The effect of exposure to radiofrequency electromagnetic fields on cognitive performance in human experimental studies: Systematic review and meta-analyses.

BACKGROUND: The objective of this review is to evaluate the associations between short-term exposure to radiofrequency electromagnetic fields (RF-EMF) and cognitive performance in human experimental studies. METHODS: Online databases (PubMed, Embase, Scopus, Web of Science and EMF-Portal) were searched for studies that evaluated effects of exposure to RF-EMF on seven domains of cognitive performance in human experimental studies. The assessment of study quality was based on the Risk of Bias (RoB) tool developed by the Office of Health Assessment and Translation (OHAT). Random effects meta-analyses of Hedges's g were conducted separately for accuracy- and speed-related performance measures of various cognitive domains, for which data from at least two studies were available. Finally, the certainty of evidence for each identified outcome was assessed according to Grading of Recommendations Assessment, Development, and Evaluation (GRADE). RESULTS: 57,543 records were identified and 76 studies (80 reports) met the inclusion criteria. The included 76 studies with 3846 participants, consisting of humans of different age, sex and health status from 19 countries, were conducted between 1989 and 2021. Quantitative data from 50 studies (52 reports) with 2433 participants were included into the meta-analyses. These studies were performed in 15 countries between 2001 and 2021. The majority of the included studies used head exposure with GSM 900 uplink. None of the meta-analyses observed a statistically significant effect of RF-EMF exposure compared to sham on cognitive performance as measured by the confidence interval surrounding the Hedges's g or the significance of the z-statistic. For the domain Orientation and Attention, subclass Attention - Attentional Capacity RF-EMF exposure results in little to no difference in accuracy (Hedges's g 0.024, 95 % CI [-0.10; 0.15], I2 = 28 %, 473 participants). For the domain Orientation and Attention, subclass Attention - Concentration / Focused Attention RF-EMF exposure results in little to no difference in speed (Hedges's g 0.005, 95 % CI [-0.17; 0.18], I2 = 7 %, 132 participants) and probably results in little to no difference in accuracy; it does not reduce accuracy (Hedges's g 0.097, 95 % CI [-0.05; 0.24], I2 = 0 %, 217 participants). For the domain Orientation and Attention, subclass Attention - Vigilance RF-EMF exposure probably results in little to no difference in speed and does not reduce speed (Hedges's g 0.118, 95 % CI [-0.04; 0.28], I2 = 41 %, 247 participants) and results in little to no difference in accuracy (Hedges's g 0.042, 95 % CI, [-0.09; 0.18], I2 = 0 %, 199 participants). For the domain Orientation and Attention, subclass Attention - Selective Attention RF-EMF exposure probably results in little to no difference in speed and does not reduce speed (Hedges's g 0.080, 95 % CI [-0.09; 0.25], I2 = 63 %, 452 participants); it may result in little to no difference in accuracy, but it probably does not reduce accuracy (Hedges's g 0.178, 95 % CI [-0.02; 0.38], I2 = 68 %, 480 participants). For the domain Orientation and Attention, subclass Attention - Divided Attention RF-EMF exposure results in little to no difference in speed (Hedges's g -0.010, 95 % CI [-0.14; 0.12], I2 = 5 %, 307 participants) and may result in little to no difference in accuracy (Hedges's g -0.089, 95 % CI [-0.35; 0.18], I2 = 53 %, 167 participants). For the domain Orientation and Attention, subclass Processing Speed - Simple Reaction Time Task RF-EMF exposure results in little to no difference in speed (Hedges's g 0.069, 95 % CI [-0.02; +0.16], I2 = 29 %, 820 participants). For the domain Orientation and Attention, subclass Processing Speed - 2-Choice Reaction Time Task RF-EMF exposure results in little to no difference in speed (Hedges's g -0.023, 95 % CI [-0.13; 0.08], I2 = 0 %, 401 participants), and may result in little to no difference in accuracy (Hedges's g -0.063, 95 % CI [-0.38; 0.25], I2 = 63 %, 117 participants). For the domain Orientation and Attention, subclass Processing Speed - >2-Choice Reaction Time Task RF-EMF exposure results in little to no difference in speed (Hedges's g -0.054, 95 % CI [-0.14; 0.03], I2 = 0 %, 544 participants) and probably results in little to no difference in accuracy (Hedges's g -0.129, 95 % CI [-0.30; 0.04], I2 = 0 %, 131 participants). For the domain Orientation and Attention, subclass Processing Speed - Other Tasks RF-EMF exposure probably results in little to no difference in speed and does not reduce speed (Hedges's g 0.067, 95 % CI [-0.12; 0.26], I2 = 38 %, 249 participants); it results in little to no difference in accuracy (Hedges's g 0.036, 95 % CI [-0.08; 0.15], I2 = 0 %, 354 participants). For the domain Orientation and Attention, subclass Working Memory - n-back Task (0-3-back) we found Hedges's g ranging from -0.090, 95 % CI [-0.18; 0.01] to 0.060, 95 % CI [-0.06; 0.18], all I2 = 0 %, 237 to 474 participants, and conclude that RF-EMF exposure results in little to no difference in both speed and accuracy. For the domain Orientation and Attention, subclass Working Memory - Mental Tracking RF-EMF exposure results in little to no difference in accuracy (Hedges's g -0.047, 95 % [CI -0.15; 0.05], I2 = 0 %, 438 participants). For the domain Perception, subclass Visual and Auditory Perception RF-EMF exposure may result in little to no difference in speed (Hedges's g -0.015, 95 % CI [-0.23; 0.195], I2 = 0 %, 84 participants) and probably results in little to no difference in accuracy (Hedges's g 0.035, 95 % CI [-0.13; 0.199], I2 = 0 %, 137 participants). For the domain Memory, subclass Verbal and Visual Memory RF-EMF exposure probably results in little to no difference in speed and does not reduce speed (Hedges's g 0.042, 95 % CI [-0.15; 0.23], I2 = 0 %, 102 participants); it may result in little to no difference in accuracy (Hedges's g -0.087, 95 % CI [-0.38; 0.20], I2 = 85 %, 625 participants). For the domain Verbal Functions and Language Skills, subclass Verbal Expression, a meta-analysis was not possible because one of the two included studies did not provide numerical values. Results of both studies did not indicate statistically significant effects of RF-EMF exposure on both speed and accuracy. For the domain Construction and Motor Performance, subclass Motor Skills RF-EMF exposure may reduce speed, but the evidence is very uncertain (Hedges's g -0.919, 95 % CI [-3.09; 1.26], I2 = 96 %, 42 participants); it probably results in little to no difference in accuracy and does not reduce accuracy (Hedges's g 0.228, 95 % CI [-0.01; 0.46], I2 = 0 %, 109 participants). For the domain Concept Formation and Reasoning, subclass Reasoning RF-EMF exposure results in little to no difference in speed (Hedges's g 0.010, 95 % CI [-0.11; 0.13], I2 = 0 %, 263 participants) and probably results in little to no difference in accuracy and does not reduce accuracy (Hedges's g 0.051, 95 % CI [-0.14; 0.25], I2 = 0 %, 100 participants). For the domain Concept Formation and Reasoning, subclass Mathematical Procedures RF-EMF exposure results in little to no difference in speed (Hedges's g 0.033, 95 % CI [-0.12; 0.18], I2 = 0 %, 168 participants) and may result in little to no difference in accuracy but probably does not reduce accuracy (Hedges's g 0.232, 95 % CI [-0.12; +0.59], I2 = 86 %, 253 participants). For the domain Executive Functions there were no studies. DISCUSSION: Overall, the results from all domains and subclasses across their speed- and accuracy-related outcome measures according to GRADE provide high to low certainty of evidence that short-term RF-EMF exposure does not reduce cognitive performance in human experimental studies. For 16 out of 35 subdomains some uncertainty remains, because of limitations in the study quality, inconsistency in the results or imprecision of the combined effect size estimate. Future research should focus on construction and motor performance, elderly, and consideration of both sexes. OTHER: This review was partially funded by the WHO radioprotection programme. The protocol for this review was registered in Prospero reg. no. CRD42021236168 and published in Environment International (Pophof et al. 2021).

