Medical/biological study (experimental study)

Absence of daytime 50 Hz, 100 microT(rms) magnetic field or bright light exposure effect on human performance and psychophysiological parameters med./bio.

By: Crasson M, Legros JJ

Published in: Bioelectromagnetics 2005; 26 (3): 225-233

Aim of study (acc. to author)

To reproduce and extend two earlier studies of the effects of human exposure to 50 Hz magnetic fields (publication 3569).

Background/further details

In the recent paper, the results of two double-blind investigations performed to examine effects of 100 µT 50 Hz magnetic field exposure on psychological parameters in the same group of healthy human volunteers were described.
In the present study, another group of 18 healthy subjects were exposed to three experimental sessions of 30 min each, given at 1 week intervals (the sessions consisted of continuous 100 µT 50 Hz magnetic field exposure, sham exposure, and bright light (5000 lux) exposure which was intended to be a positive control).

Endpoint

effects on the neurological system: event-related potentials/psychophysiological parameters
hypersensitivity/subjective complaints: psychological parameters/mood ratings

Exposure

- 50/60 Hz
- magnetic field

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: continuous for 30 min	magnetic flux density: 100 µT effective value

General information

Subjects were exposed to 3 experimental sessions consisting of 50 Hz magnetic field exposure, sham exposure and bright light (5000 lux) exposure.

Exposure 1

Main characteristics

Frequency	50 Hz
Type	magnetic field
Waveform	sinusoidal
Exposure duration	continuous for 30 min

Exposure setup

Exposure source	Helmholtz coils
Setup	Subjects were seated in the exposure facility with their heads placed in the magnetic helmet which produced a magnetic field that was directed from right mandibula to left parietal site of the head.
Additional info	The helmet was formed by six Helmholtz coils distributed in three orthogonal directions. During the exposure one vertical and one horizontal pair of coils was energized.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	100 µT	effective value	measured	-	-

Additional parameter details

The ambient sinusoidal magnetic field and geomagnetic field was measured to be 0.06 µT and 40 µT, respectively.

Reference articles

Crasson M et al. (1999): 50 Hz magnetic field exposure influence on human performance and psychophysiological parameters: two double-blind experimental studies

Exposed system:

human
partial body: head

Methods Endpoint/measurement parameters/methodology

effects on the neurological system: event-related potentials (attentional processes (auditory selective attention task (dichotic listening task), visual discrimination task (oddball paradigm)); EEG
cognitive/behavioral endpoints: attention tests (duration discrimination task; visual, selective attention task)
hypersensitivity/subjective complaints: psychological parameters/mood ratings (visual analogue scale; state scale of the State-Trait Anxiety Inventory; Field Status Questionnaire)
EOG

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)

The results on mood, event-related potentials, reaction time, and other performance measures did not show any differences among the sham exposure, light exposure, and magnetic field exposure conditions.
The data of this study do not support the hypothesis that extremely low frequency magnetic field exposure affects the brain's electrical activity or cognitive function at field strength similar to that found in very close proximity of some household and industrial electrical appliances and well in excess of the average magnetic field strength found in homes.
The sensitivity of the experiment was possibly not sufficient to detect an effect at this relatively low magnetic field. Larger sample sizes would be required in further studies.

Study character:

medical/biological study
experimental study
full/main study
double-blind study

Study funded by

Elia, Belgium

Replicated studies

Crasson M et al. (1999): 50 Hz magnetic field exposure influence on human performance and psychophysiological parameters: two double-blind experimental studies

Balassa T et al. (2009): Effect of short-term 50 Hz electromagnetic field exposure on the behavior of rats
Liu T et al. (2008): Anxiogenic effect of chronic exposure to extremely low frequency magnetic field in adult rats
Nevelsteen S et al. (2007): Effects of information and 50 Hz magnetic fields on cognitive performance and reported symptoms
Legros A et al. (2006): Individual subject sensitivity to extremely low frequency magnetic field
Marino AA et al. (2004): Effect of low-frequency magnetic fields on brain electrical activity in human subjects
Podd J et al. (2002): Brief exposure to a 50 Hz, 100 µT magnetic field: effects on reaction time, accuracy, and recognition memory
Crasson M et al. (1999): 50 Hz magnetic field exposure influence on human performance and psychophysiological parameters: two double-blind experimental studies
Trimmel M et al. (1998): Effects of an ELF (50 Hz, 1 mT) electromagnetic field (EMF) on concentration in visual attention, perception and memory including effects of EMF sensitivity