Medical/biological study (experimental study)

Sleep EEG alterations: effects of pulsed magnetic fields versus pulse-modulated radio frequency electromagnetic fields med./bio.

By: Schmid MR, Murbach M, Lustenberger C, Maire M, Kuster N, Achermann P, Loughran SP

Published in: J Sleep Res 2012; 21 (6): 620-629

Aim of study (acc. to author)

The aim of the study was to test if a signal without significant harmonics above 20 Hz is sufficient to influence the EEG. In addition (part 2), the authors wanted to investigate whether applying a magnetic field with the same pulse sequence as applied in the pulse modulated radiofrequency exposure would result in similar changes in the EEG.

Background/further details

Part 2 was an attempt to test the demodulation hypothesis, i.e. that the effects are induced by the demodulated radiofrequency signal (corresponding to the low frequency envelope of the transmitted signal) via an electrically non-linear structure inside the human brain. Demodulation occurring in the brain has been proposed as one possible mechanism for the effects of pulse modulated radiofrequency electromagnetic fields.
25 young healthy men were exposed/sham exposed at weekly intervals to three different conditions for 30 min before sleep.

Endpoint

cognitive/behavioral endpoints: cognitive tasks
sleep: polysomnography (EEG, EMG, ECG)

Exposure

- magnetic field
- low frequency
- RF field
- signals/pulses
- PW pulsed wave

Exposure	Parameters
Exposure 1: 900 MHz Modulation type: pulsed Exposure duration: continuous for 30 min	SAR: 2 W/kg (peak spatial average of head tissue)
Exposure 2: 2 Hz Exposure duration: continuous for 30 min	magnetic flux density: 0.176 mT cf. remarks (whole-brain time and spatial average) magnetic flux density: 0.7 mT peak value

Exposure 1

Main characteristics

Frequency	900 MHz
Type	electromagnetic field
Exposure duration	continuous for 30 min

Modulation

Modulation type	pulsed
Repetition frequency	2.08 Hz
Additional info	Pulsed signals had a basic modulation frequency of 2 Hz and a peak-to-average ratio of 4 in pulse amplitude. In order to reduce the higher harmonics the pulse structures were smoothened by applying a Gaussian low-pass filter (-3 dB at 20 Hz), reducing the spectral power above 20 Hz by more than a factor of 10 and by approx. 10 000 at 50 Hz.

Exposure setup

Exposure source	patch antennas
Distance between measurement device and exposed object	115 mm
Setup	patch antenna 42 mm vertically above ear canal, 115 mm from left side of head (unilateral exposure)
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	2 W/kg	-	-	-	peak spatial average of head tissue

Additional parameter details

input power adjusted to optain SAR value of 2 W/kg

Exposure 2

Main characteristics

Frequency	2 Hz
Type	magnetic field
Waveform	pulsed
Exposure duration	continuous for 30 min

Exposure setup

Exposure source	Helmholtz coils
Setup	rectangular shaped coils (33 x 39 cm, 2 x 23 windings) on each side of the head separated by 25.7 ± 0.5 cm, depending on the participant's anatomy
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	0.176 mT	cf. remarks	calculated	-	whole-brain time and spatial average
magnetic flux density	0.7 mT	peak value	-	-	-

Reference articles

Schmid MR et al. (2012): Sleep EEG alterations: effects of different pulse-modulated radio frequency electromagnetic fields
Boutry CM et al. (2008): Dosimetric evaluation and comparison of different RF exposure apparatuses used in human volunteer studies
Huber R et al. (2003): Radio frequency electromagnetic field exposure in humans: Estimation of SAR distribution in the brain, effects on sleep and heart rate
Huber R et al. (2002): Electromagnetic fields, such as those from mobile phones, alter regional cerebral blood flow and sleep and waking EEG

Exposed system:

human
partial body: head (for RF exposure left side only)

Methods Endpoint/measurement parameters/methodology

cognitive/behavioral endpoints: cognitive tasks during exposure (simple reaction time task, choice reaction time task, n-back task)
hypersensitivity/subjective complaints: field perception, well-being, mood (questionnaire)
sleep: polysomnography (EEG, EMG, ECG): sleep stages, Non-REM sleep, REM sleep (mean power spectral density); total sleep time, sleep latency, REM sleep latency, sleep efficiency, waking after sleep onset, slow wave sleep

Investigated system:

investigation on living organism

Investigated organ system:

brain/CNS

Time of investigation:

during exposure
after exposure

Main outcome of study (acc. to author)

Radiofrequency exposure increased EEG power in the spindle frequency range. Furthermore, delta wave and theta wave activity (Non-REM sleep), and alpha wave and delta wave activity (REM sleep) were affected following both exposure conditions. No effect on sleep architecture and no clear impact of exposure on cognition was observed.
These findings demonstrated that both pulse modulated radiofrequency and pulsed magnetic fields affected brain physiology, and the presence of significant frequency components above 20 Hz was not fundamental for these effects to occur. Because responses were not identical for all exposures, the study does not support the hypothesis that effects of radiofrequency exposure are based on demodulation of the signal only.