Numerical assessment of induced electric fields in a worker's hand with commonly used metallic implants under exposure to low frequency magnetic fields.

The European Union's Workers' Directive 2013/35/EU on the minimum health and safety requirements regarding the exposure of workers to electromagnetic fields specifies action levels (ALs) for external electric and magnetic fields, which should protect against induced tissue-internal electric field strengthEiabove the exposure limit values, the latter being defined in order to prevent tissue stimulation at low frequencies. However, although 2013/35/EU explicitly calls for the protection of 'workers at particular risk' (including workers with metallic implants), the AL specified in the Directive have been derived under the assumption that there are no metallic parts present inside the body. Therefore, in the present work, we analysed the situation of a worker's hand and forearm bearing metallic implants (Herbert screw and volar radius plate) used for osteosynthesis after the most common bone fractures of the hand/forearm, exposed to low frequency magnetic fields. The uniform exposure of the whole hand and forearm as well as the exposure to a specific and widely used device, a deactivator for single-use labels of acousto-magnetic electronic article surveillance systems, were considered based on numerical computations using a high-resolution anatomical hand and forearm model. The results obtained indicated that the maximum induced electric field strength averaged in a volume of 2 mm × 2 mm × 2 mm cube was higher in the presence of the metallic implants by a factor of up to 4.2 for bone tissue and 2.3 for soft tissue compared with the case without an implant. Hence, it is obvious that the local induced electric field strengths may be substantially increased by the implants. The extent of this increase, however, is highly dependent on the implant's position inside the body, the implant's geometry, and the field distribution and orientation with respect to the anatomical structure and the implant.

