Medical/biological study (experimental study)

Changes in human EEG alpha activity following exposure to two different pulsed magnetic field sequences med./bio.

By: Cook CM, Saucier DM, Thomas AW, Prato FS

Published in: Bioelectromagnetics 2009; 30 (1): 9-20

Aim of study (acc. to author)

To examine the effects of pulsed extremely low frequency magnetic field sequences upon alpha wave activity (8-13 Hz) of the human EEG over the occipital-parietal regions.

Background/further details

Two previous studies (see publication 11906 and publication 10628) determined that exposure to pulsed extremely low frequency electromagnetic fields can affect the EEG, notably the alpha wave frequency (8-13 Hz). In the present study 22 participants from two previous studies (see publication 11906 [sequence 2 with a refractory period of 5000 ms] and publication 10628 [sequence 1 with a refractory period of 1200 ms]) and 10 additional subjects were randomly assigned to two different pulsed magnetic field sequences, used in the previous studies. Participation consisted of two sessions (exposure and sham exposure), separated by approximately 1 week (7+/-2 days).

Endpoint

effects on the neurological system: EEG

Exposure

- magnetic field
- signals/pulses

Exposure	Parameters
Exposure 1: 0–500 Hz Modulation type: pulsed Exposure duration: continuous for 15 min	magnetic flux density: 200 µT peak value

General information

two different pulse forms were used a) pulses with a refractory period of 1200 ms b) pulses with a refractory period of 5000 ms

Exposure 1

Main characteristics

Frequency	0–500 Hz
Type	magnetic field
Exposure duration	continuous for 15 min

Modulation

Modulation type	pulsed
Pulse width	853 ms
Rise time	1 ms

Exposure setup

Exposure source	Helmholtz coils
Setup	three orthogonal square Helmholtz coils with 2.0 m, 1.75 m, 1.5 m sides and 10 turns of 8-gauge stranded conductor each
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	200 µT	peak value	measured	-	-

Reference articles

Cook CM et al. (2005): Resting EEG effects during exposure to a pulsed ELF magnetic field
Cook CM et al. (2004): Resting EEG is affected by exposure to a pulsed ELF magnetic field
Thomas AW et al. (2001): Human subjects exposed to a specific pulsed (200 microT) magnetic field: effects on normal standing balance
Thomas AW et al. (2001): A comparison of rheumatoid arthritis and fibromyalgia patients and healthy controls exposed to a pulsed (200 microT) magnetic field: effects on normal standing balance
Thomas AW et al. (2001): Magnetic field exposure and behavioral monitoring system
Thomas AW et al. (1998): Analgesic effects of a specific pulsed magnetic field in the land snail, Cepaea nemoralis: consequences of repeated exposures, relations to tolerance and cross-tolerance with DPDPE
Thomas AW et al. (1997): Antinociceptive effects of a pulsed magnetic field in the land snail, Cepaea nemoralis
Thomas AW et al. (1997): Pulsed magnetic field induced "analgesia" in the land snail, Cepaea nemoralis, and the effects of mu, delta, and kappa opioid receptor agonists/antagonists

Exposed system:

human
whole body

Methods Endpoint/measurement parameters/methodology

effects on the neurological system: EEG (alpha wave frequency, 8-13 Hz)

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)

Compared to sham exposure, alpha wave activity was lowered over the occipital-parietal regions of the brain during exposure to sequence 1, while alpha wave activity over the same regions was higher after sequence 2 exposure. The effects occured after 5 min of exposure and were dependent on the order of exposure (magnetic field followed by sham exposure).
This study supports previous observations of EEG changes after 5 min pulsed extremely low frequency magnetic field exposure. The results also suggest that a previous exposure to the pulsed magnetic field sequence determined subjects´ responses in the present experiment, i.e. subjects previously exposed to sequence 1(and now to sequence 2) displayed higher occipital alpha wave activity after magnetic field exposure. Subjects previously exposed to sequence 2 (and now sequence 1) displayed lower alpha wave activity over posterior scalp regions in the present study.

Study character:

medical/biological study
experimental study
replication/reproduction study
single blind study

Study funded by

Canadian Foundation for Innovation (CFI), Canada
Canadian Institutes of Health Research (CIHR)
Lawson Health Research Institute, Canada
Ontario Innovation Trust (OIT), Canada
Ontario Research and Development Challenge Fund (ORDCF), Canada
Plunkett Foundation, UK

Replicated studies

Cook CM et al. (2005): Resting EEG effects during exposure to a pulsed ELF magnetic field
Cook CM et al. (2004): Resting EEG is affected by exposure to a pulsed ELF magnetic field

Modolo J et al. (2017): Human exposure to power frequency magnetic fields up to 7.6 mT: An integrated EEG/fMRI study
Loughran SP et al. (2013): No increased sensitivity in brain activity of adolescents exposed to mobile phone-like emissions
Perentos N et al. (2013): The alpha band of the resting electroencephalogram under pulsed and continuous radio frequency exposures
Legros A et al. (2012): Neurophysiological and behavioral effects of a 60 Hz, 1,800 µT magnetic field in humans
Vecchio F et al. (2010): Mobile phone emission modulates inter-hemispheric functional coupling of EEG alpha rhythms in elderly compared to young subjects
Croft RJ et al. (2010): Effects of 2G and 3G mobile phones on human alpha rhythms: Resting EEG in adolescents, young adults, and the elderly
Cvetkovic D et al. (2009): Alterations of human electroencephalographic activity caused by multiple extremely low frequency magnetic field exposures
Croft RJ et al. (2008): The effect of mobile phone electromagnetic fields on the alpha rhythm of human electroencephalogram
Perentos N et al. (2008): The effect of GSM-like ELF radiation on the alpha band of the human resting EEG
Vecchio F et al. (2007): Mobile phone emission modulates interhemispheric functional coupling of EEG alpha rhythms
Regel SJ et al. (2007): Pulsed radio frequency radiation affects cognitive performance and the waking electroencephalogram
Carrubba S et al. (2007): Nonlinear EEG activation evoked by low-strength low-frequency magnetic fields
Regel SJ et al. (2007): Pulsed radio-frequency electromagnetic fields: dose-dependent effects on sleep, the sleep EEG and cognitive performance
Cvetkovic D et al. (2006): Alterations in Human EEG Activity Caused by Extremely Low Frequency Electromagnetic Fields
Cook CM et al. (2006): Exposure to ELF magnetic and ELF-modulated radiofrequency fields: the time course of physiological and cognitive effects observed in recent studies (2001-2005)
Cook CM et al. (2005): Resting EEG effects during exposure to a pulsed ELF magnetic field
Cook CM et al. (2004): Resting EEG is affected by exposure to a pulsed ELF magnetic field