Study type: Medical/biological study (experimental study)

Investigation of potential effects of cellular phones on human auditory function by means of distortion product otoacoustic emissions. med./bio.

Published in: J Acoust Soc Am 2005; 117 (3) Pt 1: 1241-1247

Aim of study (acc. to author)

To study potential effects of electromagnetic fields of GSM cellular phones on outer hair cells (cochlea) by means of distortion product otoacoustic emissions.

Background/further details

Distortion product otoacoustic emissions (DPOAEs) were measured within transmission pauses, i.e. between electromagnetic field signal pulses. Thus, an undistorted measurement of DPOAEs was possible during exposure.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 900 MHz
Modulation type: pulsed
Exposure duration: intermittent, 3 min on/off=sham, for 24 min

Exposure 1

Main characteristics
Frequency 900 MHz
Type
Exposure duration intermittent, 3 min on/off=sham, for 24 min
Modulation
Modulation type pulsed
Pulse width 0.5763 ms
Additional info

Transmission pause between consecutive pulses of the GSM-like signal was increased from 4.034 ms to 24.204 ms.

Exposure setup
Exposure source
Distance between exposed object and exposure source 5 cm
Exposure room Sound-proof, electromagnetically shielded room (6.5 x 2.8 x 3.0 m) with walls, floor, and ceiling covered by RF-absorbing materials. Nothing but the mobile phone dummy and the subject lying quietly on a plastic camp bed were in the room.
Additional info For each subject, each DPOA measurement was repeated 8 times, applying EMF and sham exposure in alternating order (single-blind). In total, each subject underwent 12 tests each test lasting about 24 min. Testing was broken up into multiple sessions. The measuring procedure was the same for sham as for EMF exposure but the EMF was switched off.
Parameters
Measurand Value Type Method Mass Remarks
power 0.465 W mean - - -
SAR 0.1 W/kg mean - - -
SA 2.42 mWs/kg mean - - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

No significant change in the DPOAE level in response to the electromagnetic field exposure was revealed. However, when undesired side effects on DPOAEs were compensated, in some subjects an extremely small electromagnetic field-exposure-correlated change in the DPOAE level (< 1 dB) was found. In view of the very large dynamic range of hearing in humans (120 dB), it is suggested that this observation is physiologically irrelevant.

Study character:

Study funded by

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