Medical/biological study (experimental study)

The alteration of spontaneous low frequency oscillations caused by acute electromagnetic fields exposure med./bio.

By: Lv B, Chen Z, Wu T, Shao Q, Yan D, Ma L, Lu K, Xie Y

Published in: Clin Neurophysiol 2014; 125 (2): 277-286

Aim of study (acc. to author)

To investigate the effects of exposure to a Long Term Evolution (LTE) signal on the resting state brain activity in humans.

Background/further details

18 subjects were exposed or sham exposed in 2 sessions (cross-over study). The two sessions were seperated by one day. Functional magnetic resonance imaging (fMRI) was performed before and after the exposure/sham exposure period to measure the resting state brain activity . Additionally, before the exposure/sham exposure period a structural magnetic resonance imaging was performed to determine the specific absorption rate.

Endpoint

effects on the neurological system: resting state brain activity

Exposure

- 2.573 GHz
- mobile communications
- mobile phone
- LTE

Exposure	Parameters
Exposure 1: 2.573 GHz Exposure duration: continuous for 30 minutes	SAR: 2.18 W/kg maximum (1 g) (subject A) SAR: 2.36 W/kg maximum (1 g) (subject B) SAR: 0.9 W/kg spatial average (10 g) (subject A) SAR: 1.07 W/kg spatial average (10 g) (subject B)

General information

Reference article: IEEE Standard 1528. IEEE recommended practice for determining the peak spatial average specific absorption rate (SAR) in the human head from wireless communications devices: measurement techniques. NJ, USA: Piscataway; 2003.

Exposure 1

Main characteristics

Frequency	2.573 GHz
Type	electromagnetic field
Charakteristic	near field
Exposure duration	continuous for 30 minutes

Exposure setup

Exposure source	dipole antenna
Distance between exposed object and exposure source	1 cm
Setup	experiment was carried out in an anechoic chamber; dipole antenna was placed on the right side with a distance of 1 cm to the ear; spacing distance between antenna and ear was restricted by white foam, length of the dipole was perpendicular to the head length, subjects sat comfortably in a chair with touching the foam and were quiet
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	2.18 W/kg	maximum	measured	1 g	subject A
SAR	2.36 W/kg	maximum	measured	1 g	subject B
SAR	0.9 W/kg	spatial average	measured	10 g	subject A
SAR	1.07 W/kg	spatial average	measured	10 g	subject B

Exposed system:

human
partial body: right ear

Methods Endpoint/measurement parameters/methodology

effects on the neurological system: resting state brain activity via BOLD (blood-oxygen-level dependent) response (fMRI): absolute strength of spontaneous fluctuations (amplitude of low frequency fluctuation (ALFF), calculation via power spectrum), relative contribution of specific spontaneous fluctuations (fractional amplitude of low frequency fluctuations (fALFF), ratio of ALFF in a predefined frequency range to the ALFF over the entire detectable frequency range) (magnetic resonance imaging)

Investigated system:

investigation on living organism

Investigated organ system:

brain/CNS

Time of investigation:

before exposure
after exposure

Main outcome of study (acc. to author)

After exposure, a decreased ALFF amplitude was found in the left and right superior temporal gyrus, in the left middle temporal gyrus, in the right medial frontal gyrus and in the right paracentral lobule in comparison to sham exposure conditions. Additionally, in exposed subjects, a decreased fALFF amplitude was detected in the right medial frontal gyrus and right paracentral lobule compared to sham exposed subjects.
The data indicate that exposure to a Long Term Evolution (LTE) signal modulated the resting state brain activity in humans.

Study character:

medical/biological study
experimental study
full/main study
double-blind study, cross-over study, randomized

Study funded by

China Postdoctoral Science Foundation (CPSF), China
National Key Basic Research Project, China
National Natural Science Foundation (NSFC), China

Yang L et al. (2017): Long-Term Evolution electromagnetic fields exposure modulates the resting state EEG on alpha and beta bands
Lv B et al. (2014): Whole brain EEG synchronization likelihood modulated by long term evolution electromagnetic fields exposure
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