Study character:

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

Study funded by

Nationales Forschungsprogramm NFP 57 (National Research Programme NRP 57), Switzerland
Swiss National Science Foundation (SNF)

Danker-Hopfe H et al. (2016): Effects of mobile phone exposure (GSM 900 and WCDMA/UMTS) on polysomnography based sleep quality: An intra- and inter-individual perspective
Lustenberger C et al. (2015): Inter-individual and intra-individual variation of the effects of pulsed RF EMF exposure on the human sleep EEG
Lustenberger C et al. (2013): Stimulation of the brain with radiofrequency electromagnetic field pulses affects sleep-dependent performance improvement
Vecchio F et al. (2012): Mobile phone emission increases inter-hemispheric functional coupling of electroencephalographic alpha rhythms in epileptic patients
Vecchio F et al. (2012): Mobile phone emission modulates event-related desynchronization of alpha rhythms and cognitive-motor performance in healthy humans
Barth A et al. (2012): No effects of short-term exposure to mobile phone electromagnetic fields on human cognitive performance: A meta-analysis
Loughran SP et al. (2012): Individual differences in the effects of mobile phone exposure on human sleep: Rethinking the problem
Schmid MR et al. (2012): Sleep EEG alterations: effects of different pulse-modulated radio frequency electromagnetic fields
Danker-Hopfe H et al. (2011): Effects of electromagnetic fields emitted by mobile phones (GSM 900 and WCDMA/UMTS) on the macrostructure of sleep
Regel SJ et al. (2011): Cognitive performance measures in bioelectromagnetic research - critical evaluation and recommendations
Lowden A et al. (2011): Sleep after mobile phone exposure in subjects with mobile phone-related symptoms
Valentini E et al. (2010): Systematic review and meta-analysis of psychomotor effects of mobile phone electromagnetic fields
Danker-Hopfe H et al. (2010): Do mobile phone base stations affect sleep of residents? Results from an experimental double-blind sham-controlled field study
Kowalczuk C et al. (2010): Absence of nonlinear responses in cells and tissues exposed to RF energy at mobile phone frequencies using a doubly resonant cavity
Cvetkovic D et al. (2009): Alterations of human electroencephalographic activity caused by multiple extremely low frequency magnetic field exposures
Arnetz BB et al. (2007): The Effects of 884 MHz GSM Wireless Communication Signals on Self-reported Symptom and Sleep (EEG)- An Experimental Provocation Study
Regel SJ et al. (2007): Pulsed radio-frequency electromagnetic fields: dose-dependent effects on sleep, the sleep EEG and cognitive performance
Valentini E et al. (2007): Neurophysiological effects of mobile phone electromagnetic fields on humans: a comprehensive review
Fritzer G et al. (2007): Effects of short- and long-term pulsed radiofrequency electromagnetic fields on night sleep and cognitive functions in healthy subjects
Arnetz B et al. (2007): The Effects of 884 MHz GSM Wireless Communication Signals on Self-reported Symptom and Sleep (EEG)- An Experimental Provocation Study
Loughran SP et al. (2005): The effect of electromagnetic fields emitted by mobile phones on human sleep
Huber R et al. (2002): Electromagnetic fields, such as those from mobile phones, alter regional cerebral blood flow and sleep and waking EEG
Wagner P et al. (2000): Human sleep EEG under the influence of pulsed radio frequency electromagnetic fields. Results from polysomnographies using submaximal high power flux densities
Huber R et al. (2000): Exposure to pulsed high-frequency electromagnetic field during waking affects human sleep EEG
Borbely AA et al. (1999): Pulsed high-frequency electromagnetic field affects human sleep and sleep electroencephalogram
Wagner P et al. (1998): Human sleep under the influence of pulsed radiofrequency electromagnetic fields: a polysomnographic study using standardized conditions
Mann K et al. (1996): [REM suppression induced by digital mobile radio telephones]
Mann K et al. (1996): Effects of pulsed high-frequency electromagnetic fields on human sleep

Sleep EEG alterations: effects of pulsed magnetic fields versus pulse-modulated radio frequency electromagnetic fields med./bio.

Aim of study (acc. to author)

Background/further details

Endpoint

Exposure

Exposure 1

Main characteristics

Modulation

Exposure setup

Parameters

Additional parameter details

Exposure 2

Main characteristics

Exposure setup

Parameters

Reference articles

Methods Endpoint/measurement parameters/methodology

Main outcome of study (acc. to author)

Study funded by

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