Effects of personalised exposure on self-rated electromagnetic hypersensitivity and sensibility - A double-blind randomised controlled trial. med./bio.

Published in: Environ Int 2017; 99: 255-262

Aim of study (acc. to author)

The self-reported sensing ability of radio-frequency or extremely low-frequency fields should be investigated in an experimental study design in the personal environment of subjects.

Background/further details

42 adults (76% women) participated in the study. Subjects were eligible if they reported to sense one of the available experimental EMF signals (GSM 900, GSM 1800, DECT, UMTS and WiFi) or extremely low-frequency magnetic fields (50 Hz sine signal or four different types of signals with other frequency components added, so called dirty electricity) within minutes of being exposed, or developing acute and transient health complaints. Each participant was sent a questionnaire after inclusion in the study. Then they were visited at home or another location where they felt comfortable, filled in a further questionnaire and an un-blinded exposure session was applied to determine the type of signal, signal strength and exposure duration that participants reported sensing or reacting to. This was followed by a double-blind trial of 10-20 exposure or sham exposure conditions in randomized sequence. Directly after each condition, participants specified on a form whether they thought exposure had been applied or not. After testing, participants again filled in a questionnaire and then the test results were communicated to the participants, i.e. the percentage of correct field on/off answers. 2 and 4 months after participation, they were sent a follow-up questionnaire.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 925–960 MHz
Exposure duration: maximum of 15 min per condiiton (individually defined during pretests)
Exposure 2: 1,805–1,880 MHz
Exposure duration: maximum of 15 min per condiiton (individually defined during pretests)
  • see parameters and details in exposure 1
Exposure 3: 1,880–1,900 MHz
Exposure duration: maximum of 15 min per condiiton (individually defined during pretests)
  • see parameters and details in exposure 1
Exposure 4: 2,110–2,170 MHz
Exposure duration: maximum of 15 min per condiiton (individually defined during pretests)
  • see parameters and details in exposure 1
Exposure 5: 2,400–2,500 MHz
Exposure duration: maximum of 15 min per condiiton (individually defined during pretests)
  • see parameters and details in exposure 1
Exposure 6: 50 Hz
Exposure duration: maximum of 15 min per condiiton (individually defined during pretests)
Exposure 7: 50 Hz
Exposure duration: maximum of 15 min per condiiton (individually defined during pretests)
LED
  • see parameters and details in exposure 6

Exposure 1

Main characteristics
Frequency 925–960 MHz
Type
Exposure duration maximum of 15 min per condiiton (individually defined during pretests)
Additional info GSM 900
Exposure setup
Exposure source
Chamber at home or another placewhere the person felt comfortable
Setup 14% of participants chose GSM 900 or GSM 1800 signal
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 0.2 V/m mean - partial body minimum average value for upper body
electric field strength 6 V/m mean - partial body maximum average value for upper body
electric field strength 0.44 V/m mean - partial body median of average value for upper body

Exposure 2

Main characteristics
Frequency 1,805–1,880 MHz
Type
Exposure duration maximum of 15 min per condiiton (individually defined during pretests)
Additional info GSM 1800
Exposure setup
Exposure source
Setup 14% of participants chose GSM900 or GSM1800 signal
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
cf. remarks - - - - see parameters and details in exposure 1

Exposure 3

Main characteristics
Frequency 1,880–1,900 MHz
Type
Exposure duration maximum of 15 min per condiiton (individually defined during pretests)
Additional info DECT
Exposure setup
Exposure source
Setup 8% of participants chose DECT signal
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
cf. remarks - - - - see parameters and details in exposure 1

Exposure 4

Main characteristics
Frequency 2,110–2,170 MHz
Type
Exposure duration maximum of 15 min per condiiton (individually defined during pretests)
Additional info UMTS
Exposure setup
Exposure source
Setup 41% of participants chose UMTS signal
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
cf. remarks - - - - see parameters and details in exposure 1

Exposure 5

Main characteristics
Frequency 2,400–2,500 MHz
Type
Exposure duration maximum of 15 min per condiiton (individually defined during pretests)
Additional info WiFi
Exposure setup
Exposure source
Setup 38% of participants chose WiFi signal
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
cf. remarks - - - - see parameters and details in exposure 1

Exposure 6

Main characteristics
Frequency 50 Hz
Type
Exposure duration maximum of 15 min per condiiton (individually defined during pretests)
Additional info power line
Exposure setup
Exposure source
Setup 2 participants chose power line signal
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.15 µT minimum - - two persons were exposed to this value
magnetic flux density 6.6 µT maximum - - two persons were exposed to this value

Exposure 7

Main characteristics
Frequency 50 Hz
Type
Exposure duration maximum of 15 min per condiiton (individually defined during pretests)
Additional info LED
Exposure setup
Exposure source
Setup 2 participants chose LED signal
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
cf. remarks - - - - see parameters and details in exposure 6

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

None of the participants was able to correctly identify when they were being exposed better than chance. There were no significant differences in the self-reported level of electromagnetic hypersensitivity after 2 and 4 months compared to before the test but after 2 and 4 months, participants reported significantly reduced certainty in reacting within minutes to exposure, significantly fewer symptoms compared to before the test and significantly reduced severity of symptoms.
The authors conclude that there was no indication for a sensing ability of radio-frequency or extremely low-frequency fields in subjects. However, the results indicate that a subgroup of persons with electromagnetic hypersensitivity might profit from participation in such a personalised testing procedure regarding their symptoms.

Study character:

Study funded by

Related articles