Medical/biological study (experimental study)

Effects of cellular phone use on ear canal temperature measured by NTC thermistors med./bio.

By: Tahvanainen K, Nino J, Halonen P, Kuusela T, Alanko T, Laitinen T, Lansimies E, Hietanen M, Lindholm H

Published in: Clin Physiol Funct Imaging 2007; 27 (3): 162-172

Aim of study (acc. to author)

To measure temperature changes in the ear canal before, during and after a 35 min radiofrequency exposure for the two European cellular phone operational frequencies (900 and 1800 MHz).

Background/further details

30 healthy subjects participated. Temperature was measured by using small-sized NTC thermistors placed in the ear canals through ear plugs.
Temperature changes were determined 1) during a 5-min controlled breathing test, 2) during a 5-min spontaneous breathing test, 3) during 7-min head-up tilt test, 4) 1-min before, during and after two consecutive Valsalva's maneuvers and 5) during a deep breathing test.

Endpoint

thermoregulation: ear canal temperature

Exposure

- mobile communications
- digital mobile phone
- GSM

Exposure	Parameters
Exposure 1: 900 MHz Modulation type: pulsed Exposure duration: continuous for 35 min	power: 2 W peak value power: 0.25 W mean SAR: 1.58 W/kg maximum
Exposure 2: 1,800 MHz Modulation type: pulsed Exposure duration: continuous for 35 min	power: 1 W peak value power: 0.125 W mean SAR: 0.7 W/kg maximum

General information

Subjects in this double-randomised, double-blind, and placebo controlled crossover study were exposed on two different days, one week apart, to 900 MHz and 1800 MHz mobile phones.

Exposure 1

Main characteristics

Frequency	900 MHz
Type	electromagnetic field
Exposure duration	continuous for 35 min

Modulation

Modulation type	pulsed

Exposure setup

Exposure source	cellular phone dual band, connected to a notebook PC
Setup	Two mobile phones were located symmetrically leaning on the ears by means of a plastic helmet. The active phone was positioned on the dominant hand side of the head, and the phone on the other side was a dummy without battery.
Sham exposure	A sham exposure was conducted.
Additional info	The total duration of each session was 2 h including one 35-min RF and one 35-min sham exposure.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power	2 W	peak value	-	-	-
power	0.25 W	mean	-	-	-
SAR	1.58 W/kg	maximum	measured	-	-

Measurement and calculation details

Two specially designed antennas connected to MW detectors were placed at 20 cm from the active phone to measure the relative field intensities. SAR measurements were performed at both frequencies using a head phantom filled with tissue equivalent liquid and a DASY3 robotic RF scanner moving in a volume of 7 x 7 x 7 cm³ in the vicinity of the phone [Tahvanainen et al., 2004].

Exposure 2

Main characteristics

Frequency	1,800 MHz
Type	electromagnetic field
Exposure duration	continuous for 35 min

Modulation

Modulation type	pulsed

Exposure setup

Exposure source	same setup as exposure 1
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power	1 W	peak value	-	-	-
power	0.125 W	mean	-	-	-
SAR	0.7 W/kg	maximum	measured	-	-

Reference articles

Tahvanainen K et al. (2004): Cellular phone use does not acutely affect blood pressure or heart rate of humans

Exposed system:

human
partial body: head (ear)

Methods Endpoint/measurement parameters/methodology

thermoregulation: ear canal temperature (NTC thermistors)

Investigated system:

investigation on living organism

Investigated organ system:

Time of investigation:

before exposure
during exposure
after exposure

Main outcome of study (acc. to author)

Temperatures in the exposed ear were significantly higher during radiofrequency exposures compared with sham exposure with maximum differences of 1.2 +/- 0.5°C (900 MHz) and 1.3 +/- 0.7°C (1800 MHz). Temperatures in the exposed ear were also significantly higher during the post-exposure period compared with post-sham exposure period.
The data indicate that radiofrequency exposure to a cellular phone, either using 900 MHz or 1800 MHz with their maximal allowed antenna powers, increases the temperature in the ear canal (as a consequence of mobile phone battery warming during maximal antenna power use).

Study character:

medical/biological study
experimental study
full/main study
double-blind study, crossover study (placebo controlled)

Study funded by

Tekes (National Technology Agency), Finland

Loos N et al. (2013): Is the effect of mobile phone radiofrequency waves on human skin perfusion non-thermal?
Bortkiewicz A et al. (2012): Changes in tympanic temperature during the exposure to electromagnetic fields emitted by mobile phone
Lindholm H et al. (2011): Thermal effects of mobile phone RF fields on children: A provocation study
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Paredi P et al. (2001): Local vasodilator response to mobile phones
Bernardi P et al. (2000): Specific absorption rate and temperature increases in the head of a cellular-phone user
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Van Leeuwen GM et al. (1999): Calculation of change in brain temperatures due to exposure to a mobile phone
Adair ER et al. (1999): Human exposure at two radio frequencies (450 and 2450 MHz): similarities and differences in physiological response
Anderson V et al. (1995): Specific absorption rate levels measured in a phantom head exposed to radio frequency transmissions from analog hand-held mobile phones

Effects of cellular phone use on ear canal temperature measured by NTC thermistors med./bio.

Aim of study (acc. to author)

Background/further details

Endpoint

Exposure

General information

Exposure 1

Main characteristics

Modulation

Exposure setup

Parameters

Measurement and calculation details

Exposure 2

Main characteristics

Modulation

Exposure setup

Parameters

Reference articles

Methods Endpoint/measurement parameters/methodology

Main outcome of study (acc. to author)

Study funded by

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