The effect of romosozumab on bone mineral density depending on prior treatment: a prospective, multicentre cohort study in Switzerland.

This multicentre, prospective cohort study measured the effect of romosozumab for 12 months on bone mineral density, taking into account prior therapies. Prior antiresorptive therapy blunted the BMD response to romosozumab, and the duration was correlated with BMD changes at both the lumbar spine and total hip. INTRODUCTION: In Switzerland, romosozumab is administered to high-risk osteoporosis patients. Our study aimed to assess the effect of romosozumab on bone mineral density (BMD), taking into account prior therapies. METHODS: This multicentre, prospective cohort study measured the effect of romosozumab for 12 months in patients in a nationwide Swiss osteoporosis registry. BMD and bone turnover marker (P1NP and CTX) changes were measured and compared between pre-treated and treatment naïve patients. RESULTS: Ninety-nine patients (92 women and 7 men, median age 71 years [65, 76]) were enrolled from January 2021 to December 2023. Among them, 22 had no prior treatment before romosozumab, while 77 had previous therapy (including 23 with a history of prior teriparatide therapy), with a median duration of 6 years [4, 11] of cumulative antiresorptive treatment. Over 12 months, romosozumab led to BMD changes of 10.3% [7.5, 15.5] at the lumbar spine, 3.1% [1.1, 5.8] at the total hip and 3.1% [0.5, 5.3] at the femoral neck, indicating notable variability. Significantly lower BMD responses were observed in pre-treated patients, with the duration of prior antiresorptive therapy inversely associated with BMD increases at the lumbar spine and hip. Other predictors of BMD changes at the total hip included baseline T-scores at the hip, body mass index and baseline CTX level, while the BMD response at the lumbar spine was associated with the lumbar spine T-score at baseline, age and baseline CTX level. CONCLUSION: Prior antiresorptive therapy blunted the BMD response to romosozumab, and the duration was correlated with BMD changes at both the lumbar spine and total hip.

Mobile phone specific radiation disturbs cytokinesis and causes cell death but not acute chromosomal damage in buccal cells: Results of a controlled human intervention study.

Several human studies indicate that mobile phone specific electromagnetic fields may cause cancer in humans but the underlying molecular mechanisms are currently not known. Studies concerning chromosomal damage (which is causally related to cancer induction) are controversial and those addressing this issue in mobile phone users are based on the use of questionnaires to assess the exposure. We realized the first human intervention trial in which chromosomal damage and acute toxic effects were studied under controlled conditions. The participants were exposed via headsets at one randomly assigned side of the head to low and high doses of a UMTS signal (n = 20, to 0.1 W/kg and n = 21 to 1.6 W/kg Specific Absorption Rate) for 2 h on 5 consecutive days. Before and three weeks after the exposure, buccal cells were collected from both cheeks and micronuclei (MN, which are formed as a consequence of structural and numerical chromosomal aberrations) and other nuclear anomalies reflecting mitotic disturbance and acute cytotoxic effects were scored. We found no evidence for induction of MN and of nuclear buds which are caused by gene amplifications, but a significant increase of binucleated cells which are formed as a consequence of disturbed cell divisions, and of karyolitic cells, which are indicative for cell death. No such effects were seen in cells from the less exposed side. Our findings indicate that mobile phone specific high frequency electromagnetic fields do not cause acute chromosomal damage in oral mucosa cells under the present experimental conditions. However, we found clear evidence for disturbance of the cell cycle and cytotoxicity. These effects may play a causal role in the induction of adverse long term health effects in humans.

Nonsinusoidalin situelectric field caused by magnetic deactivator device for EAS labels-assessment of field strength inside a detailed anatomical hand model.

In order to evaluate the localised magnetic field (MF) exposure of the cashier's hand due to a particular demagnetization device (deactivator) for single-use labels of an acoustomagnetic (AM) electronic article surveillance (EAS) system, comprehensive measurements of the MF near the surface of the deactivator, and numerical computations of the induced electric field strengthEi, were performed in high-resolution anatomical hand models of different postures and positions with respect to the deactivator. The measurement results for magnetic inductionBwere assessed with respect to the action levels (AL) for limb exposure, and the computational results forEiwere evaluated with respect to the exposure limit values (ELV) for health effects according to European Union (EU) directive 2013/35/EU. For the ELV-based assessment, a maximum of the 2 × 2 × 2 mm3averagedEi(maxEi,avg) and the respective 99.9th, 99.5th, and 99.0th percentiles were used. As the MF impulse emitted by the deactivator for demagnetization of the AM-EAS labels was highly nonsinusoidal, measurement results were assessed based on the weighted peak method in the time domain (WPM-TD). A newly developed scaling technique was proposed to also apply the WPM-TD to the assessment of the (nonsinusoidal)Eiregarding the ELV. It was used to calculate the resulting WPM-TD-based exposure index (EI) from frequency domain computations. The assessment regarding the AL for limbs yielded peak values of magnetic induction of up to 97 mT (measured with a 3 cm2MF probe on top of the deactivator surface) corresponding to an EI of 443%. However, this was considered an overestimation of the actual exposure in terms ofEias the AL were intentionally defined conservatively. A WPM-TD-based assessment ofEifinally led to the worst case EI of up to 135%, 93%, 78%, and 72% when using the maxEi,avg, 99.9th, 99.5th, and 99.0th percentiles, respectively.

