Study type: Medical/biological study (experimental study)

Are some people sensitive to mobile phone signals? Within participants double blind randomised provocation study. med./bio.

Published in: BMJ 2006; 332 (7546): 886-891

Aim of study (acc. to author)

To study whether people who report being sensitive to mobile phone signals have more symptoms when exposed to a pulsing mobile phone signal than when exposed to a sham signal or a non-pulsing signal.

Background/further details

60 "sensitive" subjects participated who reported often getting headache-like symptoms within 20 minutes of using a GSM mobile phone and 60 "control" participants who did not report any such symptoms. Participants completed visual analogue scale measures after 5, 15, 30, and 50 minutes of exposure and 30 min after the end of each exposure.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 900 MHz
Modulation type: pulsed
Exposure duration: continuous for 50 min
  • SAR: 1.4 W/kg unspecified (±30%)
Exposure 2: 900 MHz
Modulation type: CW
Exposure duration: continuous for 50 min
  • SAR: 1.4 W/kg unspecified (±30%)

Exposure 1

Main characteristics
Frequency 900 MHz
Type
Exposure duration continuous for 50 min
Modulation
Modulation type pulsed
Additional info

GSM

Exposure setup
Exposure source
Chamber Both testing rooms, which were lit by two table lamps, were not shielded against outside EMF.
Setup A headband mounted standard GSM handset system was used for exposures with the antenna positioned slightly above and behind the left ear and within a few millimetres of the participant's scalp.
Sham exposure A sham exposure was conducted.
Additional info For sham exposure, a CW signal was generated to ensure that the system heated up to the same degree as during the active exposures but was diverted to an internal load instead of being transmitted through the antenna; only minimal leakage of this signal occurred.
Parameters
Measurand Value Type Method Mass Remarks
SAR 1.4 W/kg unspecified calibration - ±30%

Exposure 2

Main characteristics
Frequency 900 MHz
Type
Exposure duration continuous for 50 min
Modulation
Modulation type CW
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
SAR 1.4 W/kg unspecified calibration - ±30%

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

The data did not indicate that people with self reported sensitivity to mobile phone signals are able to detect such signals or that they react to them with increased symptom severity. As sham exposure was sufficient to trigger severe symptoms in some subjects, psychological factors may have an important role in causing this condition.

Study character:

Study funded by

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