Abstract
The acute effects of radiofrequency electromagnetic fields (RF EMF) on human cognitive performance were investigated. Cognitive tasks were identified from RF EMF cognitive research; tests used most extensively were psychomotor performance, attention, working and episodic memory tasks. Review of published imaging research enabled selection of a battery of cognitive tasks for use in the experimental studies. Effects of practice and the test-retest reliabilities on the tests were evaluated and the relationship between the tests within the battery and measures of ability and personality investigated. Three studies were conducted to identify whether RF EMF produced by occupational communication systems had reliable effects on cognitive performance and self-reports of mood, anxiety and workload. Double-blind repeated measures design was used to investigate the following fields in comparison to sham; a high frequency (HF) 29MHz continuous wave (CW) signal, a very high frequency (VHF) 75MHz CW field, an Ultra High Frequency (UHF) modulated 448MHz field, a UHF 1206MHz CW signal and a TETRA 388MHz field pulse modulated at 17.6Hz. The first study demonstrated no significant effects of the VHF signal on performance when compared to sham. The HF signal appeared to reduce response time to two of the cognitive tasks and affect error rate on one of them. Investigation of the two UHF signals showed no reliable differences between conditions on the cognitive measures. The third study showed reliable differences between TETRA exposure and sham conditions on two of the tasks. Overall the results indicate that RF EMF signals at the frequencies and power levels used in these studies are well tolerated in healthy subjects. In general, the signals do not appear to have reliable and robust effects on human cognitive performance. However, there may be subtle transitory effects of RF EMF that are not well understood at the present time.