Measurement and image-based estimation of dielectric properties of biological tissues -past, present, and future.

The dielectric properties of biological tissues are fundamental pararmeters that are essential for electromagnetic modeling of the human body. The primary database of dielectric properties compiled in 1996 on the basis of dielectric measurements at frequencies from 10 Hz to 20 GHz has attracted considerable attention in the research field of human protection from non-ionizing radiation. This review summarizes findings on the dielectric properties of biological tissues at frequencies up to 1 THz since the database was developed. Although the 1996 database covered general (normal) tissues, this review also covers malignant tissues that are of interest in the research field of medical applications. An intercomparison of dielectric properties based on reported data is presented for several tissue types. Dielectric properties derived from image-based estimation techniques developed as a result of recent advances in dielectric measurement are also included. Finally, research essential for future advances in human body modeling is discussed.

Design and Dosimetric Characterization of a Broadband Exposure Facility for In Vitro Experiments in the Frequency Range 18-40.5 GHz.

A novel exposure facility for exposing cell monolayers to centimeter and millimeter waves (18-40.5 GHz) used by future 5G mobile communication technology and similar applications has been developed. A detailed dosimetric characterization of the apparatus for frequencies of 27 and 40.5 GHz and 60 mm petri dishes, used in a presently ongoing study on human dermal fibroblasts and keratinocytes, was carried out. The exposure facility enables a well-defined, randomized, and blinded application of sham exposure and exposure with selectable values of incident power flux density, and additionally provides the possibility of continuous monitoring of the sample temperature during exposure while it does not require significant deviations from routine in vitro handling procedures, i.e. petri dishes are not required to be placed inside waveguides or TEM cells. Mean specific absorption rate (SAR) values inside the cell monolayer of 115 W/kg (27 GHz) and 160 W/kg (40.5 GHz) per watt antenna input power and corresponding transmitted power density (St ) values at the bottom of the cell monolayer of 65 W/m2 (27 GHz) and 70 W/m2 (40.5 GHz) per watt antenna input power can be achieved, respectively. For reasonable amounts of harvested cells (80% of petri dish bottom area), the variation (max/min) of SAR and St over the cell monolayer remains below 3.7 dB (27 GHz) and 3.0 dB (40.5 GHz), respectively. © 2021 Bioelectromagnetics Society.

The effect of radiofrequency electromagnetic fields (RF-EMF) on biomarkers of oxidative stress in vivo and in vitro: A protocol for a systematic review.

BACKGROUND: Oxidative stress is conjectured to be related to many diseases. Furthermore, it is hypothesized that radiofrequency fields may induce oxidative stress in various cell types and thereby compromise human and animal health. This systematic review (SR) aims to summarize and evaluate the literature related to this hypothesis. OBJECTIVES: The main objective of this SR is to evaluate the associations between the exposure to radiofrequency electromagnetic fields and oxidative stress in experimental models (in vivo and in vitro). METHODS: The SR framework has been developed following the guidelines established in the WHO Handbook for Guideline Development and the Handbook for Conducting a Literature-Based Health Assessment). We will include controlled in vivo and in vitro laboratory studies that assess the effects of an exposure to RF-EMF on valid markers for oxidative stress compared to no or sham exposure. The protocol is registered in PROSPERO. We will search the following databases: PubMed, Embase, Web of Science Core Collection, Scopus, and the EMF-Portal. The reference lists of included studies and retrieved review articles will also be manually searched. STUDY APPRAISAL AND SYNTHESIS METHOD: Data will be extracted according to a pre-defined set of forms developed in the DistillerSR online software and synthesized in a meta-analysis when studies are judged sufficiently similar to be combined. If a meta-analysis is not possible, we will describe the effects of the exposure in a narrative way. RISK OF BIAS: The risk of bias will be assessed with the NTP/OHAT risk of bias rating tool for human and animal studies. We will use GRADE to assess the certainty of the conclusions (high, moderate, low, or inadequate) regarding the association between radiofrequency electromagnetic fields and oxidative stress. FUNDING: This work was funded by the World Health Organization (WHO). REGISTRATION: The protocol was registered on the PROSPERO webpage on July 8, 2021.

