW were found, independent of whether the phone was positioned on the left or on the right side.
The aim of the present study was to investigate the effect of exposure to a mobile phone-like radiofrequency (RF) electromagnetic field on persons experiencing subjective symptoms when using mobile phones (MP). Twenty subjects with MP-related symptoms were recruited and matched with 20 controls without MP-related symptoms. Each subject participated in two experimental sessions, one with true exposure and one with sham exposure, in random order. In the true exposure condition, the test subjects were exposed for 30 min to an RF field generating a maximum SAR(1g) in the head of 1 W/kg through an indoor base station antenna attached to a 900 MHz GSM MP. The following physiological and cognitive parameters were measured during the experiment: heart rate and heart rate variability (HRV), respiration, local blood flow, electrodermal activity, critical flicker fusion threshold (CFFT), short-term memory, and reaction time. No significant differences related to RF exposure conditions were detected. Also no differences in baseline data were found between subject groups, except for the reaction time, which was significantly longer among the cases than among the controls the first time the test was performed. This difference disappeared when the test was repeated. However, the cases differed significantly from the controls with respect to HRV as measured in the frequency domain. The cases displayed a shift in low/high frequency ratio towards a sympathetic dominance in the autonomous nervous system during the CFFT and memory tests, regardless of exposure condition. This might be interpreted as a sign of differences in the autonomous nervous system regulation between persons with MP related subjective symptoms and persons with no such symptoms.
The possible effects of continuous wave (CW) and pulse modulated (PM) electromagnetic field (EMF) on human cognition was studied in 36 healthy male subjects. They performed cognitive tasks while exposed to CW, PM, and sham EMF. The subjects performed the same tasks twice during each session; once with left-sided and once with right-sided exposure. The EMF conditions were spread across three testing sessions, each session separated by 1 week. The exposed hemisphere, EMF condition, and test order were counterbalanced over all subjects. We employed a double-blind design: both the subject and the experimenter were unaware of the EMF condition. The EMF was created with a signal generator connected via amplifier to a dummy phone antenna, creating a power output distribution similar to the original commercial mobile phone. The EMF had either a continuous power output of 0.25 W (CW) or pulsed power output with a mean of 0.25 W. An additional control group of 16 healthy male volunteers performed the same tasks without any exposure equipment to see if mere presence of the equipment could have affected the subjects' performance. No effects were found between the different EMF conditions, separate hemisphere exposures, or between the control and experimental group. In conclusion, the current results indicate that normal mobile phones have no discernible effect on human cognitive function as measured by behavioral tests.
The aim of this study was to provide the information necessary to enable the comparison of exposure conditions in different human volunteer studies published by the research groups at the Universities of Turku, Swinburne, and Zurich. The latter applied a setup optimized for human volunteer studies in the context of risk assessment while the first two applied a modified commercial mobile phone for which detailed dosimetric data were lacking. While the Zurich Setup exposed the entire cortex of the target hemisphere, the other two setups resulted in only very localized exposure of the upper cheek, and concentrated on a limited area of the middle temporal gyrus just above the ear. The resulting peak spatial SAR averaged over 1 g of the cortex was 0.19 W/kg of the Swinburne Setup, and 0.31 W/kg for the Turku Setup, compared to 1 W/kg for the Zurich Setup. The average exposure of the thalamus was 5% and 9% of the Zurich Setup results for the Swinburne and Turku Setups, respectively. In general, the phone-based setup results in only reasonably defined exposures in a very limited area around the maximum exposure; the exposure of the rest of the cortex was low, and may vary greatly as a function of the setup, position, and local anatomy. The analysis confirms the need for a carefully designed exposure setup that exposes the relevant brain areas to a well-defined level in human volunteer studies, and shows that studies can only be properly compared and replicated if sufficiently detailed dosimetric information is available.
