Exposure to pulse modulated radiofrequency electromagnetic fields does not affect Sternberg working memory performance

Purpose: To replicate a previously reported finding that radiofrequency electromagnetic field (RF-EMF) exposure improves performance on the Sternberg working memory task, as indicated by decreased reaction time, and to test whether this effect, if verified, can also be induced by exposure to an infrared electromagnetic field (IR-EMF). Materials and methods: Forty-eight healthy adults participated in a randomized, counterbalanced provocation study. Working memory performance was assessed using a modified Sternberg working memory task, which was calibrated to individual performance levels in a preliminary testing session. An sXh920 planar exposure system was used to generate a 920 MHz GSM-like signal, providing two double-blind conditions (peak-spatial SAR average over 10 g) of 0 W/kg (Sham) and 2 W/kg (RF-EMF). A standard, ‘off the shelf’ 250 W infrared globe provided an IR-EMF exposure with an equivalent heating profile over the skin as that due to the RF-EMF exposure (circa 0.3 °C). Results: RF-EMF exposure did not reduce reaction time in the Sternberg working memory task. Exploratory tests also revealed there was no effect of IR-EMF on reaction time, and no other performance measures (response bias and response discrimination) were affected by either RF-EMF or IR-EMF exposure. Conclusions: The current study found no evidence that acute exposure to RF-EMF decreases reaction time on a Sternberg working memory task. The failure to replicate our previously reported effect of RF-EMF exposure on reaction time indicates that our initial finding was not an effect of RF-EMF exposure and was likely due to chance.