Study type: Medical/biological study (experimental study)

Using the nonlinear control of anesthesia-induced hypersensitivity of EEG at burst suppression level to test the effects of radiofrequency radiation on brain function. med./bio.

Published in: Nonlinear Biomed Phys 2009; 3 (1): 1-18

Aim of study (acc. to author)

To study the effects of radiofrequency irradiation from the GSM mobile phone on the electrical activity of a pig brain at exposure levels above those accepted for human testing.

Background/further details

The experiments were designed with two objectives: 1) to study the reactivity of the "EEG burst suppression pattern" (see below) to the electromagnetic field stimulation and 2) to study the changes in the EEG signal due to continuous high power electromagnetic field exposure.
Eleven pigs were anaesthetised to the level where "burst-suppression pattern" appears in the EEG. At this level of anaesthesia both human subjects and animals show high sensitivity to external stimuli which produce EEG bursts during suppression (the low-amplitude EEG abruptly switches to very high amplitude bursts). This switching can be triggered by very minor stimuli and the phenomenon has been described as "hypersensitivity".
In the first phase of the experiment electromagnetic field stimulation (as external stimulus) was randomly switched on and off and the relation between EEG bursts and electromagnetic field stimulation onsets and endpoints were studied. In the second phase a continuous radiofrequency stimulation at 31 W/kg was applied for 10 minutes.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 890 MHz
Modulation type: pulsed
Exposure duration: 20 -30 min
  • power: 200 W peak value
  • SAR: 7.3 W/kg average over mass (10 g) (during part of phase 1)
  • SAR: 31 W/kg maximum (10 g) (during part of phase 1 and during phase 2)

Exposure 1

Main characteristics
Frequency 890 MHz
Type
Exposure duration 20 -30 min
Modulation
Modulation type pulsed
Additional info

during phase 1 power switched on/off randomly for 1 - 10 s ; duration of phase 1 = 10 - 20 min during phase 2 continuous exposure for 10 min

Exposure setup
Exposure source
Setup antenna fixed to the pig's head
Parameters
Measurand Value Type Method Mass Remarks
power 200 W peak value - - -
SAR 7.3 W/kg average over mass - 10 g during part of phase 1
SAR 31 W/kg maximum - 10 g during part of phase 1 and during phase 2

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • before exposure
  • during exposure
  • after exposure

Main outcome of study (acc. to author)

The exposure to 890 MHz electromagnetic field stimulation at 31 W/kg increased the subcutaneous temperature of the pigs by about 1.6°C and the heart rate by 14.2 beats per minute in a group of six anaesthetised pigs. No significant changes were observed in the EEG activity of the animals although several EEG signal analysis methods were applied. In a group of ten pigs, anaesthetized to the level where the EEG burst suppression pattern occurs, no correlation was found between switching on or off the electromagnetic field stimulation and triggering of the bursts.
In none of the pigs there was any sign of the "hypersensitive nonlinear burst suppression control system". Thus, the data indicate that the radiofrequency exposure does not produce sensory stimulation of somatosensory, auditory or visual system or directly affect the brain so as to produce EEG bursts during suppression. The slow rise in temperature at very high radiofrequency intensity suggests that there is an effect also in brain tissue, but this is not appropriate, intensive or abrupt enough to trigger the burst control system.

Study character:

Study funded by

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