Brain & Nervous System

Effects of short- and long-term pulsed radiofrequency electromagnetic fields on night sleep and cognitive functions in healthy subjects.

Fritzer G et al. · 2007

Effects of mobile phone electromagnetic fields on an auditory order threshold task

Cinel C, Boldini A, Russo R, Fox E · 2007

Changes in heart rate variability among RF plastic sealer operators.

Wilén J, Wiklund U, Hörnsten R, Sandström M. · 2007

The study aimed to investigate changes in heart rate variability among RF plastic sealer operators. Researchers found significantly increased total HRV and VLF power during nighttime in RF operators compared to a control group. This finding, together with a previous finding of lower nighttime heart rate, indicates a relative increase in parasympathetic cardiac modulation in RF operators.

The effect of authentic metallic implants on the SAR distribution of the head exposed to 900, 1800 and 2450 MHz dipole near field.

Virtanen H, Keshvari J, Lappalainen R. · 2007

Researchers examined the effect of authentic passive metallic implants in the head region. A half-wave dipole antenna was used as an exposure source and SAR in the near field was studied numerically at GSM (900 and 1800 MHz) and UMTS (2450 MHz) frequencies. Results indicate some implants under very rare exposure conditions may cause a notable enhancement in peak mass averaged SAR.

Cellular telephone use and time trends in brain tumour mortality in Switzerland from 1969 to 2002.

Roosli M, Michel G, Kuehni CE, Spoerri A · 2007

Researchers used Swiss national mortality registry data from 1969 to 2002 to calculate age-standardized brain tumour mortality rates per 100,000 person-years. The study period was split before and after 1987 when analogue mobile technology was introduced. Over the whole period, mortality increased significantly in older age groups (60-74 and 75+ years) but not in younger groups. From 1987 onward, brain tumour mortality rates were relatively stable in all age groups.

Dielectric properties of porcine cerebrospinal tissues at microwave frequencies: in vivo, in vitro and systematic variation with age.

Peyman A, Holden SJ, Watts S, Perrott R, Gabriel C · 2007

The dielectric properties of pig cerebrospinal tissues were measured in vivo and in vitro in the frequency range of 50 MHz-20 GHz. White matter and spinal cord showed significant variation as a function of animal age while no age-related variations were recorded for grey matter. The in vitro study included tissue from pigs weighing approximately 10, 50, and 250 kg to examine variation with age. Total combined measurement uncertainty was calculated at each frequency point and reported over representative frequency regions. Comparisons were made between the in vivo and in vitro data and with literature from the past decade.

Altered cortical excitability in subjectively electrosensitive patients: results of a pilot study.

Landgrebe M et al. · 2007

Researchers measured cortical excitability parameters using transcranial magnetic stimulation in 23 subjectively electrosensitive patients and two control groups totaling 49 participants with varying levels of unspecific health complaints. Electrosensitive patients showed reduced intracortical facilitation compared to both control groups. Motor thresholds and intracortical inhibition were unaffected in electrosensitive patients relative to controls. The authors suggest that altered central nervous system function may account for symptom manifestation in subjectively electrosensitive patients.

Mobile phone use and risk of glioma in 5 North European countries.

Lahkola A et al. · 2007

Researchers conducted a population-based case-control study of 1,522 glioma patients and 3,301 controls. Regular mobile phone use was not associated with increased glioma risk (OR = 0.78, 95% CI: 0.68–0.91). No significant associations were found for duration of use, years since first use, cumulative calls, or cumulative hours, though a linear trend showed a small increase per 100 hours of cumulative use (OR = 1.006 (1.002, 1.010) per 100 hr). For more than 10 years of use on the same side as the tumor, a borderline significant increased odds ratio of 1.39 (95% CI: 1.01–1.92) was observed, while use on the opposite side showed no increase (OR = 0.98, 95% CI: 0.71–1.37).

Effects of pulsed and continuous wave 902 MHz mobile phone exposure on brain oscillatory activity during cognitive processing.

Krause CM, Pesonen M, Haarala Bjornberg C, Hamalainen H. · 2007

Researchers recruited two groups of 36 male participants each, one performing an auditory memory task and the other a visual working memory task under six exposure conditions. The study aimed to partially replicate earlier work and investigate effects of mobile phone EMF on event-related desynchronisation/synchronisation EEG responses during cognitive processing. EMF exposure produced modest effects on alpha band oscillatory responses but no effects on behavioural measures. The EEG effects were varying, unsystematic, and inconsistent with previous reports.

