Study type: Medical/biological study (experimental study)

Effect of Bluetooth headset and mobile phone electromagnetic fields on the human auditory nerve. med./bio.

Published in: Laryngoscope 2014; 124 (1): 255-259

Aim of study (acc. to author)

To examine whether the use of a Bluetooth headset reduces the mobile phone-exposure related effects on the human auditory nerve as detected in a previous study of the authors (Colletti et al. 2011).

Background/further details

In the previous study, patients suffering from Menière's disease and undergoing retrosigmoid vestibular neurectomy were exposed to electromagnetic fields generated by a mobile phone. The patients showed a substantial significant decrease in amplitude and a significant increase in latency of cochlear nerve compound action potentials during the 5 minutes of exposure to the electromagnetic field.
In the present study, 12 patients, also suffering from Menière's disease and undergoing retrosigmoid vestibular neurectomy, were directly exposed to a mobile phone or alternatively via a Bluetooth headset (6 patients, respectively).

Endpoint

Exposure

Exposure Parameters
Exposure 1: 900 MHz
Exposure duration: continuous for 5 min
  • SAR: 0.82 W/kg maximum (10 g) (according to manufacturer)
Exposure 2: 2.4 GHz
Exposure duration: continuous for 5 min
Bluetooth headset

General information

Cochlear compound action potentials were first recorded with the cell phone in standby mode for 2 minutes and then continuously monitored during 5 minutes of active call (either via the Bluetooth headset or directly exposed to the mobile phone)

Exposure 1

Main characteristics
Frequency 900 MHz
Type
Exposure duration continuous for 5 min
Additional info mobile phone
Exposure setup
Exposure source
Setup mobile phone positioned over the craniotomy area
Parameters
Measurand Value Type Method Mass Remarks
SAR 0.82 W/kg maximum - 10 g according to manufacturer

Exposure 2

Main characteristics
Frequency 2.4 GHz
Type
Exposure duration continuous for 5 min
Additional info Bluetooth headset
Exposure setup
Exposure source
Setup Bluetooth headset positioned over the craniotomy area, mobile phone lying approximately 50 cm away
Parameters
Measurand Value Type Method Mass Remarks
power 2.5 mW maximum - - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

The directly mobile phone exposed patients showed a significant decrease in the amplitude and a significant increase in latency of cochlear nerve compound action potentials from the second to the fifth minute of exposure. The patients exposed via bluetooth showed no statistically significant changes in the latency and the amplitude of cochlear nerve compound action potentials. Between both groups, the analysis of the acoustic evoked brainstem potentials performed on wave V showed no statistically significant differences. Postoperative audiological follow-up revealed no significant hearing threshold deterioration in any of the patients.
The authors conclude that the electromagnetic fields produced by a bluetooth headset do not induce changes in the activity of the cochlear nerve, whereas direct exposure to a mobile phone could change the activity.

Study character:

Study funded by

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