Study type: Medical/biological study (experimental study)

Electromagnetic field of mobile phones affects visual event related potential in patients with narcolepsy med./bio.

By: Jech R, Sonka K, Ruzicka E, Nebuzelsky A, Böhm J, Juklickova M, Nevsimalova S
Published in: Bioelectromagnetics 2001; 22 (7): 519-528
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Aim of study (acc. to author)

To examine the effects of the mobile phone electromagnetic fields on EEG and event-related potentials. The aim was to study in particular patients with narcolepsy in an effort to explore the interaction between vigilance and the effects of the pulsed mobile phone field. In a double-blind study, these patients had the visual event-related potentials recorded during their 45 min exposure.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 900 MHz
Modulation type: pulsed
Exposure duration: continuous for 45 min
  • power: 2 W maximum
  • SAR: 0.06 W/kg maximum (10 g)

Exposure 1

Main characteristics
Frequency 900 MHz
Type
Exposure duration continuous for 45 min
Modulation
Modulation type pulsed
Pulse width 0.577 ms
Repetition frequency 217 Hz
Additional info

modulation frequency components 2 and 8 Hz
Exposure setup
Exposure source
Chamber The patients were examined in the supine position in a darkened room.
Setup The mobile phone was fixed to the right ear using a special holder. The phone was thermally insulated from the head with a textile case and the electrode cap. It was not possible to recognise the state of exposure.
Additional info The patients were examined in a double blind study on two successive days with 50% of them per day being exposed or sham exposed.
Parameters
Measurand Value Type Method Mass Remarks
power 2 W maximum - - -
SAR 0.06 W/kg maximum measured and calculated 10 g -
Additional parameter details

The SAR value was measured without casing and electrode cap.

Measurement and calculation details

The SAR was determined in keeping with CENELEC by means of a spherical liquid filled phantom, 20 cm in diameter, with the phone at a distance of 5 mm. The measurement was performed at the max. absorbed power location (hot spot) using a 3D guided calibrated probe terminating in three perpendicular dipoles.

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • during exposure
  • after exposure

Main outcome of study (acc. to author)

There were no alterations of the EEG recorded after the mobile phone exposure. The reaction time was shortened by 20 ms in response to all target stimuli. The mobile phone field might effectively inhibit the excessive sleepiness which is assumed to be, in narcolepsy, an active process. This may correspond with evidence of improved performance while solving monotonous cognitive task requiring sustained attention. With regard to the fact that the subjects of the group were exclusively patients with narcolepsy, it is difficult to decide whether the mobile phone exposure's positive effect on visual event-related potential was due to the narcoleptics' enhanced sensibility or whether this was the result of the general effects of a high frequency electromagnetic field associated with the given type of cognitive task.

Study character:

Study funded by

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