Current practice of transitional care for adolescents and young adults in Swiss paediatric and adult rheumatology centres.

BACKGROUND: About half of all children with rheumatic diseases need continuous medical care during adolescence and adulthood. A good transition into adult rheumatology is essential. Guidelines for a structured transition process have therefore been recommended by the European League Against Rheumatism (EULAR) and the Paediatric Rheumatology European Society (PReS). However, implementation of these guidelines requires resources often not available in a busy clinical practice. AIMS: To assess the current practice of transitional care in Switzerland in relation to EULAR/PReS recommendations and to describe gaps and challenges in following the recommendations. METHODS: All paediatric Swiss rheumatology centres and their collaborating adult centres offering a transition service to adult care were invited to participate in this survey. The responsible paediatric and adult rheumatologist of each centre was interviewed separately using a structured manual addressing the EULAR/PReS transitional care recommendations. RESULTS: All 10 paediatric and 9 out of 10 adult rheumatologists agreed to participate. Centres varied in the number of patients in transition, from n = 0 to n = 111. The following EULAR/PReS recommendations were implemented and applied in most centres: continuity in the healthcare team, consultations focused on adolescents and young adults, joint consultations between the paediatric and adult rheumatologist, and access to the EULAR website. Only rarely did a centre have a written transition policy or evaluate their transitional care programme. The vast majority of the interviewees had no specific training in adolescent health. Most centres rated their transitional care performance as very good. CONCLUSION: Transition in Switzerland is not uniform and consequently the implementation of the EULAR/PReS recommendations is variable in Swiss rheumatology centres. Skills of healthcare professionals, continuity between clinical settings, size of the centres, and hospital focus on the needs of adolescents and young adults may represent key predictors of successful transitional care for patients with chronic rheumatic diseases. Future studies should examine these variables.

The effect of exposure to radiofrequency electromagnetic fields on cognitive performance in human experimental studies: A protocol for a systematic review.

BACKGROUND: The World Health Organization (WHO) is currently assessing the potential health effects of exposure to radiofrequency electromagnetic fields (RF-EMFs) in the general and working population. Related to one such health effect, there is a concern that RF-EMFs may affect cognitive performance in humans. The systematic review (SR) aims to identify, summarize and synthesize the evidence base related to this question. Here, we present the protocol for the planned SR. OBJECTIVES: The main objective is to present a protocol for a SR which will evaluate the associations between short-term exposure to RF-EMFs and cognitive performance in human experimental studies. DATA SOURCES: We will search the following databases: PubMed, Embase, Web of Science, Scopus, and the EMF-Portal. The reference lists of included studies and retrieved review articles will be manually searched. STUDY ELIGIBILITY AND CRITERIA: We will include randomized human experimental studies that assess the effects of RF-EMFs on cognitive performance compared to no exposure or lower exposure. We will include peer-reviewed articles of any publication date in any language that report primary data. DATA EXTRACTION AND ANALYSIS: Data will be extracted according to a pre-defined set of forms developed and piloted by the review author team. To assess the risk of bias, we will apply the Rating Tool for Human and Animal Studies developed by NTP/OHAT, supplemented with additional questions relevant for cross-over studies. Where sufficiently similar studies are identified (e.g. the heterogeneity concerning population, exposure and outcome is low and the studies can be combined), we will conduct random-effects meta-analysis; otherwise, we will conduct a narrative synthesis. ASSESSMENT OF CERTAINTY OF EVIDENCE: The certainty of evidence for each identified outcome will be assessed according to Grading of Recommendations Assessment, Development, and Evaluation (GRADE). Performing the review according to this protocol will allow the identification of possible effects of RF-EMFs on cognitive performance in humans. The protocol has been registered in PROSPERO, an open-source protocol registration system, to foster transparency.

Effects of 2.45 GHz Wi-Fi exposure on sleep-dependent memory consolidation.

Studies have reported that exposure to radiofrequency electromagnetic fields (RF-EMF) emitted by mobile telephony might affect specific sleep features. Possible effects of RF-EMF emitted by Wi-Fi networks on sleep-dependent memory consolidation processes have not been investigated so far. The present study explored the impact of an all-night Wi-Fi (2.45 GHz) exposure on sleep-dependent memory consolidation and its associated physiological correlates. Thirty young males (mean ± standard deviation [SD]: 24.1 ± 2.9 years) participated in this double-blind, randomized, sham-controlled crossover study. Participants spent five nights in the laboratory. The first night was an adaptation/screening night. The second and fourth nights were baseline nights, each followed consecutively by an experimental night with either Wi-Fi (maximum: psSAR10g = <25 mW/kg; 6 min average: <6.4 mW/kg) or sham exposure. Declarative, emotional and procedural memory performances were measured using a word pair, a sequential finger tapping and a face recognition task, respectively. Furthermore, learning-associated brain activity parameters (power spectra for slow oscillations and in the spindle frequency range) were analysed. Although emotional and procedural memory were not affected by RF-EMF exposure, overnight improvement in the declarative task was significantly better in the Wi-Fi condition. However, none of the post-learning sleep-specific parameters was affected by exposure. Thus, the significant effect of Wi-Fi exposure on declarative memory observed at the behavioural level was not supported by results at the physiological level. Due to these inconsistencies, this result could also be a random finding.

