Medical/biological study (experimental study)

Effects of thirty-minute mobile phone use on visuo-motor reaction time med./bio.

By: Terao Y, Okano T, Furubayashi T, Ugawa Y

Published in: Clin Neurophysiol 2006; 117 (11): 2504-2511

Aim of study (acc. to author)

To study whether exposure to pulsed radiofrequency electromagnetic field emitted by a mobile phone has short-term effects on the visuo-motor choice reaction time and movement time.

Background/further details

16 subjects participated. Within the choice reaction time task the subjects had to press one of two buttons with left or right hand as quickly as possible after the go-signal. A precue preceding this conveyed full, partial or no advance information (hand and/or button), such that reaction time shortened with increasing amount of information. The precuing effect has been taken to reflect motor preparation.

Endpoint

effects on the neurological system: effects on the visuo-motor choice reaction time and movement time

Exposure

- TDMA
- mobile communications
- digital mobile phone

Exposure	Parameters
Exposure 1: 800 MHz Modulation type: pulsed Exposure duration: continuous for 30 min	power: 0.8 W peak value power: 0.27 W mean SAR: 0.054 W/kg average over mass (10 g) (± 0.02 W/kg)

General information

The exposure setup was the same as described in [Arai et al., 2003].

Exposure 1

Main characteristics

Frequency	800 MHz
Type	electromagnetic field
Exposure duration	continuous for 30 min

Modulation

Modulation type	pulsed
Pulse width	6.7 ms
Repetition frequency	50 Hz
Additional info	3 channel TDMA with π/4 shifted quadrature phase-shift keying

Exposure setup

Exposure source	cellular phone handset connected to a communication tester, at maximum output
Distance between exposed object and exposure source	2 cm
Chamber	The subjects were comfortably seated in a chair.
Setup	The subjects held the handset over the right ear in a normal use position and spoke to one of the examiners through the air. The antenna was located about 2 cm from the head and 3 cm from the brain tissue. The auditory circuitry of the handset was disabled.
Sham exposure	A sham exposure was conducted.
Additional info	A double blind, counterbalanced crossover design was used. The sessions under real and sham exposure were separated by at least 7 days.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power	0.8 W	peak value	-	-	-
power	0.27 W	mean	-	-	-
SAR	0.054 W/kg	average over mass	measured	10 g	± 0.02 W/kg

Measurement and calculation details

SARs in the brain area (30 mm below the skull) were measured using a phantom system as recommended by IEC [2005] holding the handset at several positions, the results of which did not differ significantly.

Reference articles

Arai N et al. (2003): Thirty minutes mobile phone use has no short-term adverse effects on central auditory pathways

Exposed system:

human
partial body: head

Methods Endpoint/measurement parameters/methodology

effects on the neurological system: effects on the visuo-motor choice reaction time and movement time (visuo-motor precued choice reaction time task (see "background"); error rates)

Investigated system:

investigation on living organism

Investigated organ system:

brain/CNS

Time of investigation:

before exposure
after exposure

Main outcome of study (acc. to author)

The reaction times and movement times under different conditions of precue information were not affected by exposure to the cell phone or by sham exposure. In conclusion, 30 minutes of mobile phone use has no significant short-term effect on the cortical visuo-motor processing.

Study character:

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

Study funded by

Association of Radio Industries and Businesses (ARIB), Japan
Committee to Promote Research on the Possible Biological Effects of Electromagnetic Fields, Japan
Ministry of Internal Affairs and Communications, Japan

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