Medical/biological study (experimental study)

Examining the effects of electromagnetic fields emitted by GSM mobile phones on human event-related potentials and performance during an auditory task med./bio.

By: Hamblin DL, Wood AW, Croft RJ, Stough C

Published in: Clin Neurophysiol 2004; 115 (1): 171-178

Aim of study (acc. to author)

To explore the sensitivity of auditory event-related potentials to electromagnetic emissions.

Background/further details

The current study exposed subjects while they performed tasks, and employed a mobile phone with a substantial and consistent power output. In order to study alterations in sensory processing that may be produced by electromagnetic field exposure, the event-related potential parameters were assessed during an auditory oddball task.

Endpoint

effects on the neurological system: event-related potentials and performance during an auditory task

Exposure

- mobile communications
- digital mobile phone
- GSM

Exposure	Parameters
Exposure 1: 894.6 MHz Modulation type: pulsed Exposure duration: continuous for 1 h	power: 2 W peak value power: 250 mW mean SAR: 0.87 W/kg unspecified (unspecified) (at the head)

Exposure 1

Main characteristics

Frequency	894.6 MHz
Type	electromagnetic field
Exposure duration	continuous for 1 h

Modulation

Modulation type	pulsed
Pulse width	576 µs
Duty cycle	12.5 %
Repetition frequency	217 Hz

Exposure setup

Exposure source	cellular phone
Setup	Participants were seated in a comfortable chair with an electro-cap fitted (comprising 62 tin electrodes). A mobile phone in a cradle was placed over the right temporal region in a normal use position. Audio circuits were disabled and a padding was placed between the handset and its casing to prevent any acoustic or thermal cues. The mobile phone was set via lap-top to a nominal mean power output of 250 mW.
Additional info	There were two sessions one week apart, each with real or sham exposure for half of the participants in single-blind, counterbalanced, crossover conditions.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power	2 W	peak value	-	-	-
power	250 mW	mean	-	-	-
SAR	0.87 W/kg	unspecified	estimated	unspecified	at the head

Measurement and calculation details

In a separate test, a power meter at the phone's antenna connector measured the power output of the phone to make sure that the power would remain constant for at least one hour.

Exposed system:

human
partial body: head (ear)

Methods Endpoint/measurement parameters/methodology

effects on the neurological system: EEG; event-related potential during the auditory oddball task (N100, P200, N200, P300; analysis of averaged amplitude and latency figures)
cognitive/behavioral endpoints: reaction time and accuracy rate data during the auditory oddball task

Investigated system:

investigation on living organism

Investigated organ system:

Time of investigation:

during exposure

Main outcome of study (acc. to author)

The results suggest that mobile phone radiation may affect neural activity, particularly in proximity to the phone, however caution should be applied due to the small sample size. N100 amplitude decreased, N100 latency shortened and P300 latency was delayed during exposure compared to sham exposure. Effects were greatest over right hemisphere and midline sites (closest to the active mobile phone). Reaction time increased in the exposure relative to sham exposure condition and no difference in accuracy was found.

Study character:

medical/biological study
experimental study
pilot/exploratory/preliminary study

Study funded by

Telstra Research Laboratories (TRL), Australia

Replication studies

Hamblin DL et al. (2006): The sensitivity of human event-related potentials and reaction time to mobile phone emitted electromagnetic fields

Mohan M et al. (2016): Does chronic exposure to mobile phones affect cognition?
Mortazavi SM et al. (2012): Human short-term exposure to electromagnetic fields emitted by mobile phones decreases computer-assisted visual reaction time
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
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