A meta-analysis for neurobehavioural effects due to electromagnetic field exposure emitted by GSM mobile phones

Background and objective: Numerous studies have investigated the potential effects of electromagnetic fields (EMFs) emitted by GSM mobile phones (similar to 900 MHz to similar to 1800 MHz) on cognitive functioning, but results have been equivocal. In order to try and clarify this issue, the current study carried out a meta- analysis on 19 experimental studies. Design: Meta-analysis. Methods: Nineteen studies were taken into consideration. Ten of them were included in the meta-analysis as they fulfilled several minimum requirements; for example, single-blind or double-blind experimental study design and documentation of means and standard deviation of the dependent variables. The meta-analysis compared exposed with non-exposed subjects assuming that there is a common population effect so that one single effect size could be calculated. When homogeneity for single effect sizes was not given, an own population effect for each study and a distribution of population effects was assumed. Results: Attention measured by the subtraction task seems to be affected in regard to decreased reaction time. Working memory measured by the N-back test seems to be affected too: under condition 0-back target response time is lower under exposure, while under condition 2-back target response time increases. The number of errors under condition 2-back non-targets appears to be higher under exposure. Conclusion: Results of the meta-analysis suggest that EMFs may have a small impact on human attention and working memory.