[Cell Phones and Risk of brain and acoustic nerve tumours: the French INTERPHONE case-control study.]

Hours M et al. · 2007

Cases were histologically confirmed or based on radiological images, and controls were matched for gender, age, and residence, drawn from electoral rolls. Detailed exposure information was collected via face-to-face interviews, and conditional logistic regression estimated odds ratios. Regular cell phone use was not associated with increased risk of neuroma, meningioma, or glioma. A tendency for increased glioma risk was observed among the heaviest users, but the study had limited statistical power and results need verification in the international analysis.

Long-term use of cellular phones and brain tumours - increased risk associated with use for > 10 years.

Hardell LO et al. · 2007

Researchers reviewed two cohort studies and 16 case-control studies on cellular phone use and brain tumour risk, focusing on use for 10 or more years and ipsilateral exposure. The cohort study was considered of limited value due to methodological shortcomings, and most case-control results were based on low numbers. Four case-control studies found an association with acoustic neuroma for at least 10 years' use, while six studies reported increased odds ratios for malignant brain tumours, especially for ipsilateral exposure. A meta-analysis found ipsilateral cell phone use for 10 or more years yielded an odds ratio of 2.4 for acoustic neuroma and 2.0 for glioma.

Pooled analysis of two Swedish case-control studies on the use of mobile and cordless telephones and the risk of brain tumours diagnosed during 1997-2003.

Hansson Mild K, Hardell L, Carlberg M. · 2007

The study presents a pooled analysis of two case-control studies on the association of brain tumours with mobile phone use. Use of analogue cellular phones increased the risk for acoustic neuroma by 5% per 100 hours of use. The risk increased for astrocytoma grade III-IV with latency period, with highest estimates for more than 10 years since first use. Risk increased per year of use for analogue phones by 10%, digital phones by 11%, and cordless phones by 8%. For all studied phone types, odds ratios for brain tumours, mainly acoustic neuroma and malignant brain tumours, increased with latency period, especially for astrocytoma grade III-IV.

Radio-frequency radiation exposure from AM radio transmitters and childhood leukemia and brain cancer.

Ha M, Im H, Lee M, Kim HJ, Kim BC, Gimm YM, Pack JK. · 2007

Researchers selected leukemia and brain cancer patients under age 15 and matched controls from 14 South Korean hospitals using the Medical Insurance Data System. Exposure to RFR from 31 AM transmitters of at least 20 kW was estimated using a GIS-based prediction program calibrated with measurements. The odds ratio for all leukemia was 2.15 for children within 2 km of the nearest transmitter versus those beyond 20 km. For total RFR exposure, lymphocytic leukemia odds ratios were 1.39 and 1.59 in the second and third quartiles versus the lowest, and brain cancer was not associated with AM RFR.

Electroencephalographic, personality, and executive function measures associated with frequent mobile phone use.

Arns M, Van Luijtelaar G, Sumich A, Hamilton R, Gordon E. · 2007

Researchers used standardized data from the Brain Resource International Database to examine the relationship between mobile phone usage, personality, and brain function in 300 participants. The findings suggest a subtle slowing of brain activity related to mobile phone use that is not explained by personality differences. These changes are still within normal physiological ranges. Better executive function in mobile phone users may reflect more focused attention, possibly associated with a cognitive training effect from frequently making phone calls in distracting places. Participants were divided into three groups based on the frequency and duration of their mobile phone usage.

Mobile phone induced sensorineural hearing loss.

Al-Dousary SH. · 2007

The study aimed to observe mobile phone induced sensorineural hearing loss. A case of sensorineural hearing loss due to Global System for Mobile Communications mobile phone use in a 42-year-old male was reported.

Exposure to cell phone radiation up-regulates apoptosis genes in primary cultures of neurons and astrocytes

Zhao TY, Zou SP, Knapp PE. · 2007

Researchers exposed primary cultured neurons and astrocytes to GSM cell phone emissions at 1900 MHz for 2 hours. Neurons showed up-regulation of caspase-2, caspase-6, and Asc genes in both 'on' and 'stand-by' modes. Astrocytes showed up-regulation of the same genes only in 'on' mode and also up-regulated the Bax gene.

Mobile phone emission modulates interhemispheric functional coupling of EEG alpha rhythms

Vecchio F et al. · 2007

Ten subjects underwent two EEG recordings separated by one week in a crossover double-blind paradigm. The mobile phone was held on the left side of the head by a modified helmet. Each session lasted 45 minutes with real GSM exposure in one session and sham in the other. GSM stimulation modulated interhemispheric frontal and temporal coherence at alpha2 and alpha3 bands compared to sham.

