Medical/biological study (experimental study)

Effect of 902 MHz mobile phone transmission on cognitive function in children med./bio.

By: Preece AW, Goodfellow S, Wright MG, Butler SR, Dunn EJ, Johnson Y, Manktelow TC, Wesnes K

Published in: Bioelectromagnetics 2005; 26 Suppl 7: S138-S143

Aim of study (acc. to author)

To study whether a standard mobile phone exposure at 902 MHz has a significant effect on cognitive function in 18 children 10-12 years of age.

Background/further details

The children were in a single group in which each child was given a single training session and then three test sessions using the cognitive drug research cognitive assessment system.

Endpoint

cognitive/behavioral endpoints: cognitive function

Exposure

- mobile communications
- GSM

Exposure	Parameters
Exposure 1: 902 MHz Modulation type: pulsed Exposure duration: continuous for 30 min	power: 2 W peak value power: 0.25 W mean SAR: 0.28 W/kg maximum (brain) power: 0.2 W peak value power: 0.025 W mean

Exposure 1

Main characteristics

Frequency	902 MHz
Type	electromagnetic field
Exposure duration	continuous for 30 min
Additional info	Reference article: CENELEC. 2000. Basic standard for the measurement of specific absorption rate related to human exposure to electromagnetic fields from mobile phones (300 MHz to 3 GHz). Draft proposal l. European Committee for Electro-Technical Standardization.

Modulation

Modulation type	pulsed

Exposure setup

Exposure source	cellular phone
Chamber	Children sat in a quiet room with good uniform lighting and only the tester was present.
Setup	The phone in normal use position was placed in an acrylic cradle mounted on a plastic ear defender, replacing the earmuff on the left side. The phone was handed over after checking against a RF signal strength meter.
Additional info	Each child was given three test sessions on sequential days, in a randomized, three-way crossover design. During the power off mode (sham condition), the mobile phone was not on standby but switched off. The phone was modified by removing the audio transducer in order to prevent low level buzzing during high power operation.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power	2 W	peak value	measured	-	-
power	0.25 W	mean	measured	-	-
SAR	0.28 W/kg	maximum	measured and calculated	brain	-
power	0.2 W	peak value	measured	-	-
power	0.025 W	mean	measured	-	-

Measurement and calculation details

The phones were examined for maximum brain SAR and not the maximum tissue SAR on which the standards are based. Interaction was measured as the E field in an anatomical, uniform phantom, 10 mm into the homogeneous tissue equivalent material of ε = 40, σ = 0.86 S/m using a Schottky diode mounted on a 6 mm dipole antenna and calibrated in brain equivalent fluid [CENELEC, 2000].

Reference articles

Preece AW et al. (1999): Effect of a 915-MHz simulated mobile phone signal on cognitive function in man

Exposed system:

human
partial body: head

Methods Endpoint/measurement parameters/methodology

cognitive/behavioral endpoints: cognitive function (reaction time, accuracy, sensitivity; short-term memory; vigilance; working memory; cognitive drug research test)

Investigated system:

investigation on living organism

Investigated organ system:

brain/CNS

Time of investigation:

during exposure

Main outcome of study (acc. to author)

This findings showed trends toward faster reaction times, higher accuracy, and higher sensitivity in the presence of irradiation from a GSM mobile phone. However, none of these effects reached statistical significance. Although, the tests employed were very similar to those used in a previous study in adults (see publication 162) the effects seen in that study were not replicated. However, the present study investigated the effects of irradiation from a GSM mobile phone, whereas in the previous study the effect on reaction time was observed only with a more powerful analogue handset.

Study character:

medical/biological study
experimental study
full/main study
randomized, three-way cross-over study design

Study funded by

Charitable Trustees of the United Bristol Hospitals, Bristol, UK

Comments on this article

Lin JC (2005): Children's cognitive function and cell-phone electromagnetic fields

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