Medical/biological study (experimental study)

Effect of low frequency modulated microwave exposure on human EEG: Individual sensitivity med./bio.

By: Hinrikus H, Bachmann M, Lass J, Karai D, Tuulik V

Published in: Bioelectromagnetics 2008; 29 (7): 527-538

Aim of study (acc. to author)

To evaluate the effect of modulated microwave exposure (450 MHz) on human EEG.

Background/further details

There were four exposure groups: 1) 7 Hz modulated microwaves (19 subjects), 2) 14 Hz and 21 Hz modulation (13 subjects), 3) 40 Hz and 70 Hz modulation (15 subjects), 4) 217 Hz and 1000 Hz modulation (19 subjects).

Endpoint

effects on the neurological system: EEG

Exposure

- microwaves

Exposure	Parameters
Exposure 1: 450 MHz Modulation type: pulsed Exposure duration: intermittent, 1 min off/1 min on, for 20 min	power density: 0.16 mW/cm² mean SAR: 0.303 W/kg peak value (1 g) (spatial peak value)
Exposure 2: 450 MHz Modulation type: pulsed Exposure duration: intermittent, 1 min off/1 min on, for 40 min	power density: 0.16 mW/cm² mean SAR: 0.303 W/kg peak value (1 g) (spatial peak value)

General information

Microwave exposure was identical to that in previous studies [Lass et al., 2002; Hinrikus et al., 2004] with the only exception that several different modulation frequencies were applied.

Exposure 1

Main characteristics

Frequency	450 MHz
Type	electromagnetic field
Exposure duration	intermittent, 1 min off/1 min on, for 20 min

Modulation

Modulation type	pulsed
Duty cycle	50 %
Repetition frequency	7 Hz

Exposure setup

Exposure source	monopole quarter-wave antenna (13 cm)
Distance between exposed object and exposure source	10 cm
Setup	The rod monopole antenna was located 10 cm from the skin on the left side of the head at a vertical angle of 45°.
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power density	0.16 mW/cm²	mean	measured	-	-
SAR	0.303 W/kg	peak value	calculated	1 g	spatial peak value

Measurement and calculation details

The spatial distribution of the power density was measured and the stability of the radiation level during the experiments was monitored using field strength meters. The average power density at the skin on the left side of the head was estimated from the measured calibration curves. The SAR was calculated using the FDTD computing method with the specific anthropomorphic mannequin (SAM) specified in IEEE Standard 1528-2003.

Exposure 2

Main characteristics

Frequency	450 MHz
Type	electromagnetic field
Exposure duration	intermittent, 1 min off/1 min on, for 40 min

Modulation

Modulation type	pulsed
Duty cycle	50 %
Additional info	Pulse rates of 14 and 21 Hz or 40 and 70 Hz or 217 and 1000 Hz were applied.

Exposure setup

Exposure source	same setup as exposure 1
Sham exposure	A sham exposure was conducted.
Additional info	Each modulation frequency of a pair was applied for the first or second 10 cycles (20 min) in random order. For each session, the exposure conditions (RF or sham) were randomly assigned between subjects.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power density	0.16 mW/cm²	mean	measured	-	-
SAR	0.303 W/kg	peak value	calculated	1 g	spatial peak value

Reference articles

Hinrikus H et al. (2004): Changes in human EEG caused by low level modulated microwave stimulation
Lass J et al. (2002): Effects of 7 Hz-modulated 450 MHz electromagnetic radiation on human performance in visual memory tasks

Exposed system:

human
partial body: head (left side)

Methods Endpoint/measurement parameters/methodology

effects on the neurological system: EEG (resting)

Investigated system:

investigation on living organism

Investigated organ system:

brain/CNS

Time of investigation:

before exposure
during exposure
after exposure

Main outcome of study (acc. to author)

The subjects significantly affected by modulated microwaves were found within all groups with the exception of the 1000 Hz modulated group. The findings showed that exposure caused significant increases in the EEG beta rhythms energy for 13- 31% of the subjects. In groups of subjects modulated at two different frequencies, in most cases the same subjects were sensitive at both modulation frequencies (except the fourth group at 1000 Hz modulation frequency).
Sensitivity of some subjects to microwave exposure is most likely related not to hypersensitivity of these individuals but to variability of the physiological state of the brain.
In conclusion, the data support the hypothesis that the effect of microwaves differs among individuals.

