Impact of Microwave Exposure on Cynomolgus Monkeys: EEG and ECG Analysis

The annual increase of microwave exposure in human environments continues to fuel debates regarding its potential health impacts. This study monitored the EEG and ECG responses of three Cynomolgus monkeys before and at 0, 3, 7, 14, and 30 days after exposure to 50 mW/cm² microwave radiation for 15 min. The findings revealed no significant differences in the power spectral densities (PSDs) of the whole brain, frontal, and temporal lobes across various frequency bands (δ, θ, α, β, low-γ, and high-γ) immediately and up to 30 days postexposure. Notable alterations were observed primarily at 14 days in the PSDs of the parietal lobe, prefrontal cortex, central zone, and occipital lobe, particularly in the θ and α bands. By Day 30, these values returned to normal ranges. ECG alterations were characterized by changes in T-wave shape and amplitude. One monkey exhibited bidirectional spikes at 7 and 14 days that normalized by Day 30. Another showed similar patterns with reduced amplitude, and a third monkey displayed a towering forward wave at 14 days that persisted at 30 days. In conclusion, the administration of L-band microwave radiation at the specified dose did not result in immediate alterations to EEG and ECG, but it induced transient modifications in brain electrical activity and normalized after 30 days, which contributed to evaluate the health implications of microwave exposure in humans.