RF-EMF exposure effects on sleep - Age doesn't matter in men!

BACKGROUND: Although there are several human experimental studies on short-term effects of radiofrequency electromagnetic fields (RF-EMF) on sleep, the role of effect modification by sex or age in this context has not yet been considered. In an earlier study, we observed sex differences in RF-EMF effects in elderly subjects. The present study investigated possible RF-EMF effect modifications by age in men. METHODS: Data available for the present analysis come from three double-blind, randomized cross-over studies, in which effects of different RF-EMF exposure signals on sleep were investigated in young [sample 1: 25.3 (mean) ± 2.6 (SD) years; sample 2: 25.4 ± 2.6 years; n = 30, respectively] and older (69.1 ± 5.5 years; n = 30) healthy male volunteers. Studies comprised a screening/adaptation night followed by nine experimental nights at two-week intervals. RF-EMF exposure effect modifications by age were analysed for two different exposure signals (GSM900 at 2 W/kg, TETRA at 6 W/kg), each compared to a sham exposure. Polysomnography, during which the exposure signals were delivered by a head worn antenna, as well as sleep staging were performed according to the AASM standard. Four subjective and 30 objective sleep parameters were statistically analysed related to possible RF-EMF effects. RESULTS: Comparisons of sleep parameters observed under sham exposure revealed highly pronounced physiological differences between young and elderly men. A consistent exposure effect in both age groups was found for a shorter latency to persistent sleep under TETRA exposure reflecting a sleep-promoting effect. Exposure effect modifications by age were observed for two of the four self-reported sleep parameters following GSM900 exposure and for arousals during REM sleep under TETRA exposure. CONCLUSIONS: As effects of a short-term all-night RF-EMF exposure on sleep occurred only sporadically in young and elderly men, it seems that age doesn't matter in this respect. However, as long as there are no corresponding data from young healthy women that would allow a comparison with the data from elderly women, this assumption cannot be conclusively verified. Nevertheless, the present results are not indicative of any adverse health effects.

Spending the night next to a router - Results from the first human experimental study investigating the impact of Wi-Fi exposure on sleep.

BACKGROUND: The use of wireless telecommunication systems such as wireless fidelity (Wi-Fi)-enabled devices has steadily increased in recent years. There are persistent concerns that radiofrequency electromagnetic field (RF-EMF) exposure might affect health. Possible effects of RF-EMF exposure on human sleep were examined with regard to mobile phones and base stations, but not with regard to Wi-Fi exposure. OBJECTIVES: The present double-blind, sham-controlled, randomized, fully counterbalanced cross-over study addressed for the first time the question whether a whole night Wi-Fi exposure has an effect on sleep. METHODS: Thirty-four healthy young male subjects (mean ± SD: 24.1 ± 2.9 years) spent five nights in the sleep laboratory. A screening and adaptation night was followed by two experimental nights. Each of the experimental nights was preceded by a baseline night. Sleep was evaluated at the subjective level by a questionnaire and at the objective level (macro- and microstructure) by polysomnography. Either 2.45 GHz Wi-Fi (max psSAR10g of 6.4 mW/kg) or sham signals were delivered by a newly developed head exposure facility. RESULTS: Results showed no statistically significant acute effects of a whole-night Wi-Fi exposure on subjective sleep parameters as well as on parameters characterizing the macrostructure of sleep. Analyses of the microstructure of sleep revealed a reduction in global EEG power in the alpha frequency band (8.00-11.75 Hz) during NREM sleep under acute Wi-Fi exposure compared to sham. DISCUSSION: The results of the present human experimental study are well in line with several other neurophysiological studies showing that acute RF-EMF exposure has no effect on the macrostructure of sleep. The slight physiological changes in EEG power observed under Wi-Fi exposure are neither reflected in the subjective assessment of sleep nor at the level of objective measurements. The present results are not indicative of a sleep disturbing effect of Wi-Fi exposure.

Design and Dosimetric Analysis of an Exposure Facility for Investigating Possible Effects of 2.45 GHz Wi-Fi Signals on Human Sleep.