Object-location memory is the only spatial task where female subjects have been shown to outperform males. This result is not consistent across all studies, and may be due to the combination of the multi-component structure of object location memory with the conditions under which different studies were done. Possible gender differences in object location memory and its component object identity memory were assessed in the present study. In order to disentangle these two components, an object location memory task (in which objects had to be relocated in daily environments), and a separate object identity recognition task were carried out. This study also focused on the conditions under which object locations were encoded and retrieved. Only half of the participants were aware of the fact that object locations had to be retrieved later on. Moreover, by applying the 'process dissociation procedure' to the object location memory assessments and the 'remember-know' paradigm to the object identity measure, the amount of explicit (conscious) and implicit (unconscious) retrieval was estimated for each component. In general, females performed better than males on the object location memory task. However, when controlled for object identity memory, females no longer outperformed males, whereas they did not obtain a higher general object identity memory score, nor did they have more explicit or implicit recollection of the object identities. These complicated effects might stem from a difference between males and females, in the way locations or associations between objects and locations are retrieved. In general, participants had more explicit (conscious) recollection than implicit (unconscious) recollection. No effect of encoding context was found, nor any interaction effect of gender, encoding and retrieval context.
Findings from prior studies of possible health and physiological effects from mobile phone use have been inconsistent. Exposure periods in provocation studies have been rather short and personal characteristics of the participants poorly defined. We studied the effect of radiofrequency field (RF) on self-reported symptoms and detection of fields after a prolonged exposure time and with a well defined study group including subjects reporting symptoms attributed to mobile phone use. The design was a double blind, cross-over provocation study testing a 3-h long GSM handset exposure versus sham. The study group was 71 subjects age 18-45, including 38 subjects reporting headache or vertigo in relation to mobile phone use (symptom group) and 33 non-symptomatic subjects. Symptoms were scored on a 7-point Likert scale before, after 1(1/2) and 2(3/4) h of exposure. Subjects reported their belief of actual exposure status. The results showed that headache was more commonly reported after RF exposure than sham, mainly due to an increase in the non-symptom group. Neither group could detect RF exposure better than by chance. A belief that the RF exposure had been active was associated with skin symptoms. The higher prevalence of headache in the non-symptom group towards the end of RF exposure justifies further investigation of possible physiological correlates. The current study indicates a need to better characterize study participants in mobile phone exposure studies and differences between symptom and non-symptom groups.
Does the experimental outcome of human provocation studies depend on the design specifics of the exposure setup? FTG-Work-shop Acute exposure to a 60 Hz magnetic field affects rats' water-maze performance
- N Kuster
- M Murbach
- S Kü
- Achermann
Kuster N, Murbach M, Kü S, Achermann P. 2007. Does the experimental outcome of human provocation studies depend on the design specifics of the exposure setup? FTG-Work-shop, November 5th–7th, Stuttgart, Germany. Lai H, Carino MA, Ushijima I. 1998. Acute exposure to a 60 Hz magnetic field affects rats' water-maze performance. Bio-electromagnetics 19:117–122.
Är du rädd för din mobiltelefon? (Are you afraid of your mobile phone In Swedish?) Stockholm: TCO (The Swedish confederation for Professional Employees)
- L Orpana
Orpana L. 2004. Ä r du rädd för din mobiltelefon? (Are you afraid of
your mobile phone In Swedish?) Stockholm: TCO (The
Swedish confederation for Professional Employees). (TCO
Granskar nr 4/2004).
Mobile phone affects cerebral blood flow in humans The parahippocampus subserves topographical learning in man
- S Aalto
- C Haarala
- A Brü
- H Sipil
- H Hämälä
- Jo Aguirre Gk
- Ja Detre
- D Alsop Dc
- M Esposito
Aalto S, Haarala C, Brü A, Sipil H, Hämälä H, Rinne JO. 2006. Mobile phone affects cerebral blood flow in humans. J Cereb Blood Flow Metab 26:885–890. doi:10.1038/ sj.jcbfm.9600279; published online 22 February 2006. Aguirre GK, Detre JA, Alsop DC, D'Esposito M. 1996. The parahippocampus subserves topographical learning in man. Cereb Cortex 6:823–829.
Acute exposure to a 60 Hz magnetic field affects rats' water-maze performance
- Lai