Auteurs

Kwon MS, Jääskeläinen SK, Toivo T, Hämäläinen H. No effects of mobile phone electromagnetic field on auditory brainstem response. Bioelectromagnetics. Jul 16, 2009 Ahead of print.

Background
The increased use of mobile phones in proximity to the ear prompted investigations on possible effects of electromagnetic fields (EMF) on the auditory system.  No measurable changes have been found in otoacoustic emissions from the cochlea following short-term and long-term exposure to mobile phone EMF, with the exception of one study which documented a delayed latency in the auditory brainstem response (ABR), which is a brainstem auditory evoked potential that follows brief acoustic stimuli.  The present study used concurrent exposure and ABR measurements with the phone in a realistic position over the ear.

Methods
The study population consisted of 17 participants (11 females). The ABR recordings were carried out in accord with routine clinical ABR recording procedures in soundproof labs designed for using clinical-evoked potential measurements. Each participant was lying relaxed on a reclining chair with eyes closed. Both ears were stimulated one at a time, first the right then the left, under three different conditions: without a mobile
phone (baseline) and then with a mobile phone placed on the stimulated ear, either emitting EMF (EMF-on) or not (EMF-off).  Exposure was set to produce the same EMF emitted by an ordinary GSM mobile phone: 902.4MHz EMF with the mean power of 0.25W, pulsed at a frequency of 217 Hz with a pulse width of 0.58 milliseconds. The amplitudes, latencies, and interwave intervals of the main ABR components (waves I, III, and V) were measured and analyzed for possible EMF effects using repeated measures ANOVA.

Results
Participants reported that they had used mobile phones for 7.3+/-2.0 years on average, 4.2+/-2.7 times per day, and talked a total of 17.4+/-14.5 min per day, 4.9+/-4.7 min each time. The main effect of exposure condition was not significant except for the latency of wave I.  However, post hoc comparisons showed this was due to the mean latency in the baseline condition being slightly but significantly shorter than that in the other two conditions. There was no statistically significant difference in the wave I latency between EMF-off and EMF-on conditions.

Discussion and Conclusion
ABR waveforms showed no significant differences due to exposure, suggesting that short-term exposure to mobile phone EMF did not affect the transmission of sensory stimuli from the cochlea up to the midbrain along the auditory nerve and brainstem auditory pathways.  This provided further support of previous findings.


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