Cognitive Effects of Electromagnetic Fields in Humans

Abstract

Electromagnetic fields interact with human tissue in a number of ways, depending on power level and frequency, and have been long suspected by some to give rise to harmful effects. In particular, the use of a mobile phone against the head has aroused suspicions of various cognitive effects. Accordingly, there have been a large number of studies of behavioural effects from ELF, RF and microwave exposure, mostly as provocation experiments. This chapter discusses the ways and means of doing this, the confusion of physiological effects variously observed and the problem of inconsistency of results. In animal studies, exposure levels have been sufficient to elicit responses, which largely appear to be related to heating effects, whereas similar studies are not ethically easy in humans. Accordingly, many of the studies have sought to explore non-thermal responses, mediated either through induced currents in neurological tissue or biochemical responses directly in cells. Effects reported for ELF tend to be dissimilar to those for RF and this may be more to do with the physical interaction with tissue than anything more fundamental. It is the possible existence of non-thermal effects that has largely been considered here and also the problem of studies in children who have been urged to restrain mobile phone use. Some important consequences have been observed such as the effect of phone use on driving, but largely the conclusion of detailed provocation studies is that short term or acute exposure to ELF or RF within the established guidelines may not be a hazard to humans, which suggests that the increasing use of RF technology may not itself be harmful.