Medical/biological study (experimental study)

Do GSM 900 MHz signals affect cerebral blood circulation? A near-infrared spectrophotometry study. med./bio.

By: Wolf M, Haensse D, Morren G, Fröhlich J

Published in: Opt Express 2006; 14 (13): 6128-6142

Aim of study (acc. to author)

To study the effects of GSM 900 MHz signals on the cerebral blood circulation using near-infrared spectrophotometry (NIRS) in 16 healthy volunteers.

Background/further details

NIRS has been well established as a tool to study activity of the brain and e.g. applied to record changes in oxy-hemoglobin and deoxy-hemoglobin concentrations in the visual and motor cortices during functional stimulation. Oxy-hemoglobin and deoxy-hemoglobin are related to cerebral blood flow and cerebral blood volume.
Compared to previous studies using positron emission tomography, NIRS provides a much higher time resolution, which allows investigating the short term effects efficiently, non-invasively, without the use of radioactive tracers and with high sensitivity.

Endpoint

effects on the neurological system: cerebral blood flow

Exposure

- mobile communications
- mobile phone
- GSM

Exposure	Parameters
Exposure 1: 900 MHz Modulation type: pulsed Exposure duration: 15 cycles: 20 s exposure (intermittend 2 s on/2 s off) and 60 s rest (total of 24 min.)	SAR: 1.2 W/kg spatial average (10 g) SAR: 12 W/kg spatial average (10 g)

Exposure 1

Main characteristics

Frequency	900 MHz
Type	electromagnetic field
Exposure duration	15 cycles: 20 s exposure (intermittend 2 s on/2 s off) and 60 s rest (total of 24 min.)

Modulation

Modulation type	pulsed
Repetition frequency	217 Hz

Exposure setup

Exposure source	signal generator
Setup	The antenna was positioned on a location close to the left ear.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	1.2 W/kg	spatial average	calculated	10 g	-
SAR	12 W/kg	spatial average	calculated	10 g	-

Reference articles

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.

Exposed system:

human
partial body: head (left ear)

Methods Endpoint/measurement parameters/methodology

effects on the neurological system: cerebral blood flow, cerebral blood volume (concentrations of oxyhemoglobin and deoxyhemoglobin (near-infrared spectrophotometry))

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)

During exposure (within 20 s) borderline significant short term responses of oxy-hemoglobin and deoxy-hemoglobin concentrations were observed, which correspond to a decrease of cerebral blood flow and cerebral blood volume and were much smaller than regular physiological changes elicited e.g. by functional activation of the brain.
There was no detectable dose-response relation or long term response within 20 minutes.

Study character:

medical/biological study
experimental study
full/main study
double-blind study, cross-over study

Study funded by

Federal Office of Public Health (FOPH; Bundesamt für Gesundheit), Switzerland
Forschungsstiftung Mobilkommunikation (FSM; Research Foundation on Mobile Communication; at the Swiss Federal Institute of Technology Zurich (ETH)), Switzerland

Lv B et al. (2014): The alteration of spontaneous low frequency oscillations caused by acute electromagnetic fields exposure.
Curcio G et al. (2012): Effects of mobile phone signals over BOLD response while performing a cognitive task.
Spichtig S et al. (2012): Assessment of intermittent UMTS electromagnetic field effects on blood circulation in the human auditory region using a near-infrared system.
Kwon MS et al. (2012): No effects of short-term GSM mobile phone radiation on cerebral blood flow measured using positron emission tomography.
Spichtig S et al. (2012): Assessment of potential short-term effects of intermittent UMTS electromagnetic fields on blood circulation in an exploratory study, using near-infrared imaging.
Kwon MS et al. (2011): GSM mobile phone radiation suppresses brain glucose metabolism.
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Volkow ND et al. (2011): Effects of cell phone radiofrequency signal exposure on brain glucose metabolism.
Masuda H et al. (2011): Local exposure of the rat cortex to radiofrequency electromagnetic fields increases local cerebral blood flow along with temperature.
Mizuno Y et al. (2009): Effects of W-CDMA 1950 MHz EMF emitted by mobile phones on regional cerebral blood flow in humans.
Curcio G et al. (2009): Acute mobile phones exposure affects frontal cortex hemodynamics as evidenced by functional near-infrared spectroscopy.
Aalto S et al. (2006): Mobile phone affects cerebral blood flow in humans.
Huber R et al. (2005): Exposure to pulse-modulated radio frequency electromagnetic fields affects regional cerebral blood flow.
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.