Medical/biological study (experimental study)

Transient and cumulative memory impairments induced by GSM 1.8 GHz cell phone signal in a mouse model med./bio.

By: Ntzouni MP, Skouroliakou A, Kostomitsopoulos N, Margaritis LH

Published in: Electromagn Biol Med 2013; 32 (1): 95-120

Aim of study (acc. to author)

To examine memory impairments in mice exposed to a radiofrequency electromagnetic field.

Background/further details

In two experiments, three groups of mice were examined, respectively (n=8 per group): 1.) control group (in a seperate room), 2.) sham exposure + auditory stimulation (70 db) and 3.) exposure + auditory stimulation (70 db). Auditory stimulation was given to simulate human voice during cell phone operation.
The first experiment started after an acclimatization period from postnatal days 45 to 59. The exposure started at day 59 and lasted until day 125. During this exposure period, mice were tested thrice for potential memory impairments (testing 1a: postnatal days 59-63, testing 1b: postnatal days 88-92, testing 1c: postnatal days 121-125).
To test whether the potential memory impaiments were transient or permanent, the second experiment was performed. It started after an acclimatization period from postnatal days 45 to 69. Mice were exposed every day from postnatal days 76 to 130 and every second day from postnatal days 183 to 212. Before the first exposure period, mice were tested for potential memory impairments (testing 2a: postnatal days 69-73). Additionally, mice were tested for potential memory impairments during the first exposure period (testing 2b: postnatal days 100-104), twice between the exposure periods (testing 2c: postnatal days 140-144, testing 2d: postnatal days 168-172) and a fifth time after the second exposure period (testing 2e: postnatal days 213-217).

Endpoint

cognitive/behavioral endpoints: spatial and non-spatial memory performance

Exposure

- 1,800 MHz
- mobile communications
- mobile phone
- GSM
- co-exposure

Exposure	Parameters
Exposure 1: 1,800 MHz Exposure duration: 90 min/day every day or every second day for up to 83 days (detailed description in "aim of study")	SAR: 0.11 W/kg effective value electric field strength: 12 V/m average over time (within the cages)

Exposure 1

Main characteristics

Frequency	1,800 MHz
Type	electromagnetic field
Charakteristic	near field
Exposure duration	90 min/day every day or every second day for up to 83 days (detailed description in "aim of study")

Exposure setup

Exposure source	cellular phone in speaking mode
Chamber	4 mice per cage
Setup	mobile phone was placed under each cage; cages were placed within specially constructed rectangular one-side opened Faraday cages
Sham exposure	A sham exposure was conducted.
Additional info	cages containing the sham exposed mice located at the other side of the room within rectangular complete Faraday cages; during exposure and sham exposure auditory stimulation (70 db) was generated by a playing radio station (to simulate human voice during mobile phone operation)

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	0.11 W/kg	effective value	calculated	-	-
electric field strength	12 V/m	average over time	measured	-	within the cages

Additional parameter details

average values of ELF components of the time domain multiple access (TDMA) GSM signal consisting of 217 Hz and its harmonics: 40 - 70 nT (in the fundamental frequency and up to the fourth-order harmonics); background radiofrequency signals below 0.15 V/m integrated over 6 min (ranged from FM stations, TV and mast antennas); background ELF fields throughout the animal facility from 80 to 120 nT at the frequency band of 4-32.000 Hz with a predominant frequency of 50 Hz and its harmonics deriving from power lines

Reference articles

Ntzouni MP et al. (2011): Short-term memory in mice is affected by mobile phone radiation
Peyman A et al. (2007): Dielectric properties of porcine cerebrospinal tissues at microwave frequencies: in vivo, in vitro and systematic variation with age
Nightingale NR et al. (1983): The dielectric properties of the cerebellum, cerebrum and brain stem of mouse brain at radiowave and microwave frequencies

Exposed system:

animal
mouse/C57BL/6J
whole body

Methods Endpoint/measurement parameters/methodology

cognitive/behavioral endpoints: spatial (object location test) and non-spatial (object recognition test) memory performance (exploration behavior)

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)

In the first experiment, the exposed animals showed a significant reduced memory performance in the second (1b) and the third testing (1c) in the spatial and the non-spatial test when compared to the control group. No significant differences were found between the control group and the sham exposed group or in the testing 1a. In the second experiment, the exposed mice showed significant memory impairments when tested during the first exposure period and when tested the first time after the first exposure period in the spatial and in the non-spatial test (testing 2b and 2c). No significant differences were found between the control group and the sham exposed group or in the testings 2a, 2d and 2e.
The authors conclude that exposure to radiofrequency electromagnetic fields could induce spatial and non-spatial transient memory impairments in mice.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

European Union (EU)/European Commission
THALES Programme
University of Athens, Greece

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