Authors
Parazzini M, Lutman ME, Moulin A, Barnel C, Sliwinska-Kowalska M, Zmyslony M, Hernadi I, Stefanics G, Thuroczy G, Ravazzani P. Absence of Short-Term Effects of UMTS Exposure on the Human Auditory System. Rad Research. Nov 18 2009 Ahead of print.

Background
The ear may be especially vulnerable to the harmful effects of radiofrequency (RF) radiation emitted from mobile phones because mobile phones are usually held close to the ear, and the external ear may provide a natural route for RF radiation to reach and potentially damage the auditory structure.  One previous study found no effect of GSM mobile phone exposure on the auditory system.  However the new UMTS standard is now in use for 3G phones and there still exists concern regarding UMTS exposure and effects on hearing.

Objective
In 2004, the European Commission established the project EMFnEAR to investigate the effects of UMTS exposure on hearing.  This paper describes some of the project results.

Methods
Participants were healthy adults 18-30 years of age who were screened for hearing or ear disorders and were found to be otologically normal.  The assessment of auditory function was based on a standard battery of tests used for assessing hearing function in clinics.  The protocol consisted of the following tests: hearing threshold level (HTL) to measure hearing loss; distortion product otoacoustic emissions (DPOAE) as a measure of inner ear health; contralateral acoustic stimulation during transiently evoked otoacoustic emissions (CAS effect on TEOAE) to measure the connection between the auditory system and the outer ear; and auditory evoked potentials (AEP) to measure nervous system processing of auditory information.  Auditory function was assessed immediately before and after 20 minute exposure to RF radiation.  The procedure was conducted twice, once with a real and once with a sham exposure and both the test participant and the tester were blind to the condition being tested.  Exposure and testing were always conducted on the same ear.  The right or left ear was selected based on whichever ear scored better in the screening session.  Participants performed an attention task (such as counting the number of times a word occurred in the speech material) to ensure that the participant was focusing on the speech material.  The exposure system was mounted on the side of the participants’ head.

Results
A total of 73 subjects (38 women, 35 men), participated in the study.  There were no statistically significant differences in any of the auditory tests before and after exposure.

Interpretation and Limitations
Two recent papers used EMFnEAR data to look at the effects of UMTS RF exposure on auditory function and found no significant difference before and after exposure.  The present study is the first to use high and localized levels of exposure to assess the effects on hearing function in humans.  The authors found no evidence of adverse effects on the main audiological measures for short-term exposure at a maximum specific absorption rate (SAR) of 1.75 W/kg averaged over 1g at 1947 MHz, an exposure level far above that usually associated with commercially available mobile phones, which is in line with results found in laboratory animals.  This study was not able to assess the long-term effects of RF exposure on auditory function.

Conclusion

The authors conclude that RF radiation at the level and for the duration used in the present study does not cause physiological effects in the human auditory system.


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