Effects of information and 50 Hz magnetic fields on cognitive performance and reported symptoms

Abstract

The aim of this study was to explore the role of expectancies and beliefs about the potential effects of electromagnetic fields (EMFs) (what the subject thought the effect was going to be) and the effects of 50 Hz magnetic fields (400 mT rms ) acute exposure on cognitive performance, the reporting of physical symptoms and some psychological and physiological parameters. Seventy-four healthy male volunteers aged between 40 and 60 years of age were randomly assigned to one of five groups, which differed in (1) the type of information they were given concerning the expected magnetic field effect on performance in cognitive tests (positive ¼ enhancement of the performance; negative ¼ impairment of the performance; neutral) and (2) the type of exposure (real or sham). Three groups were sham exposed with positive (groupþ), negative (groupÀ) and neutral information (groupþ/À); one group was really exposed with neutral information (group expo) and one group was not exposed, though they wore the helmet, and did not receive any field-related information (control group). All the volunteers, except the control group, were led to believe that they would be exposed to a magnetic field of 400 mT rms . The experimental design respected a double blind procedure and the experimental session involved three steps (pre-testing, exposure, and post-testing). Various measurements were taken, including cognitive performance, psychological parameters such as mood, vigilance, and reporting of symptoms. Physiological parameters such as blood pressure and pulse rate were also recorded. The information given did not significantly modify beliefs. No significant difference was found among the five groups depending on the type of information and the type of exposure in cognitive performance, psychological and physiological parameters. In the context of the study, with our population, the type of information given failed to induce expected changes in parameters measured. Our results do not support the hypothesis that an acute exposure to extremely low frequency magnetic fields (50 Hz, 400 mT rms ) affects the parameters measured.

Medicine‐related beliefs predict attribution of symptoms to a sham medicine: A prospective study

“…Whether some people are particularly predisposed to experiencing a nocebo effect remains unclear. Several potential predisposing factors have been suggested including gender (Liccardi et al ., 2004), anxiety (Nevelsteen, Legros, & Crasson, 2007), somatization (Szemerszky, Koteles, Lihi, & Bardos, 2010), somatosensory amplification (Witthöft & Rubin, 2013), low optimism (Geers, Helfer, Kosbab, Weiland, & Landry, 2005), and baseline symptoms (de la Cruz, Hui, Parsons, & Bruera, 2010). However, in a systematic review, Webster, Weinman, and Rubin (2016) highlighted inconsistent findings with regard to the importance of these factors.…”

Effects of extremely low‐frequency magnetic field exposure on cognitive functions: results of a meta‐analysis

“…But this result has to be treated with caution, since the heterogeneity conclusion is again driven by only one study [Preece et al, 1998: D ¼ À0.92], whereas none of the later studies on working memory (number) were able to replicate such an effect: Delhez et al [2004]: D ¼ 0.14 and Nevelsteen et al [2007]: D ¼ À0.07.…”

“…b Podd et al [2002], Crasson et al [1999], Preece et al [1998], Delhez et al [2004], Whittington et al [1996], Keetley et al [2001], Nevelsteen et al [2007], Kurokawa et al [2003].…”

“…h Preece et al [1998], Keetley et al [2001]. i Delhez et al [2004], Nevelsteen et al [2007]. j Podd et al [2002], Preece et al [1998].…”

Human cognitive performance in a 3 mT power-line frequency magnetic field

“…The most recent studies using sinusoidal 50 Hz MF (at 20, 100, or 400 mT) found no effects on working memory and cognitive flexibility [Delhez et al, 2004;Nevelsteen et al, 2007], selective and sustained attention tasks [Delhez et al, 2004;Crasson and Legros, 2005;Nevelsteen et al, 2007], and reaction time or time perception [Kurokawa et al, 2003;Delhez et al, 2004;Crasson and Legros, 2005]. However, a consistent effect appears to exist when the 50 Hz exposure level is >500 mT.…”