Auteurs

Okano T, Terao Y, Furubayashi T, Yugeta A, Hanajima R, Ugawa Y. The effect of electromagnetic field emitted by a mobile phone on the inhibitory control of saccades. Clin Neurophysiol. Jan 16, 2010 Ahead of print.

Background
Though their findings are controversial, some studies suggest that electromagnetic fields (EMFs) from mobile phones may influence cognitive brain function, especially attention. It has been demonstrated that visual-spatial attention is controlled by essentially the same cortical structures as control eye movements (e.g. saccades). Earlier, the authors reported that 30-minute exposure to mobile phone had no effect on subject performance on elementary and simple saccade paradigms, which suggest that the cortical structures responsible for saccades and attention are not affected by EMF exposure from mobile phones. Oculomotor paradigms that require both initiation and inhibition of saccades depending on the behavioural context may be more sensitive to EMFs.

Objective
The objective was to study the effects of EMFs from a digital mobile phone on the inhibitory cortical functions of the brain using oculomotor paradigms.

Methods
Participants were 10 healthy right-handed subjects (3 men and 7 women, mean age 35.2±7.5 years, age range 24-47 years). Pulsed EMF (1.95 GHz) was delivered through a handset connected to a cellular phone simulator. During the 30 minute exposure period, the handset was held over the left ear at 2 cm from the scalp. Saccades were measured by means of electrooculography (EOG). A personal computer was used to control the visual stimulus and to acquire data. The participants’ performance on 4 tasks was assessed: the antisaccade (AS) task, the cued saccade (CUED) task, and 2 overlap saccade tasks (OL1 and OL2). A double-blind counterbalanced crossover design was used. Each subject’s performance before exposure was compared with his/her own performance after exposure. All subjects underwent 2 sessions: one before and one after exposure (real or sham). The subjects were unaware of which exposure condition was being used. One of the experimenters controlled the cellular phone simulator and the other implemented the saccade task.

Results
Most of the parameters of saccades in the 4 relatively complex oculomotor tasks remained unchanged after either real or sham exposure. The following changes were observed after exposure (real or sham): a significant shortening of latency in the CUED and OL2 tasks, a decrease in saccade amplitude on the antisaccade task and in saccade velocities of the antisaccade, cued saccade, and overlap saccade (OL1) tasks.

Interpretation and Conclusion
Thirty-minute exposure to EMF from a mobile phone had no significant effect on the inhibitory control of saccades. These results suggest that the cortical structures controlling both saccades and attention were not affected by the exposure.



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