To replicate a previous study (publication 3600) and thus to assess whether the earlier findings on the effects of electromagnetic fields were replicable. The possible effects of electromagnetic field exposure on human brain electric oscillatory activity (ERD/ERS,- ERD/ERS is a pattern in the EEG signal, that shows functional alterations of neuronal networks) were examined utilizing the same memory task as used in the previous study.
EEG data analyses were conducted identically to the previous report and comprised of ERD/ERS analyses of the 4-6 Hz, 6-8 Hz, 8-10 Hz and 10-12 Hz EEG frequency bands. EEG frequencies are subdivided into frequency bands. The simultaneously recorded responses of different EEG frequency bands differ from each other and reflect different cognitive and/or mental processes.
|Exposure duration||continuous for 30 min|
|Pulse width||0.577 ms|
|Repetition frequency||217 Hz|
|Distance between exposed object and exposure source||40 mm|
|Chamber||The subject was seated in a comfortable chair in a dimmed registration room and was instructed to look at a TV screen placed 1.5 m in front of him/her and to avoid unnecessary eye movements.|
|Setup||A digital GSM phone was mounted to the subject's head over the left posterior temporal region positioned in direct contact to the left cheek in a normal use position. The antenna was located about 40 mm from the head. The phone was operated via a computer from an adjacent room.|
|Additional info||Each EEG test session was subdivided into two segments, with or without EMF in double-blind, counterbalanced order. The total testing time was about 60 min.|
The authors were not able to replicate the findings from the earlier study. All significant changes in the earlier study were not significant in the present double-blind study. Also, the effect of electromagnetic field radiation on the number of incorrect answers in the memory task was inconsistent. The authors previously reported no significant effect of electromagnetic field exposure on the number of incorrect answers in the memory task, but a significant increase in errors was observed in the present study. The only consistent finding between the present and the previous study was that in both studies electromagnetic fields decreased the magnitude or the ERS responses in the 4-6 Hz frequency band. The authors conclude that electromagnetic field effects on the EEG and on the performance on memory tasks may be variable and not easily replicable for unknown reasons.