A Study on the Electrophysiological Disturbance of Brain after Electromagnetic Irradiation

ABSTRACT

Backgrounds To evaluate the effects of electromagnetic wave onto the nervous system, this study introduces a method to measure the EEG of rabbits exposed to microwave fields and analyze it in compliance with theoretical specific absorption rate (SAR) distribution in the head of the rabbit obtained from the simulation study. Furthermore, the effects of nimodipine and naloxone on the EEG during the electromagnetic irradiation were reported. METHODS: 1) EEG of 20 rabbits of 2 groups was measured before and after exposure to 2.45 GHz microwave with the power density of 10 dBm and 20 dBm respectively for 10 minutes and compared with those of another 10 rabbits which have not been exposed. The result was compared with the simulation of the distribution of SAR in the 3-layered sphere model approximated from the head of rabbit 2) Another 10 rabbits were intravenously given with nimodipine before and during the irradiation. 3) Naloxone (0.25 mg/kg) was given to the other 10 rabbits which have given repeatedly exposure to microwave (twenty daily 10 min sessions). Results: The simulation of SAR distribution depicted the presence of hot-spot situated around the rabbit's thalamus and brainstem. Higher field energy of microwave (20 dBm) induced a total power reduction indicative of CNS activation and a decrease in power distribution in the delta band and an increase In the alpha and beta bands in a significant manner(P(0.05). The changes were not reversed by nimodipine-treatment. Wllen naloxone injected, 2 rabbits showed periodic theta rhythms and a clinical seizure occurred in a rabbit. Conclusion: The EEG changes suggest that microwave can alter neuronal activities in the brain, especially thalamus and brainstem. The effects may be thermal in nature arid microwave irradiation shares a common mechanism with physical and psychological stresses that also precipitate seizures.