Study type: Medical/biological study (experimental study)

Electromagnetic fields from mobile phones do not affect the inner auditory system of Sprague-Dawley rats med./bio.

By: Galloni P, Parazzini M, Piscitelli M, Pinto R, Lovisolo GA, Tognola G, Marino C, Ravazzani P
Published in: Radiat Res 2005; 164 (6): 798-804
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Aim of study (acc. to author)

To evaluate the cochlear functionality of rats exposed to electromagnetic fields at the typical frequencies of GSM mobile phones (900 and 1800 MHz) by distortion product otoacoustic emissions.

Background/further details

The study is part of the GUARD project ("Potential Adverse Effects of GSM Cellular Phones on Hearing"), funded by the European Commission.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 900 MHz
Modulation type: pulsed
Exposure duration: repeated daily exposure, 2 h/day, 5 days/week for 4 weeks
Exposure 2: 1,800 MHz
Modulation type: pulsed
Exposure duration: repeated daily exposure, 2 h/day, 5 days/week for 4 weeks

Exposure 1

Main characteristics
Frequency 900 MHz
Type
Charakteristic
Exposure duration repeated daily exposure, 2 h/day, 5 days/week for 4 weeks
Modulation
Modulation type pulsed
Additional info

GSM modulation
Exposure setup
Exposure source
Distance between exposed object and exposure source 10 mm
Chamber The exposure system for 12 rats consisted of three distinct arrays of four loop antennas printed on dielectric substrate, two for real and one for sham exposure (blinded). It was assembled in a wooden rack with RF-absorbing panels inserted between the arrays and on the four sides of the rack. Rats were placed close to a different antenna (in the same array) each day to obtain a uniform distribution of exposure.
Setup Animals were held in individual Perspex jigs with cylindrical tubes with a cone-shaped head end and a lockable piston in the tail end. Each antenna was held perpendicular to the head surface over the right ear of each rat in contact with the external side of the Perspex jig with a total distance from the cochlear system of about 8-10 mm.
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
SAR 2 W/kg cf. remarks measured and calculated - local SAR in the cochlea
Additional parameter details

Fields at 50 Hz in the set-up were B = 0.05-0.08 µT and E = 0.7-1.7 V/m.

Measurement and calculation details

Numerical dosimetry was performed using a commercial FDTD code on a realistic model of the rat head with five fundamental tissues and a loop antenna positioned at 5 mm from the head surface. Measurements were performed using miniature probes on homogeneous phantoms and in the inner ear of a rat's cadaver using the power pulse method and a fluoroptic thermometer. Numerical and experimental dosimetry showed a good agreement.

Exposure 2

Main characteristics
Frequency 1,800 MHz
Type
Charakteristic
Exposure duration repeated daily exposure, 2 h/day, 5 days/week for 4 weeks
Modulation
Modulation type pulsed
Additional info

GSM modulation
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
SAR 2 W/kg cf. remarks measured and calculated - local SAR in the cochlea

Reference articles

  • Chou CK et al. (1999): Development of a rat head exposure system for simulating human exposure to RF fields from handheld wireless telephones

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 data showed no statistically significant differences between the audiological signals recorded for the different exposed and sham-exposed groups. There were no statistically significant changes in the outer hair cell functionality of rats exposed to electromagnetic fields at both GSM frequencies compared to the sham-exposed group.

Study character:

Study funded by

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