A new head exposure system for double-blind provocation studies investigating possible effects of 2.45 GHz Wi-Fi exposure on human sleep was developed and dosimetrically analyzed. The exposure system includes six simultaneously radiating directional antennas arranged along a circle (radius 0.6 m) around the test subject's head, and enables a virtually uniform head exposure, i.e. without any preferred direction of incidence, during sleep. The system is fully computer-controlled and applies a real wireless local area network (WLAN) signal representing different transmission patterns as expected in real WLAN scenarios, i.e. phases of "beacon only" as well as phases of different data transmission rates. Sham and verum are applied in a double-blind crossover study design and all relevant exposure data, i.e. forward and reverse power at all six antenna inputs, are continuously recorded for quality control. For a total antenna input power (sum of all antennas) of 220 mW, typical specific absorption rate (SAR) in cortical brain regions is approximately 1-2 mW/kg (mass average SAR over respective brain region), which can be seen as a realistic worst-case exposure level in real WLAN scenarios. Taking into account variations of head positions during the experiments, the resulting exposure of different brain regions may deviate from the given average SAR levels up to 10 dB. Peak spatial 10 g average SAR in all brain and all head tissues is between 1.5-3.5 and 10.4-25 mW/kg, respectively. Bioelectromagnetics. © 2020 Bioelectromagnetics Society.

An experimental study on effects of radiofrequency electromagnetic fields on sleep in healthy elderly males and females: Gender matters!

BACKGROUND: Results from human experimental studies investigating possible effects of radiofrequency electromagnetic fields (RF-EMF) on sleep are heterogeneous. So far, there is no study on possible sex-differences in RF-EMF effects. OBJECTIVES: The present study aimed at analyzing differences in RF-EMF effects on the macrostructure of sleep between healthy elderly males and females. METHODS: With a double-blind, randomized, sham-controlled cross-over design effects of two RF-EMF exposures (GSM900 and TETRA) on sleep were investigated in samples of 30 elderly healthy male and 30 healthy elderly female volunteers. Participants underwent each of the three exposure conditions on three occassions following an individually randomized order resulting in a total of nine study nights per participant. Exposure was delivered for 30 min prior to sleep and for the whole night (7.5 h) by a head worn antenna specifically designed for the projects. The peak spatial absorption rate averaged over time in head tissues (psSAR10g) was 6 W/kg for TETRA and 2 W/kg for GSM900. Thirty variables characterising the macrostructure of sleep and arousals as well as four subjective sleep variables were considered for statistical analyses. RESULTS: Multivariate analyses revealed that exposure to GSM900 and/or TETRA resulted in a significant reduction in arousals, a shorter latency to sleep stage N3, and a shorter self-reported time awake after sleep in both males and females. Exposure effects depending on sex (significant interactions) were observed. Latency to sleep stage R was shorter in females and tended to be longer in males under both exposures. Latency to stage N3 was shorter in females under TETRA exposure and almost not affected in males. The time awake within the sleep period under TETRA exposure was shorter in females and only slightly longer in males. Under GSM exposure, the self-rated total sleep time tended to be longer in females and to be shorter in males. Finally, the number of awakenings was lower only in females and tended to be higher in males under GSM exposure. DISCUSSION: With regard to RF-EMF effects on human sleep it seems that gender matters since GSM900 and TETRA led to significantly more exposure effects in females. Regardless of gender, none of the observed changes is indicative of a sleep disturbing effect of RF-EMF exposure. Observed effects might be mediated by skin related thermoregulatory mechanisms.

Dosimetric analysis of hands exposure during handling of strong permanent magnets.

Workers in a production line for synchronous motors occasionally reported tingling sensations or a feeling of numbness in their hands when handling strong permanent magnets. As the magnetic flux density (B) and its gradients along and close to the surface of the permanent magnets were expected to be comparably high and the movements of the workers' hands may therefore cause relevant induction inside the tissue, a detailed dosimetric analysis of the in situ electric field inside the hands (Ei) of the workers was carried out. The time derivate of the magnetic flux density (dB/dt) occurring along the hands was determined based on time domain measurements using a specially developed 'measurement glove' containing 12 Hall sensors. Based on these measurement results temporal peak electric field strength (Ei) induced inside a newly developed high resolution anatomical hand models were numerically computed, using the scalar potential finite difference (SPFD) method. The highest measured dB/dt along the palmar side of the hand was 51.2 T s-1. The corresponding worst case temporal peak value of the maximum of the Ei averaged over 2 × 2 × 2 mm3 in soft tissue was 2.0 V m-1, which is a factor of 1.8 higher than the applicable exposure limit value, but still below the range of 3.8-6.2 V m-1 which is presently assumed the range of lowest stimulation threshold for peripheral nerves. Our analysis did therefore not provide an indication that the perception reported by the workers are due to tissue stimulation in the sense of provoking action potentials.

Dosimetric issues with simplified homogeneous body models in low frequency magnetic field exposure assessment.

