19

Until recently, I have only heard about studies proving electrosensitivity being entirely a nocebo effect.

Now I just found out about a study:

Electromagnetic Field Sensitivity, William J. Real et al., 1991.

I have not myself read the study, but it claims it was a double blind test containing 16 subjects. 100% of the ones that were allergic responded to the electricity.

Are there any attempts to repeat the same study? Does it have any known critisism?  

29

Where you have a number of studies with conflicting results, it is time for a meta-analysis, which carefully combines a number of studies, to get a more statistically powerful sample.

This study was cited by a meta-analysis:

G. James Rubin, Jayati Das Munshi and Simon Wessely, Electromagnetic Hypersensitivity: A Systematic Review of Provocation Studies Psychosomatic Medicine 67:224-232 (2005), doi: 10.1097/​01.psy.0000155664.13300.64

Their abstract covers the territory very well:

Objectives: The objectives of this study were to assess whether people who report hypersensitivity to weak electromagnetic fields (EMFs) are better at detecting EMF under blind or double-blind conditions than nonhypersensitive individuals, and to test whether they respond to the presence of EMF with increased symptom reporting.

Perfect - that seems to be directly aimed at your question.

Results: Thirty-one experiments testing 725 "electromagnetically hypersensitive" participants were identified. Twenty-four of these found no evidence to support the existence of a biophysical hypersensitivity, whereas 7 reported some supporting evidence. For 2 of these 7, the same research groups subsequently tried and failed to replicate their findings. In 3 more, the positive results appear to be statistical artefacts. The final 2 studies gave mutually incompatible results. Our metaanalyses found no evidence of an improved ability to detect EMF in "hypersensitive" participants.

I'm not sure where the Real et al study fit in here, but if it gave a positive result, it was in the minority. (Although, it should also be considered by its sample size and methodological strength, which aren't covered by the numbers here.)

Conclusions: The symptoms described by "electromagnetic hypersensitivity" sufferers can be severe and are sometimes disabling. However, it has proved difficult to show under blind conditions that exposure to EMF can trigger these symptoms. This suggests that "electromagnetic hypersensitivity" is unrelated to the presence of EMF, although more research into this phenomenon is required.

So, nocebo appears to be a plausible explanation.

6
+250

An up-to-date analysis has been requested. I agree that it's desirable to integrate the study "Electromagnetic Hypersensitivity: Evidence for a Novel Neurological Syndrome" (McCarty et al. 2011) into a larger analysis. Another team, Rubin et al. were unable to replicate this study and complained to the journal about McCarty's poor controls, which launched a heated exchange of letters with each side accusing the other of poor conduct ("Letter to the Editor: Electromagnetic Hypersensitivity" International Journal of Neuroscience 2012). See this stats.SE question for further analysis.

In 2017, an edited scientific volume characterized McCarty's and other studies as follows:

To date, the results of provocation studies suggest that [self-described hypersensitivity] is not caused by exposure to EMFs (indeed, they do not provide any evidence that EMF exposure causes the reported symptoms). Yet, like epidemiological studies, provocation studies are challenged by several methodological limitations, some of which could potentially explain the inability of these studies to find an effect of exposure. One of these limitations relates to recruitment. Little is known about whether subsets of IEI‐EMF exist and so it is conceivable that the samples tested may have included a combination of both individuals who are sensitive to EMF and others who may suffer from unrelated conditions. This could result in a large amount of noise being added to the data, which would reduce statistical power and mask any real effects.

Verrender et al., Non-Ionizing Radiation Protection : Summary of Research and Policy Options, John Wiley & Sons, Incorporated, 2017. p.372.