Electromagnetic fields produced by GSM cellular phones and heart rate variability

Parazzini M et al. · 2007

Researchers exposed 26 healthy young volunteers to 900 MHz GSM phone radiation and sham exposure in separate double-blind sessions. A rest-to-stand protocol assessed autonomic nervous system function during rest and after sympathetic activation. No statistically significant effect of EMF exposure was found on the main RR mean or most other heart rate variability parameters. A weak interaction between some time and frequency domain HRV parameters and RF exposure was observed around the sympathetic response to standing.

Effect of whole-body exposure to high-frequency electromagnetic field on the brain cortical and hippocampal activity in mouse experimental model

Barcal J, Vozeh F · 2007

ECoG evaluation showed a distinct shift to lower frequency components in wild type mice but only gentle differences in Lurcher mutant mice. Hippocampal rhythmicity showed gentle changes with increase of higher frequencies and changes in theta oscillations in both healthy and mutant mice.

Neurobehavioral effects among inhabitants around mobile phone base stations

Abdel-Rassoul G et al. · 2007

A cross-sectional study enrolled 85 residents living near a mobile phone base station in Egypt and 80 matched controls. Exposed residents reported significantly higher rates of headache, memory changes, dizziness, tremors, depressive symptoms, and sleep disturbance than controls. On neurobehavioral testing, exposed residents performed worse on a test of attention and short-term auditory memory but better on tests of visuomotor speed and attention. Residents living opposite the station performed worse on a problem-solving test than those living under the station. Measured radiofrequency radiation levels were below the allowable standard.

Neurophysiologic effects at low level 1.8 GHz radiofrequency field exposure: a multiparametric approach on freely moving rats.

Crouzier D et al. · 2007

Researchers exposed freely moving rats for 24 hours to a 1.8 GHz GSM radiofrequency signal at low power density. The study tracked acetylcholine release in the hippocampus, EEG, EMG, and subcutaneous temperature, and also analyzed brain lipid extracts using NMR after the animals were sacrificed. No significant changes in any measured parameter were observed under radiofrequency exposure, and the NMR study also failed to show any effect.

Adaptation of human brain bioelectrical activity to low-level microwave.

Bachmann M et al. · 2007

Researchers studied how the human brain's bioelectrical activity adapted to low-level microwave exposure in a group of 14 healthy volunteers. The volunteers were exposed to 450 MHz microwave radiation modulated at 40 Hz frequencies, with a field power density at the scalp of 0.16 mW/cm(2). Results showed that an initial increase in EEG power was compensated and even overcompensated, with adaptation effects apparent in alpha and beta rhythms.

A method for detecting the effect of magnetic field on activity changes of neuronal populations of Morimus funereus (Coleoptera, Cerambycidae).

Todorović D, Kalauzi A, Prolić Z, Jović M, Mutavdzić D. · 2007

Researchers measured the influence of a static magnetic field at 2 mT on neuronal population activity in eight individuals of the endangered insect species Morimus funereus. Five minutes of exposure produced excitatory effects in 5 of 8 individuals and inhibitory effects in 3 of 8 individuals in the antennal lobe. When reversibility was analyzed, the induced effects were prevailingly irreversible: 7 of 8 for the neuronal population and 6 of 8 for the nearest neuron.

Effects of static magnetic fields on the voltage-gated potassium channel currents in trigeminal root ganglion neurons.

Shen JF, Chao YL, Du L. · 2007

Researchers used whole-cell patch-clamp experiments on acute dissociated rat trigeminal root ganglion neurons to study how static magnetic fields affect voltage-gated potassium channel currents. The study evaluated the effects of moderate-intensity static magnetic fields on two types of voltage-gated potassium channel currents, called IK,A and IK,V. A 125 mT static magnetic field altered the inactivation rate and velocity of both channel currents, while activation properties showed no significant change.

Fifty Hertz electromagnetic field exposure stimulates secretion of beta-amyloid peptide in cultured human neuroglioma.

Del Giudice E et al. · 2007

Researchers tested whether low-frequency electromagnetic field exposure could affect amyloid-related processes in cultured cells. The study exposed H4 neuroglioma cells, which overexpress human mutant amyloid precursor protein, to a 3.1 mT 50 Hz electromagnetic field. Overnight exposure led to a significant increase in amyloid-beta peptide secretion, including the isoform Abeta 1-42, without affecting cell survival.