Study type: Medical/biological study (experimental study)

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

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

Exposure

Exposure Parameters
Exposure 1: 2.573 GHz
Exposure duration: continuous for 30 minutes

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
Charakteristic
Exposure duration continuous for 30 minutes
Exposure setup
Exposure source
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:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
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:

Study funded by

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