Here is a new meta-analysis from 2016 that specifically discusses sensitivity to mobile base stations:

Klaps et al. "Mobile phone base stations and well-being--A meta-analysis." Sci Total Environ. 2016 Feb 15;544:24-30. doi: 10.1016/j.scitotenv.2015.11.009

The existing studies on this topic are highly inconsistent. In the current paper we attempt to clarify this question by carrying out a meta-analysis which is based on the results of 17 studies. Double-blind studies found no effects on human well-being. By contrast, field or unblinded studies clearly showed that there were indeed effects. This provides evidence that at least some effects are based on a nocebo effect. Whether there is an influence of electromagnetic fields emitted by mobile phone base stations thus depends on a person's knowledge about the presence of the presumed cause. Taken together, the results of the meta-analysis show that the effects of mobile phone base stations seem to be rather unlikely. However, nocebo effects occur.

In 2018, the Swedish Radiation Safety Authority published an overview of research from 2015 to 2017, "Recent Research on EMF and Health Risk". Pages 74-79 of this comprehensive overview discuss hypersensitivity. It concludes:

New publications on electromagnetic hypersensitivity, EHS, could not identify physiological characteristics that may help diagnose or develop effective therapeutic options.

It should be noted that this overview includes statistically significant health damages related to electronic devices -- however, the evidence is strong that factors other than RF-EMF are the cause. The authors of the overview analyze each of the EMF hypersensitivity studies and find that there are damaging health effects which are worth analyzing in terms other than "hypersensitivity":

... given the inconsistency in terms of EMF-exposure the authors concluded that the study does not support a link between RF-EMF exposure and sleep quality, but potentially other factors that are related to mobile phone usage may negatively affect the sleep of children.

There have also been additional studies not yet included in any published meta-analysis.

0

I found a recent study (2011): Electromagnetic Hypersensitivity: Evidence for a Novel Neurological Syndrome (McCarty, Carrubba, Chesson, Frilot, Gonzalez-Toledo & Marino).

To my untrained eyes, it looks very serious (double-blind, no conflict of interests, controlling for somatization, etc.). It also mentions the meta-analysis from 2005.

Some conclusions:

The subject developed symptoms in association with the presentation of a pulsed electric field significantly (p < .05) more often than could reasonably be explained on the basis of chance

And:

Our aim here was to concentrate on the previously unaddressed question whether acute exposure to weak EMF could produce real but not precisely predictable somatic effects mediated by nonpsychological processes. Within the limitations of the study, we concluded that we demonstrated the neurological syndrome in the subject we studied.

So, at this point, it seems there's a possibility that some people (3-5% of the population, maybe) are actually hypersensitive to electromagnetic fields and that cell towers, mobile phones, wireless access points, etc. might be a real problem (although more research is still needed).

  • 4
    While it would make sense for this study to be included in any future meta-analyses, the results of this study are rather weak. One person was tested. The p-values were never stated, and were only marginally significant (e.g. p<0.05), and then only in SOME of the tests. NOTE: I tried repeating the analysis of Experiment 3, using a two-tailed Chi Squared test (Fisher's Exact, and Chi-Squared with and without Yates correction). It does NOT appear to be significant. I'd appreciate it if someone more experienced at this would give it a go. – Oddthinking Oct 7 '12 at 10:11
  • "One person was tested." But with the proper methodology, one person would be enough to prove that electromagnetic hypersensitivity might be a real thing, right? Of course, that still wouldn't mean most people complaining about cell towers, etc. are not suffering from a nocebo effect. – Olivier Bruchez Oct 7 '12 at 19:53
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    Yes. Having only one person tested doesn't provide support for the "3-5% of the population" claim. It also increases the risk of conspiracy - i.e. that a hoax is being perpetrated against scientists unable to detect magic tricks. – Oddthinking Oct 8 '12 at 0:52
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    According to the paper itself "there was no requirement that the same symptom must reoccur when the EMF provocation was repeated" which sounds like an experiment designed to allow random effects to be counted. That and the fact there was only a single subject is damning for the experimental quality of the paper. – matt_black Oct 6 '13 at 13:39
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    I forgot to mention: I raised this over at Stats.SE and they seemed to agree the results are very weak. – Oddthinking May 2 '14 at 6:52

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