Study character:

medical/biological study
experimental study
full/main study
double-blind study

Study funded by

Estonian Science Foundation (ETF), Estonia

Smitha CK et al. (2015): Analysis of fractal dimension of EEG signals under mobile phone radiation
Roggeveen S et al. (2015): EEG changes due to experimentally induced 3G mobile phone radiation
Roggeveen S et al. (2015): Does the brain detect 3G mobile phone radiation peaks? An explorative in-depth analysis of an experimental study
Singh G (2014): The Effects of Mobile Phone Usage on Human Brain using EEG
Lv B et al. (2014): Whole brain EEG synchronization likelihood modulated by long term evolution electromagnetic fields exposure
Smitha CK et al. (2013): Effect of Mobile Phone Radiation on EEG
Perentos N et al. (2013): The alpha band of the resting electroencephalogram under pulsed and continuous radio frequency exposures
Hinrikus H et al. (2011): Higuchi's fractal dimension for analysis of the effect of external periodic stressor on electrical oscillations in the brain
Hinrikus H et al. (2009): Effect of modulated at different low frequencies microwave radiation on human EEG
Suhhova A et al. (2009): Effect of modulated microwave radiation on human EEG asymmetry
Hinrikus H et al. (2008): Effect of 7, 14 and 21 Hz modulated 450 MHz microwave radiation on human electroencephalographic rhythms
Suhhova A et al. (2008): Effect of Microwave Radiation on EEG Coherence
Croft RJ et al. (2008): The effect of mobile phone electromagnetic fields on the alpha rhythm of human electroencephalogram
Perentos N et al. (2008): The effect of GSM-like ELF radiation on the alpha band of the human resting EEG
Bachmann M et al. (2007): Individual changes in human EEG caused by 450 MHz microwave modulated at 40 and 70 Hz
Krause CM et al. (2007): Effects of pulsed and continuous wave 902 MHz mobile phone exposure on brain oscillatory activity during cognitive processing
Bachmann M et al. (2006): Integration of differences in EEG Analysis Reveals Changes in Human EEG Caused by Microwave
Hinrikus H et al. (2005): Non-Thermal Effect of Microwave Radiation on Human Brain
Bachmann M et al. (2005): Effect of 450 MHz Microwave Modulated with 217 Hz on Human EEG in Rest
Curcio G et al. (2005): Is the brain influenced by a phone call? An EEG study of resting wakefulness
Bachmann M et al. (2005): Non-linear analysis of the electroencephalogram for detecting effects of low-level electromagnetic fields
Hinrikus H et al. (2004): Changes in human EEG caused by low level modulated microwave stimulation
Krause CM et al. (2004): Effects of electromagnetic field emitted by cellular phones on the EEG during an auditory memory task: a double blind replication study
Huber R et al. (2002): Electromagnetic fields, such as those from mobile phones, alter regional cerebral blood flow and sleep and waking EEG
Krause CM et al. (2000): Effects of electromagnetic fields emitted by cellular phones on the electroencephalogram during a visual working memory task
Huber R et al. (2000): Exposure to pulsed high-frequency electromagnetic field during waking affects human sleep EEG
Krause CM et al. (2000): Effects of electromagnetic field emitted by cellular phones on the EEG during a memory task
Borbely AA et al. (1999): Pulsed high-frequency electromagnetic field affects human sleep and sleep electroencephalogram
Mann K et al. (1996): Effects of pulsed high-frequency electromagnetic fields on human sleep
Reiser H et al. (1995): The influence of electromagnetic fields on human brain activity

Effect of low frequency modulated microwave exposure on human EEG: Individual sensitivity med./bio.

Aim of study (acc. to author)

Background/further details

Endpoint

Exposure

General information

Exposure 1

Main characteristics

Modulation

Exposure setup

Parameters

Measurement and calculation details

Exposure 2

Main characteristics

Modulation

Exposure setup

Parameters

Reference articles

Methods Endpoint/measurement parameters/methodology

Main outcome of study (acc. to author)

Study funded by

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