Medical/biological study (experimental study)

[Investigation of Cerebro-Biological Effects in Low-Frequency Pulsed RF Fields] med./bio.

Untersuchung biologisch-zerebraler Effekte in niederfrequent gepulsten Hochfrequenzfeldern

By: Eibert T, Hansen V, Kammerer H, Vaupel T

Published in: Frequenz 1997; 51 (11-12): 276-279

Journal

Aim of study (acc. to author)

To investigate the possible effects of the electromagnetic fields on the human cerebral functions using a commercial GSM mobile phone.

Background/further details

In this study 52 subjects (aged 20 to 38) were investigated.

Endpoint

cognitive/behavioral endpoints: memory, learning efficiency

Exposure

- mobile communications
- GSM

Exposure	Parameters
Exposure 1: 914 MHz Modulation type: pulsed Exposure duration: continuous for 10 min	power: 7.41 W peak value (nominal 8 W) electric field strength: 40 V/m peak value

Exposure 1

Main characteristics

Frequency	914 MHz
Type	electromagnetic field
Exposure duration	continuous for 10 min

Modulation

Modulation type	pulsed
Repetition frequency	217 Hz
Additional info	random GSM signal

Exposure setup

Exposure source	cellular phone anechoic chamber in test mode
Distance between exposed object and exposure source	45 cm
Chamber	The RF-absorbing material had a return loss better than -20 dB above 450 MHz. The furniture in the room was made from wood.
Setup	The mobile phone was held by a plastic holder with the monopole antenna positioned horizontally above the head of the subject sitting in an armchair.
Sham exposure	A sham exposure was conducted.
Additional info	The EEG was recorded in three sections of 10 min each with exposure in the middle section. The neuropsychological tests were performed on subsequent days with or without exposure. The tests were carried out incompletely double-blind. Interference of the exposure field with the EEG recording was avoided by selecting a higher sampling rate at 500 Hz.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power	7.41 W	peak value	measured	-	nominal 8 W
electric field strength	40 V/m	peak value	measured	-	-

Additional parameter details

Interfering fields were measured in several cycles with a total duration of several hours with the aid of various broadband antennas. The magnetic field measured between 5 Hz and 10 MHz was below 326 nT at 50 Hz. The electric field measured between 9 kHz and 3 GHz was below 25 mV/m with short term peaks at 70 kHz and between 100 and 200 MHz.

Measurement and calculation details

The resulting field distribution in the test room was simulated using a local numerical program. The peak value of the electric field strength depending on the radial distance from the antenna was measured in an anechoic chamber using two identical calibrated monopole probes. The antenna distance from the head was adjusted not to exceed the applicable limit of DIN/VDE 0848 being 41.4 V/m at 914 MHz.

Exposed system:

human
partial body: head

Methods Endpoint/measurement parameters/methodology

effects on the neurological system: EEG
cognitive/behavioral endpoints: memory, learning efficiency (verbal learning, retentiveness tests)

Investigated system:

investigation on living organism

Investigated organ system:

brain/CNS

Time of investigation:

before exposure
during exposure
after exposure

Main outcome of study (acc. to author)

No significant impact of the electromagnetic field on the human EEG as well as on the cognitive performance could be observed.

Study character:

medical/biological study
experimental study
full/main study
incomplete double-blind study, intra individual comparative study

Study funded by

Forschungsgemeinschaft Funk e.V. (FGF) (Research Association for Radio Applications), Germany

Verrender A et al. (2016): Pulse modulated radiofrequency exposure influences cognitive performance
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