A simplified procedure, using circular disk models with homogeneous electric conductivity as representations for different body parts, has been proposed recently by product standard IEC 62822-3 for the assessment of magnetic field exposure in proximity to current-carrying conductors of welding equipment. Based on such simplified models, worst case coupling coefficients CCEi(I), i.e. maximum induced electric field strength, normalised for current and frequency, for body parts at different distances d to straight single and double wire arrangements, as well as rectangular loop-shaped current paths are tabulated in the standard. In this work we compared CCEi(I) values obtained by numerical computations with detailed anatomical models of the hand/forearm with the corresponding values given in IEC 62822-3 for current-carrying single wire conductors along the forearm at distances d = 30, 50 and 100 mm, respectively. Our results clearly indicated that the CCEi(I) given in the standard may substantially underestimate the actual exposure. Using average values for tissue conductivities the observed extent of underestimation was up to 8.9 dB (factor 2.79) and may be even higher for worst case combinations of tissue conductivities. The reasons for this substantial underestimation are the oversimplified geometry, i.e. the circular disk does not reflect anatomical constrictions of the induction area present in realistic hand/forearm geometries, as well as the missing conductivity contrast between different tissues in the homogeneous disk models. Results of exposure assessment and corresponding minimum distances to components of welding equipment obtained by the simplified disk model approach suggested by IEC 62822-3 should therefore be considered with caution.

Benchmark of different assessment methods for non-sinusoidal magnetic field exposure in the context of European Directive 2013/35/EU.

For the assessment of non-sinusoidal magnetic fields the European EMF Directive 2013/35/EU specified the Weighted Peak Method in Time Domain (WPM-TD) as the reference method. However, also other scientifically validated methods are allowed, provided that they lead to approximately equivalent and comparable results. In the non-binding guide for practical implementation of 2013/35/EU three methods alternative to the WPM-TD are described, i.e. the Weighted Peak Method in Frequency Domain (WPM-FD), the Multiple Frequency Rule (MFR), and an alternative Time Domain Assessment Method (TDAM). In this paper the results of a benchmark comparison of these assessment methods, based on 12 different time domain signals of magnetic induction, measured close to real devices and nine additional generic waveforms, are presented. The results demonstrated that assessments obtained with WPM-TD and WPM-FD can be considered approximately equivalent (maximum deviation 3.4 dB). The MFR systematically overestimates exposure, due to its inherently conservative definitions. In contrast, the TDAM significantly and systematically underestimates exposure up to a factor of 22 (26.8 dB) for the considered waveforms. The main reasons for this exposure underestimation by the TDAM are the introduction of an inappropriate time averaging, and the fact that the characteristic time parameter τ p,min, describing the minimum duration of all field changes dB/dt of the waveform is derived independently from the extent of the field change in the definitions of the TDAM. Consequently, we recommend not to use the TDAM as presently published in the non-binding guide to 2013/35/EU, as its application would be in contradiction with the underlying aim of 2013/35/EU, i.e. a harmonised level of occupational safety with respect to exposure to electromagnetic fields.

Systematic Numerical Analysis of Magnetic Field Partial Body Exposure and Comparison With Occupational Exposure Limit Values According to European Directive 2013/35/EU.

According to European Directive 2013/35/EU, exposure limit values for protection against sensory and health effects are met if external electric or magnetic fields are below corresponding low and high action levels for head, trunk and limb exposure, respectively. In order to verify this assumption even for more realistic exposure situations deviating from strictly uniform fields, systematic numerical computations using anatomical body models exposed to worst-case magnetic field gradients in different body regions are conducted. Applying magnetic fields according to low action level to the head and high action level to trunk and limbs at the same time results in slightly increased in situ electric field strengths in central nervous system tissues, compared to uniform exposure at the low action level. The extent of this increase depends on field orientation, field gradient (slope from low to high action level), and relative position between body region and field gradient. While this increase does not lead to conflicts with the exposure limit values for frequencies of 50 Hz and higher, violation of corresponding exposure limit values could be observed at 16.67 Hz.

Inconsistency of a recently proposed method for assessing magnetic field exposure for protection against peripheral nerve stimulation in occupational situations.

A non-binding guide to practical implementation of European Directive 2013/35/EU concerning the limitation of occupational exposure against electromagnetic fields has been published recently. With regard to exposure assessment this guide proposes practically applicable assessment methods for non-uniform and non-sinusoidal environmental electric and magnetic fields, respectively. For non-sinusoidal magnetic fields in the low frequency range this guide proposes a time domain assessment (TDA) method, claimed to reduce the overestimation of exposure inherent to other assessment methods while being based on fundamental physiological principles regarding nerve stimulation. In the present paper we demonstrate that the proposed TDA method is not consistent with the obvious underlying principles of directive 2013/35/EU. Based on practically relevant waveforms and general considerations it can be shown that external magnetic fields may be deemed compliant by the TDA method although the underlying exposure limit values defined in 2013/35/EU may be exceeded. We therefore strongly recommend that the TDA method is removed from the guide for implementing 2013/35/EU as soon as possible.