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

Abstract

There is extensive literature on possible effects of extremely low-frequency magnetic fields (ELF-MFs) on human cognitive functions. However, due to methodological deficits (e.g., low statistical power, small sample sizes) findings have been inconsistent. In the current study we try to overcome these problems by carrying out a meta-analysis. Literature research revealed 17 studies. Nine of these were included in the meta-analysis because they fulfilled minimum requirements (e.g., at least single-blind experimental study design and documentation of means and standard deviation of the dependent variables). All of the studies used a 50 Hz magnetic field exposure. Small but significant effect sizes could be detected in two cognitive dimensions: in the hard level of visual duration discrimination, task-exposed subjects performed better than controls; at the intermediate level however, exposed subjects performed worse. Additionally, a significant improvement of correct responses was observed in the dimension of "flexibility" under exposure. However, due to the small number of studies per performance dimensions and the resulting instability of estimates, these findings have to be treated with extreme caution. Taken together, the results of the meta-analysis provide little evidence that ELF-MFs have any effects on cognitive functions.

Neuroprotective effects of lotus seedpod procyanidins on extremely low frequency electromagnetic field-induced neurotoxicity in primary cultured hippocampal neurons

“…Lipid peroxidation occurs when cells are in a state of oxidative stress, which can be detected by detecting the level of MDA. The colorimetric determination of MDA was based on the reaction of one molecule of the reactive aldehyde with two molecules of thiobarbituric acid at low pH (2)(3) and 95 C for 45 min. The resultant pink color was extracted by nbutanol, and the absorbance at 532 nm was determined with a microplate reader (Multiskan MK3, USA).…”

“…It has raised concern about their potential adverse health effects because people are increasingly exposed to ELF-EMF. Several studies have shown the influences of ELF-EMF on behavior [1], cognition [2] and neurophysiology [3].…”

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

“…Significant effects were found with the visual duration discrimination task at the hardest level (exposed individuals showing better performance) and at the intermediate level (exposed individuals showing poorer performance). Barth et al [2010] suggest treating the results with extreme caution due to the small number of studies per measurement parameter.…”

“…In addition, other differences found were studies with a low level of statistical power, inter-individual and inter-group differences, and variability in methodology, functional state of the nervous system, measurement parameters, and task difficulty. Given the inconsistent findings of work in this field, an Austrian group performed a meta-analysis on nine studies [Barth et al, 2010]. Significant effects were found with the visual duration discrimination task at the hardest level (exposed individuals showing better performance) and at the intermediate level (exposed individuals showing poorer performance).…”

Acute effects of mobile phone radiations on subtle energy levels of teenagers using electrophotonic imaging technique: A randomized controlled study

“…[34] Exposure to high power RF energies may lead to various health hazards ranging from neurocognitive deficits, autonomic abnormalities to brain cancers. [5678]…”