Medical/biological study (experimental study)

Thermal effects of mobile phone RF fields on children: A provocation study med./bio.

By: Lindholm H, Alanko T, Rintamäki H, Kännälä S, Toivonen T, Sistonen H, Tiikkaja M, Halonen J, Mäkinen T, Hietanen M

Published in: Prog Biophys Mol Biol 2011; 107 (3): 399-403

Aim of study (acc. to author)

To examine thermal and local blood flow responses in the head of pre-adolescent during exposure to a GSM mobile phone.

Background/further details

26 boys, aged 14-15 years, took part in this study. After 5 minutes baseline the boys were 15 minutes either sham exposed or exposed, in each case followed by a 5 minutes wash out period (no exposure). Then, the boys, previously exposed, were sham exposed for 15 minutes, whereas the boys, previously sham exposed, were exposed for 15 minutes. The session ended with a 5 minutes recovery period (no exposure).

Endpoint

thermoregulation: head temperature

Exposure

- 902.4 MHz
- mobile communications
- digital mobile phone
- GSM

Exposure	Parameters
Exposure 1: 902.4 MHz Modulation type: pulsed Exposure duration: continuous for 15 min	SAR: 0.99 W/kg average over mass (1 g) (brain) SAR: 0.66 W/kg average over mass (10 g) (brain) SAR: 4.3 W/kg average over mass (1 g) (head) SAR: 2 W/kg average over mass (10 g) (head)

Exposure 1

Main characteristics

Frequency	902.4 MHz
Type	electromagnetic field
Exposure duration	continuous for 15 min

Modulation

Modulation type	pulsed
Pulse width	0.577 ms
Additional info	pulse repetition time: 4.615 ms

Exposure setup

Exposure source	Nokia 6110 GSM mobile phone
Distance between exposed object and exposure source	4 mm
Setup	two GSM phones placed near each ear; only the right phone transmitting; transmitter of the phone deactivated, battery removed and antenna input replaced by an external coaxial cable; exposure executed in a temperature controlled climate chamber
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	0.99 W/kg	average over mass	calculated	1 g	brain
SAR	0.66 W/kg	average over mass	calculated	10 g	brain
SAR	4.3 W/kg	average over mass	calculated	1 g	head
SAR	2 W/kg	average over mass	calculated	10 g	head

Exposed system:

human
partial body: head (right ear)

Methods Endpoint/measurement parameters/methodology

effects on the cardiovascular system: peripheral blood circulation (electrocardiogram and digital blood pressure measurement), cerebral blood flow (changes in deoxyhemoglobin and oxyhemoglobin content, functional near-infrared spectroscopy)
thermoregulation: skin temperature changes (thermistors), facial skin temperature changes (infrared camera), temperature changes in the ear canal (temperature probe)

Investigated system:

investigation on living organism

Investigated organ system:

Time of investigation:

before exposure
during exposure
after exposure

Main outcome of study (acc. to author)

The authors did not find a temperature change in the ear canal due to exposure to a GSM mobile phone. The superficial temperatures of the head decreased during the experiment in both groups, exposed and sham exposed. The cerebral blood flow did not differ between the sham exposure and the exposure periods. No changes in the oxyhemoglobin and deoxyhemoglobin contents were observed during the sham exposure and exposure periods. The blood pressure decreased during the whole test session in sham exposed and exposed groups.
The authors conclude that a short term exposure to a GSM mobile phone does not cause any significant increase in local ear temperatures or superficial cerebral blood flow among pre-adolescent boys.

Study character:

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

Study funded by

Tekes (National Technology Agency), Finland

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